Dr. Layne Norton
Appearances
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
We are going to make sure that these studies equated calories for the reasons we talk about. You got to compare apples to apples. Right. So a lot of studies will come out saying fasting produce more fat loss. Low carb, but then they didn't control calories and it's very likely these people just ate less.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
The only difference they saw was that LDL cholesterol improved a little bit better in the low sugar group. And that is probably a function of the fact that the low sugar group had more fiber. We know fiber can bind to cholesterol and lower LDL cholesterol in the blood. So when I saw that, I was like, oh, man.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And then when I look through all these other studies with similar kind of controls, they pretty much show the same thing across the board on metabolic health, on inflammation. Like inflammation really isn't different if calories are controlled with high sugar versus low sugar as long as you're getting enough fiber. What about feelings of satiety? Well, that is the real downside.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If you're eating a 1,200-calorie diet and 400 calories are coming from pure sugar, I mean, you're probably going to be kind of hungry, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
What I tell people is I would focus less on like sugar intake. I mean, if you want to focus on added sugars, that's fine. focus on calories, protein, and your fiber content, right? Because if you're getting enough fiber, it's going to be hard to eat a lot of junk doing that, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
When we look at the sugar intake and calorie levels, all that kind of stuff, actually a great example would be the case of Dr. Mark Haub. Are you familiar with him? He's at Kansas State. He's a nutrition professor. In 2011, he got the name the Twinkie Diet Professor. I'm not sure if you saw this.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So they controlled calories and they controlled protein, which is also important because protein changes the composition of weight loss. Protein has a thermic effect. Protein increases lean mass retention. So that can change how much fat you lose. And I think they also had a requirement of like a minimum of four weeks, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Right. So he he he asked his students what they thought mattered more for for fat loss, the calories you eat or the food choices you make. And they said most of them said food choices. And he said, OK, let's do an experiment. Do you think if I do an 1800 calorie diet from ultra processed foods exclusively. then I will lose weight and get healthier. And most of the students said no.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so for 12 weeks, he ate 1,800 calories. He called it originally the 7-Eleven diet. He basically was like, if I couldn't get to the 7-Eleven, I didn't eat it. Now the caveat is he had a multivitamin and he had some whey protein so that he was getting enough protein because it's hard to get protein from some of those ultra-processed foods.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But 1,800 calories and he lost 27 pounds and all of his blood markers improved and his insulin sensitivity improved. Now, that seems crazy to a lot of people, but for those people who have worked and looked at blood work with weight loss and whatnot, I mean, it's not that surprising. That is one of the biggest levers for metabolic health. And so when they asked him afterwards, what a great diet.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You could eat all this junk food. And he goes, well, not really. It's 1,800 calories of junk food. It goes really fast. I was pretty hungry and honestly, like at first week it was like, oh, this is kind of nice. And then after that, I was like, you know, I'd really like just a really big salad, you know, just something satiating. So again, no solutions, only trade-offs.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
There is a benefit to being able to go, well, I can, if I can fit into my calories, it's okay. As long as I get enough fiber and protein. Yeah. The trade-off is, It's a high budget cost, right? Same thing with people's – the data on like moderate alcohol consumption shows that it doesn't impede fat loss. It doesn't if you account for the calories in it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But I'll tell people like, hey, do you really like – if you have like two craft beers, do you really want to spend 400 or 500 calories on like 24 ounces of fluid that's not going to impact your satiety at all? And so I think a lot of people view this from a very black and white lens, right, where it's like, oh.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Lane says or this person says, I can eat sugar and lose fat so I can eat as much sugar as I want. No, no, no, no, no. Because there are practical limits to this. Right. But take somebody like me. Right. If my calorie intake is my budget, I train two, three hours a day.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
My maintenance calories are anywhere from thirty three to thirty four hundred calories a day, which is a not crazy amount, but a healthy amount for somebody of my size. I have a decent-sized budget, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If I can still get my protein in, get my fiber, hit my micronutrient targets, and I have calories left over for energy filler, sure, just like if somebody makes a million dollars a year and they want to go buy a sports car, it's not a great investment. It's not a good investment at all. Why wouldn't they just bank every single cent they make?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Well, because maybe for them, having that little reward motivates them to keep doing what they're doing and making that level of money, right? But if you're making, let's take loans out of it, right? If you're making $100,000 a year, does it make sense to spend $90,000 on a sports car if it means you can't pay your mortgage anymore? And you can't save money for retirement.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And the outcome was looking at changes in fat mass, not fat oxidation, not energy expenditure. It actually looked at the outcome that they cared about. And they They showed no difference, right? So I thought, well, that's a very well done meta-analysis because the inclusion criteria make a lot of sense for the question that they want to answer, which is not, is one diet easier to stick to?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You can't meet your obligations. No, it doesn't make sense, right? And so if you're a small woman, small lean mass wise, who is trying to lose some weight, does it make sense if you're eating 1,200 calories a day to lose weight to spend 300 calories of that on some ultra processed junk food? I don't think it does. But if you're...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
an Olympic athlete who's burning four or five thousand calories a day. Good luck eating that level of calories from good, minimally processed foods. You're going to feel full all the time.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But I think that that's what you're saying right there is that's where the individualization comes in, right? Like it's contextually dependent and it's dependent on the individual and what makes sense for them. And I think we, as people, if we find something that works for us, we're a little bit too quick to want to evangelize everyone else around us. Because we do want to help.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
We do have good intentions for the most part. And we overgeneralize. And I've – for me, again, like counting macros, flexible dieting, when I – I dealt with a little bit of binge eating when I was young when I first got into bodybuilding because I was trying to eat clean. And I would – I was in college.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So my buddies would order pizza or whatever and I ended up eating like an entire pizza by myself, right? Yeah. And so once I allowed myself to just have that – the foods I wanted in moderation, I just got brutally consistent, right? So that for me, that was the switch that flipped. But other people – That may not be the right solution.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I think we make a bunch of, well, that diet worked for me. We assume physiology when actually I think it's much more psychology and just trips that compliance algorithm in somebody's head and it makes sense. And if we could just be willing to say more often, hey, this is what I do, but I like this and you don't have to do it. Maybe try it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Not, is it more practical? The question was mechanically important. do these diets produce differences when we're comparing apples to apples in actual fat loss? And the answer was no, right? And then when you look at the other meta-analyses that have been done, they tend to kind of support that, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I think it's all about making the appropriate apples to apples comparison, right? Because if we're looking at addition studies of, you know, adding something to a diet, adding omega-6s, linoleic acid, linoleic acid, whatever, Well, if you're adding those, you're adding calories, which is a confounding variable, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So ideally what the real question is, because the debate tends to be the people who are anti-seed oil tend to be very pro-saturated fat. And so the question really is, okay, if we swap out these things in a one-to-one ratio, what is the outcome, right? So not like when outcome, I mean metabolic health, inflammation, those sorts of things.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So in the studies, I have yet to find a good human randomized control trial where they give polyunsaturated fat in place of saturated fat, exchanged at a one-to-one ratio, and see negative actual outcomes.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, I've looked less at that just because people ask that question yet less. But it seems like both PUFAs and MUFAs are better than saturated fat in terms of metabolic health and risk of chronic vascular disease, those sorts of things. Does anyone have a problem with olive oil? I'm sure you could find somebody with a problem. There are people with problems with water now.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So the first thing I'm going to look at is, all right, these meta-analyses tend to be looked at as kind of the highest form of evidence, right? Because you're compiling a bunch of different studies, which, listen, we know there are bad studies that get done. I think the amount of studies that get like just straight up faked is probably much lower than people think. One hopes.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I'm not aware of anything, but I will say like if you extend the logic of the seed oils crowd or anti-seed oils crowd, which actually I'm going to make a new logical fallacy, which is just appeal to seed oils. Because so many times when I've laid out this data, I have people go – basically like have a freak out and go, but seed oils, how dare you defend seed oils?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I'm like, I'm not defending them. I'm just talking about data.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I find this actually very funny as somebody whose research was funded by the National Dairy Council, the Egg Nutrition Center, and the National Cattlemen's Beef Association that – Somehow, I would be the person who would be – and all these things act in opposition too. It's like, well, you think I'm pro-seed oil, but then over here I've been defending meat with this thing, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And then over here I've been defending – sorry, defending is the wrong word. Discussing the data on sugar, which by the way, those would be in opposition to each other because you're – And you're very pro-fiber. Right, right. So, yeah. Yeah.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So – and even when I talk about saturated fat, I don't like say it's toxic and it's going to – I say, hey, it raises LDL cholesterol, which is an independent risk factor for heart disease. I'm just discussing it, right? So I'll say what I said online, which is I don't defend nutrients. They don't need defending. There's not ethical considerations here.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If you want to eat them, I don't think you're less of a person. I find it curious that some people get so – emotionally and just like ethically entrenched around certain nutrients. So the logic goes something like, well, you have these multiple double bonds and so they can be oxidized.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so that oxidation is going to cause an increase in inflammation, which is going to cause heart disease and cancer. Okay. Well, olive oil is a monounsaturated fat. It still has a double bond. So by that logic, it would still be worse than saturated fat. So when we look at trading out – and MUFAs would fall in this too, I believe.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If you look at the cohort data, polyunsaturated fats substituted for saturated fats have a stronger effect on reducing heart disease than monounsaturated fats. But monounsaturated fats do still tend to have – an effect of reducing the risk of heart disease compared to saturated fat.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Right. And just to add some nuance to it, not all saturated fat is created equal. There are like stearic acid, I believe, doesn't raise LDL cholesterol. But in general, saturated fat is going to be something that raises cholesterol more. It also...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Again, I'm thinking of several randomized control trials where they feed the same calories, they feed the same amount of fat, and they just have people either eat saturated fat or polyunsaturated fats. You see either neutral or positive effects on inflammation. You see neutral positive effects on liver fat.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You see neutral positive effects on basically overall metabolic health and insulin sensitivity. So again, and Paul actually counted this one time and he cited a study looking at, I think it was, I don't want to say it wrong, but it was like giving omega-6s and they saw an increase in lipid peroxidation. I don't think they were comparing it to saturated fat. I could be wrong.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But again, this is an example of a mechanism, right? So lipid peroxidation mechanism. We can try to project what that might mean down the road. But when we look at actual levels of inflammation, actual risk for cardiovascular disease, actual insulin sensitivity, actual levels of liver fat, these are outcomes. We can actually, if we're worried about those, we can actually measure them.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And again, some studies show no difference. Some studies, some of the studies I've seen on like inflammation between polyunsaturated fats and saturated fats don't really show a difference in inflammation. But I'm not aware of any that show it going in the opposite direction, where substituting in polyunsaturated fats actually raises inflammatory markers like CRP and IL-6, those sorts of things.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Um, and actually one of the things I tell people when they're worried about, you know, fructose activates the novel lipogenesis in the liver. And I'm like, well, here's this study where they overfed fructose and saturated fat by the same amount and saturated fat increased liver fat by 70% more than fructose. So if you're worried about fructose, you better really be worried about saturated fat.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Um, so that's kind of where I land on it. I just, you know, maybe I'm missing some data, but when you're, when you're looking at these studies, again, I'm looking at not one study, not two studies. I'm looking at 50 studies or however many studies there is on the topic. And I go on this forest plot, where do they land? Um,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And when they're almost all on one side or neutral, I feel pretty confident that that's something not to worry about, right? So let's take another discussion to tie this in. I think this will help people understand how I come to a conclusion about this sort of stuff. So I do not necessarily think red meat is carcinogenic, even though the IARC has classified it as probably carcinogenic, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because when you look at the studies, you can find studies that associate red meat with cancer, and you can find studies that show no association of red meat with cancer. And so it's kind of all over the place. Now, there's probably more that show the association than don't.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But when you look at studies where they control for overall diet quality, so I'm thinking of a study out of Canada back in 2020. I think the author was Maximova, I want to say. They looked at different levels of red meat intake and incidence of cancer, but also with different levels of fruit and vegetable intake.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so what they found was at low levels of fruit and vegetable intake, lower red meat consumption reduced the risk of cancer relative to higher red meat consumption. But at high levels of fruits and vegetable consumption, I don't think there was a significant difference, but actually the high level of red meat consumption was lower risk than low red meat, high fruit and vegetables.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I believe I have that correct in terms of the absolute risk. And I don't know if it was statistically significant, but what that says to me is red meat is more of a proxy of poor overall diet quality.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And if you control for that with some diet proxy of fruit and vegetable intake, you know, if you're eating a lot of red meat and a lot of fruit and vegetables, there's not really a whole lot of room in your diet for a bunch of crap.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Well, it's simple. You could probably still do it in a restaurant, right? Because you just ask for meat and vegetables, right? It's socially compatible. So there is some beauty in simplicity. There's beauty in what I do, which is I track everything and I can have whatever I want. You're going to have to have some form of restriction to lose weight.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You pick the kind of restriction that you can stick to, right? So... Bringing that all back. So you have this data that's all scattered on meat, right? And then let's look at something like dietary fiber, okay? Because people say, well, you can't establish causation. Some people might say, well, the carnivores might say, well, it's all healthy user bias.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If it was healthy user bias, there'd be some disagreement in the data. And there's no disagreement in the data. I am not aware of any study. looking at dietary fiber intake or fruit and vegetable intake that doesn't show reduced risk of cancer, reduced risk of cardiovascular disease, reduced risk of mortality, usually in a dose response, and it is very consistent.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Now, some studies might show more of a risk reduction versus other studies, but if we're doing a line of a forest plot and this is risk reduction, this is increased risk, everything's on this side, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Right. So and there's like kind of a dose response. So that's when I become even without randomized control trials necessarily. That's when I get pretty confident. OK, this is a very consistent effect. And there's a dose response. And we're seeing a bunch of different populations across a bunch of different countries in a bunch of different labs. OK, I feel confident.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so for somebody to make the claim that seed oils are toxic or that they're bad for you independent of the calories, I mean you're basically relegated to using animal studies, in vitro mechanisms, and then epidemiology, which trying to like tie those all together – I mean, that's not really high-quality evidence. Really high-quality evidence is that you have the mechanisms, okay?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
There's a mechanism, right? Because if there's an outcome, there's a mechanism. The animal data agrees with it. There's a dose response. The human randomized controls trial supported, and then the epidemiology supports it. Like in order for something to really truly be strong evidence, we need that. Now let's take our example of fiber again, right? Epidemiology supports it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
We have mechanisms in terms of short chain fatty acid production, in terms of like insoluble fiber, moving, like getting food through the gut faster might be actually better because there's some, some, I don't want to use this word lightly, but like
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Some semi-toxic end products of like metabolism in the gut that if they stay around too long, it might have negative interactions with some of the colorectal cells. And that may be one of the reasons that insoluble fiber helps decrease the risk of colorectal cancer. So we have the mechanisms. The animal studies show it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
When we do the human randomized control trials looking at shorter term surrogate markers, they show it move in the right direction and the epidemiology is in the right direction. That's when I become very confident about something. So I'm not ready to say like, hey, seed oils are really, really good for you and you should have a bunch of them. I'm not saying that.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Obviously, they're calorically dense, right? People add oil to stuff and it adds calories, right? But anybody trying to claim that there's strong evidence that they're bad for you, we have very different definitions of what strong evidence is. And you have to apply your logic symmetrically.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If you were going to use a certain level of logic for one thing, you have to apply it to another thing, right? And I'll give you an example of this. Like when we were talking about the cruciferous vegetables and isocyanthanates and it reduces iodine, I said – Well, this person was advocating for a meat-based diet.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I'm like, okay, well, there's NUE5GC in meat, which by the way, they found antibodies for that in human thyroid. Now, I'm not saying that meat's going to mess up your thyroid, but if you're worried about this stuff in cruciferous vegetables, don't you have to worry about it in meat too?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I think that's probably pretty small. My experience is the same as you. I didn't see much of that or I never saw it observed.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because if you're applying that logic symmetrically, I would actually argue that there's stronger evidence that you're worried about the NUE5GC in meat since you actually see those antibodies show up. So with the seed oil stuff, I'm like, okay, let's apply this logic to saturated fat for a moment. All right. So do we have a mechanism? We do. Saturated fat raises LDL cholesterol.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Well, LDL cholesterol can penetrate the endothelium. We know this. So there gets to be this debate about small oxidized versus large fluffy. Both can penetrate the endothelium. Even large LDL can penetrate the endothelium. Now, small oxidized penetrates more easily, but it carries less total cholesterol and deposits less cholesterol in the endothelium. Large
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
doesn't penetrate as easily, but per unit of LDL cholesterol, it's depositing more cholesterol because it's bigger. The net effect is both are equally atherogenic in the end. So we have the mechanism, right? Now let's look at the epidemiology. Well, the epidemiology tends to support it as well. And then if we look at the
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Really what, for me, changed my mind, because I used to be somebody who was on the side of, LDL doesn't really matter, it's HDL to LDL ratio, was when I saw the Mendelian randomization studies, which for those who aren't familiar, you're basically looking at natural polymorphisms on genes that cause differences in secretion of LDL, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And since LDL is a lifetime exposure risk, meaning if you're doing a two-year randomized control trial looking at LDL levels, it says nothing about what they ate before. And, you know, in that timeframe, what's the likelihood people are going to have heart attacks or some sort of myocardial infarction? It's pretty low.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
now that we have all these like data banks of, you know, blood samples and whatnot from people from all these old studies, they go back and do these analyses. And when they look at LDL cholesterol and plot it, so lifetime exposure to LDL cholesterol and plot it against the risk of heart disease, I mean, you can pretty much draw a straight line through it. And so to me,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
That's pretty strong evidence. If you're if you want to apply the same logic of what we have this, you know, and LDL, by the way, can cause inflammation in the endothelium. So you have that damage to it because the apolipoprotein that attracts inflammatory markers. So. People are getting some of this cart before the horse. And then the other thing that sealed it for me was, again, like HDL.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, I think, you know, usually if I see a paper and the conclusion, like, just straight up, I go, oh, I don't know about that. When I go in and I read the methods and I read how they analyzed it and I read how they measured things, 99% of the time I walk away and go, okay, I'm not surprised they found what they found, right? Because, again...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
They looked at the same thing at HDL. Turns out HDL is just kind of a marker of metabolic health. It's good to have high HDL, but HDL itself doesn't appear to be protective because if they raise it with drugs or look at people who secrete more or less, it doesn't seem to independently modulate risk of cardiovascular disease. So all that to say, saturated fat is really –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Only an issue I would say for the LDL, the fact that it can raise LDL and there is some evidence it's not necessarily good for the gut microbiome because the bile salt in products from emulsifying saturated fat, cause it requires more bile that those might be toxic to some beneficial species of bacteria. But here's what I'm not saying. I'm not saying don't eat any saturated fat.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
What I'm saying is again, your overall diet quality is what matters. I think it's fine to have some saturated fat. I think probably try to keep below seven to 10% of your daily calorie intake. What also matters is there's no solutions, only trade-offs.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so if somebody says to me, you know, I was able to lose 50 pounds on low carb and everything got better, but my LDL went up a little bit and they felt like that was the only thing they were able to be consistent with. I'd say on balance, they're probably better off with that slightly elevated LDL than than they would be if they'd kept the 50 pounds on.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Now, I would argue if they had lost the 50 pounds and lowered their LDL, their overall risk would be lower than it is now. But again, we have to look at what can somebody consistently execute. So all that to say, I'm not saying you should consume seed oils. I'm not saying that there's no negative downsides.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But if we look at comparing it to a comparable molecule of saturated fat, there's a much more compelling argument that saturated fat is bad for you versus seed oils.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I ate a steak right in front of a vegan.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I was originally going to order fish and they said, it's okay if you want to get a steak. And I said, okay, if you say so. Now they did make a couple of comments in jest during the meal.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
A lot of, and this does happen and it shouldn't, but a lot of studies are set up to kind of find what people want to find. You can bias things in a certain way.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And that's a great way to couch that of, I don't have data for this. Personally, I don't do it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, you'd prefer to have a steak as opposed to having the cola. Right.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So let's take the insulin thing first. So an interesting mechanism that they're showing there is What I would say is there's been a couple of meta-analyses now looking at different non-nutritive sweeteners and their effects on insulin, and they don't show an effect. So there's no real effect. And let's just kind of play it out logically a little bit.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If there was a significant effect on insulin, one of two things is going to happen. You're going to see a drop in blood sugar because you're not eating anything. Right. So most of us, if we eat, if we drink a diet soda, we don't then go hypoglycemic. Right. Or if there is an increase in insulin, if blood glucose isn't dropping.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
then there must be a corresponding increase in glucagon, which is basically offsetting all of insulin's issues. I don't think either of those things happen. I think it's inert and that the research, the meta-analyses tend to show this. There was a – I'm thinking of two meta-analyses where they looked at these. They looked at glycemia.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
They looked at insulin sensitivity and they looked at insulin release and they just didn't see any effect. Now, when it comes to, what was the second point?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
OK, when we talk about studies, we're always talking about means and averages, right? I leave open the idea that there could be subsets of populations, that there could be individual responses. I leave all that open. So on average, if that's true. And there is a conditioned response. We're worried about, well, one, is there an effect on appetite where people are going to eat more?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Even if those things don't have calories, they're not going to make you fat. There's no insulin release. Okay, they're stimulating you to eat more. Well, if we look at the randomized control trials where they tell people, hey, instead of regular cola, drink diet cola.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If that was true, an actual outcome, we would see people on diet soda either not lose weight or gain weight, definitely compared to water. And probably similar compared to a regular cola, maybe a little bit less, but we would expect to see weight gain. We actually see the exact opposite thing. So we have several randomized control trials now where people like comparing not just diet soda.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I don't want to say diet soda. A lot of them are low, no calorie beverages is kind of the what they talk about because not everything's technically diet soda. But I think people know diet drinks in particular. Where they're comparing them, they tell people either switch out – either have cola, either have diet soda or – sorry, diet drink or just use water.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Now, they absolutely – every single one of these trials, they lose weight going to diet drinks, usually a pretty significant amount of weight.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And you have to say what you're going to measure.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So then what's really interesting is they've done direct comparisons to water. And some studies don't really show a difference, but several studies and several meta-analyses now have shown that when people –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
if they have either them use water in place of regular soda or diet drinks in place of regular soda, the people actually lose a little bit more weight and it's statistically significant with the diet drinks. Now I don't think diet drinks are fat burners. Okay. They're not causing you to have increased energy expenditure, but if you are somebody who is used to a sweet taste and
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If you switch to water, perhaps you're seeking out that sweetness elsewhere. And so maybe those people are consuming a little bit more sweet food or whatnot. Whereas in the diet drink group, maybe that's filled that sweet taste for them. So... I don't get into the – again, this gets – like people get very like ethically charged about this. What's wrong with drinking water?
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Dr. Layne Norton: Tools for Nutrition & Fitness
There's nothing wrong with drinking water. If you can drink water, you feel satiated and you maintain your – I'm just chuckling because if drinking water becomes an issue online, then I might quit. No, it already has. All right.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah. Well, so again, perhaps that mechanism exists, but at least on average, it's obviously washed out by the fact that – For whatever reason, for most people who do this, they get a little bit more satiety out of consuming a diet beverage as opposed to substituting water for a beverage.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Now, again, if you're somebody who you can drink water and you don't have an inclination for diet drinks, then don't do it. You don't need it. But again, I look at it as we need to lower the barriers for people to start getting healthy.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And unfortunately, a lot of people with the message of just drink water and they'll say, well, diet soda is just bad for you as regular soda or it's worse for you than regular soda. Their intention might be I just want people to drink water. But the outcome is people go, well, I can't imagine getting my soda, so I'm just going to drink regular soda then, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so while your intention was positive, the outcome is actually kind of disastrous, right? And so we have to disconnect what the intentions of the message are from what it actually produces. And so that's why I say, hey, if we're moving levers, if somebody is obese and they came to me and they're like, well, you know, I drink five colas a day, I'm like, fantastic, because I'm thinking –
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Dr. Layne Norton: Tools for Nutrition & Fitness
Five diet sodas instead. And now we have just saved 750 calories and you're going to start losing weight just by doing that. Right. Which, again, people say, well, what about 100 years down the road or whatever? I'm like, well, most of these sweeteners have been around for decades now. We do have quite a bit of data on them. But let's say that there is something we don't want.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Again, I'm shooting the alligator closest to the boat, right? Like, we know what obesity does. So, and people who do these diet drinks, lose weight, they get more metabolically healthy. So, again, if it comes down to soda or diet soda... by all means, let's do the diet soda. And if there's some small nugget of effects to it, we'll deal with them. So that brings me to the gut microbiome.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Most of the research studies in humans where they use reasonable doses don't really show much effect on the gut microbiome. However, there are a few with particular sweeteners like sucralose that That do show an effect. Now, there was one that got a lot of play and you and I actually talked about this. I think we actually talked on the phone about this. And it was an interesting study.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I thought it was well done. But I want to be careful about how overgeneralized it was. So the first part is in this study, they selected for people who basically they did a very, very like intense selection process where.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I think there was over 1500 people who were like originally included in the study and they whittled them down to like a hundred something because they wanted people who had really hardly ever used artificial sweeteners in their life. And that's a pretty small percentage of the population. What they found was a lot of people submitted saying, I don't use them. I've never used them.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And they found that when they gave them sucralose, that the composition of their microbiome changed and they called it dysbiosis. And I'll come back to that because that's a scary sounding word. First off, what's interesting is if you're somebody, that population that they're selecting, those are probably people who have been specifically trying to avoid them.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because if you're not, even if you don't try to consume them, They're everywhere. So if you haven't been consuming them, it's likely that you're specifically trying to avoid them, which probably means that you have negative thoughts and beliefs around artificial sweeteners. And again, we've discussed the power of belief before. I'm not saying it was a bad study because of that.
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Dr. Layne Norton: Tools for Nutrition & Fitness
But I will say like there's very rarely do I say this was a bad study. Often what I'll say is, you know, I don't agree with their conclusion based on their data and their design, but the data is the data, you know. I was just very fortunate, again, to my PhD advisor. I have so much gratitude because he just right away was like, hey, if we're wrong about something, that's fine, you know.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I'm just saying we have to be careful about how much we over-interpret this research data.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Maybe. I mean, again, we've talked about the power of belief is very powerful. I have no way to Support that, right? I'm just saying be careful before you overgeneralize. Plus, it was a two-week study. Just two weeks? Yes, it was two weeks. Now, again, two weeks is enough time to show differences in the gut microbiome. Actually, a few days is typically enough time.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
There was another sweetener that I think had a change. It might have been saccharin.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Sucralose is pretty ubiquitous in a lot of diet products and whatnot. But like, being frank, my whey protein powder with outward nutrition is sweetened with sucralose. I mean, it's a great sweetener. And so some people will take that as, well, of course, he's going to defend sucralose because it's in his protein. But if I thought it was really bad, I would just use a different sweetener. So...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
What I will say as well is gut dysbiosis sounds bad, but it simply means that the gut microbiome changed. And I have several friends who are gut microbiome experts. And they'll, when we sit down and talk about this stuff, they're like, I mean, their takeaway is, yeah, like 50 years, we'll probably have a really good idea of this stuff.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But right now we like, we just know that certain things change it. We don't really know, like if it's a good change, bad change. So I'll give an example. There was another study that did show a gut microbiome shift with sucralose, and they showed some of the species of bacteria that were increased or decreased.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And one of the species that was increased, I believe, I'm going to butcher this so badly, I think it was Blaudia coccitis was the name of it, or at least how I tried to read it, right? Because these are very, like, strange Latin words.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Now, what's interesting is this species of bacteria was associated with better metabolic health, lower risk of obesity, better insulin sensitivity. And so I kind of walked away saying, well, couldn't you make the argument that sucralose actually changed the gut microbiome for the better based on some of this data? And so I'm not saying that. What I'm saying is the following.
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Dr. Layne Norton: Tools for Nutrition & Fitness
We don't really know if that change to the gut microbiome is a good change, bad change, or neutral. We just know that it changes. So if you want to avoid, fine. But if you're somebody who really struggles with moderating your intake and a sucralose or an aspartame or whatever have you helps you moderate that intake, then again, you're shooting the alligator closest to the boat.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Let's focus on the big stuff, right? Mm-hmm. And that's kind of where I land. And again, I hold open that perhaps my mind will change and adjust. But sucralose has been around a long time. The other thing people bring up is cancer. They'll bring up cancer with artificial sweeteners. And I'll give you an example why I'm not worried about this.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And I'll give you an example of how results can seem to conflict, but, you know, how things are designed. We actually wanted to test, does protein quality make a difference? And we wanted to look at it at like, not low, but like just kind of like RDA levels of protein. And we saw that protein quality did make a difference at those levels of protein.
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Dr. Layne Norton: Tools for Nutrition & Fitness
First off, you have to keep in mind the negativity bias in the news. All right. Things that are negative are much more likely to get play than things that are positive. OK, think about how much you hear about this causes cancer. This causes heart diseases versus this protects against this. This protects against this.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Right. So you hear a lot – people are like, oh, man, all these studies say that these cause cancer.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So again, I'm going to give a shout-out to ConsenSys because it's a great AI tool that basically will give you – like if you ask it a question and there are some filters that help with that, it will give you kind of like this percentage of studies say yes, this percentage say possibly, and this percentage say no.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And if you type in, does aspartame cause cancer, for example – 80% say no. And then like I think the split is like 13% say possibly and 7% say yes, right? But you would never know that from like listening to social media, watching the news. But I want to point out one study in particular that did show an association of aspartame intake with cancer. And it was from the NutriSanti cohort.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I think that was out of France, like 100,000 people. And they looked at – like people who didn't use it versus people who were like low moderate users and then people who were like high users. They categorized them to tertiles. And between the non-users and the low moderate users, there was like a, I believe it was like a 15-ish percent relative risk increase in cancer incidents.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And that's what got reported in the news. And then that dropped to like a 6% increased risk in the high group. So it did this, which I'm not aware of any carcinogens that they actually decrease in terms of the risks, like carcinogenesis as they go up in like the concentration.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And so to me, you know, one of the things you've got to realize, my PhD advisor used to say, if you torture the data enough, it will confess what you want it to say. And so if you go through a large group of people, and you start trying to associate things with other things, you'll find things, but you gotta be very careful with how strongly you interpret it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so for me, again, if I'm, if I'm feeling strongly about for me to feel strongly about something, there has to be some kind of dose response, or at least like if there's a bell curve, sometimes you see that, but you know, very rarely, especially with, with cancer stuff, usually this is kind of a linear effect. And so again, That's where I land right now on artificial sweeteners.
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Dr. Layne Norton: Tools for Nutrition & Fitness
But if you look at experiments where people are feeding like high levels of protein, like 1.6 to 2 grams per kilogram of body weight, you don't really see much difference in lean mass or protein synthesis with looking at different protein sources. Well, that's because it's much more regulatory on a low end because you're closer to those thresholds that trigger that signaling.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I land on them as a useful tool for a lot of people. I don't think they're magic. I think they occupy that sweet taste for a lot of people. And if you can completely avoid them and abstain from them and you're perfectly happy, then by all means do that. But if they help you maintain a healthy body weight, then by all means do that.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So I think it's not so time dependent. And like I said, it's more about what you do over the course of 24 hours and, you know, in your day to day lifestyle. But sleep, as you said, also your nutrition.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So being consistent with your nutrition and you don't have to get in, you know, ultra fast digesting carbohydrate and, you know, 50 grams of whey isolate right after, you know, but it's probably a good idea within a couple hours of finishing your workout that you have, you know, a meal with high quality protein and,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And that you're just eating an overall healthy diet throughout the course of a day. And we've kind of discussed that at length.
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Dr. Layne Norton: Tools for Nutrition & Fitness
This is going to circle back to our mechanism versus outcome. And this is one where I changed my mind because of seeing outcomes. So the reason this comes up is fructose, your muscles and other tissues lack the enzyme to turn fructose into muscle glycogen. Your liver has that enzyme. So your liver can take fructose and turn it into liver glycogen.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So that has led some people in sports science or research to say, well, don't have fructose after a workout. Actually, fructose is kind of a dead carbohydrate, right, because it's not going to replenish muscle glycogen.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And then I was reading a study from Tracy and Josh Anthony, which were, they came out of Lehman's lab and they actually are responsible for really fleshing out a lot of the mTOR pathway, a lot of that translation initiation pathway. Very, very brilliant people. And I was glad I got to see them a few weeks ago when my advisor got his award. Tracy personally taught me how to Western blot.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so we wanted to show at that level That it made a difference. But then we also acknowledge, okay, at this level, it probably doesn't make as much of a difference. But people can read those things and say, well, I don't believe studies because they're conflicting.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So thank you, Tracy. They did a study where they looked at glycogen replenishment after exercise, giving either sucrose, which is 50% glucose, 50% fructose, or pure glucose. And actually, if I recall correctly, they actually got a little bit better muscle glycogen replenishment with sucrose. Now this, how do you explain it? That seems completely counterintuitive. And there, I believe...
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Dr. Layne Norton: Tools for Nutrition & Fitness
Again, it's been some time since I read this paper, but I believe the explanation was by providing some fructose, what you're doing is you're kind of satiating the liver's need for glucose. And so that glucose that does come in from sucrose can then kind of just bypass the liver and be available for muscle. Whereas if you're getting pure glucose, the liver is going to start picking things off.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Now, if I recall correctly, it wasn't a big difference in the rate of glycogen replenishment, but – The other thing is people don't realize, well, even though fructose can't be used to replenish muscle glycogen directly, you forget about how the body operates in terms of whole body metabolism. And you can store fructose as glucose, glycogen, in the liver.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And then the liver can release that glycogen at some point into the bloodstream. And then that can be taken up by the muscle and turned into muscle glycogen. So again, what it really boils down to is what are you doing on a 24-hour basis? And what I will say too is the rate of glycogen replenishment gets really tossed around a lot as something really important.
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Dr. Layne Norton: Tools for Nutrition & Fitness
For the most part, the rate isn't so important. If you're eating enough total carbohydrate on a total daily basis and enough calories, you'll replenish your muscle glycogen. And most people always say, dude, you're weight training for an hour. You're going to do it again in 23 hours. You got plenty of time to replenish that glycogen. You don't need cyclic dextrin or dextrose or whatever.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so I'm not really worried about that. I think where the rate of glycogen replenishment really matters is when you're dealing with athletes who have multiple events in a day, right, where it is they're going to perform and then they need to replenish quickly before they go to the next event.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But no, when you read how it was designed, I can easily say, like, I remember there was a, somebody sent me a study and said, well, how does this fit with your data, which... They were comparing rice versus whey protein and found that both stimulated protein synthesis to the same degree. And I said, well, they used 40 grams of protein.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Or, you know, people obviously doing like endurance exercise where like Ironmans, triathlons and that sort of thing where, you know, getting in that replenishment and keeping it going is very important. But I think for the average person who's just exercising once a day, not really a big deal. Just make sure you're eating enough total carbohydrates.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So for you, the berries and the fruits and the whey protein afterwards, excellent.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So stress management, like you said. So I am blessed enough that I currently live and home on Tampa Bay and I get to watch the sunset over the water every night. And that might seem like a weird thing, but I really feel like that has helped with my stress level.
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Dr. Layne Norton: Tools for Nutrition & Fitness
This is right in your wheelhouse right here.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I was talking to a friend of mine. We were sitting out. I said, well, Andrew would approve of the sunset viewing. He might not approve of the bourbon I'm having with it, but –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah. So whatever, cause you just slow down a little bit, you know, and just decompress and feel better. And so, I mean, another thing I'll do is I'll, you know, once the, if I had the kids, once I go to bed, I'll go downstairs and I'll lay on the couch with my cat and I'll play a video game. Nice. You know, just relax, decompress, decompress, you know, things you enjoy.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I think things you enjoy, like obviously like you can't drink a 12 pack of beer and have that be conducive to, to, to that sort of thing. But the other thing I will say is I think a lot of people focus too, Too much, especially with resistance training. There's some evidence that being just overall active lifestyle, like going out.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I remember when I was first getting into lifting, like back in the early 2000s, the guys like I go in and I lift and I lay down the rest of the day. Right. Because I got I got I got to recover. Right. I think the research actually suggests that you're better off having kind of an overall active lifestyle.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, it's important to rest and recover, but it's probably important to move your body throughout the day. Active recovery does have some good data on it.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Like if you get protein high enough, you can max out protein synthesis regardless of the form of protein you're using. And so that's just like one of those examples, right? So when I'm looking through this stuff, I'm looking at, OK, does there seem to be a consensus in the data? And then is it like in these meta-analyses, does the inclusion criteria make sense?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And then if there's no real agreement amongst the meta-analyses, then I'm looking at, OK, what do the most tightly controlled studies show, like in the randomized control trials? And then I'm kind of like basing opinion off that. But, you know, the hierarchy of evidence, the pyramid, you got meta-analysis, systematic reviews, randomized control trials.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Well, first off, I will never make somebody apologize for giving a long-winded preamble, right? Because you know how long I'm about to go.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So- I will tell you, I actually, like after I commented on that post, I went and looked up some more research and I've actually changed my mind a little bit. Okay. Which, which probably wouldn't surprise you. I haven't completely changed my mind, but I've shifted a little bit. So first off, my first thought was exactly what your thought was.
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Dr. Layne Norton: Tools for Nutrition & Fitness
This is all getting broken down to constituent amino acids. It's not like you're taking collagen and just like putting it in the place you want it. Like just, you know, like that sort of thing. So, And my skepticism was also because one of the highest quality protein metabolism labs out there where Jordan Tromelin is, is Luke Van Loon.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Luke Van Loon's lab is one of the best protein metabolism labs in the world. And they were publishing research back when I was in graduate school. In fact, I think Jordan and I were actually in graduate school at the same time. So they did a study where they looked at – after exercise –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
giving either whey protein or collagen protein, and they looked at skeletal muscle protein synthesis, and they looked at connective tissue protein synthesis, right? And they saw no difference between whey protein and collagen protein in connective tissue synthesis after exercise.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so, by the way, collagen did not stimulate muscle protein synthesis, even at like 25 grams, I think it was, which most protein sources, even like plant protein sources, will stimulate muscle protein synthesis at like 25 grams.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So it's low quality in terms of skeletal muscle. Anybody who's telling you like collagen is good for building muscle, I mean, it's better than no amino acids, but it's one of the worst you can get in terms of all protein sources. So that study, again, since I know this lab, I have a lot of trust of the data that comes out of there, right?
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Dr. Layne Norton: Tools for Nutrition & Fitness
And it was a well-designed study, it was a well-executed study. But then there's these meta-analysis out there, looking at skin, looking at, you know, even like some were trying to make associations with connective tissue injuries and whatnot. And again, I'm always... a little bit have the heebie-jeebies when we jump straight to, we have an outcome, but we don't know what the mechanism is, right?
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Dr. Layne Norton: Tools for Nutrition & Fitness
And then I started reading a review by Luke Van Loon, actually, and was talking about like the, so the collagen, is three alpha helixes. So if you think about DNA, right, it's a double helix, right? So think about three helixes. And an alpha helix just refers to the way a protein is shaped. And They have a very large amount of glycine. So glycine is a non-essential amino acid.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And every third residue in collagen in the three alpha helixes, every third residue is a glycine molecule. So 33% of collagen is glycine. And then I want to say 10% is proline, and then another like 10%-ish is hydroxyproline. So proline that's had a hydroxyl molecule added to it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And that's done – apparently the – nobody needs to know this, but just for fun stuff, the hydroxyproline helps stabilize the structure because of the hydrogen bonding with the hydroxyl molecules, which I found interesting. So you have these three amino acids and amino acid derivatives that make up over half the amino acids in the collagen protein.
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Dr. Layne Norton: Tools for Nutrition & Fitness
You have cohort data, epidemiology, and then animal studies tend to get kind of lumped in together. And then you got like case studies and so on and so forth, right? And so all that stuff is valid. It's all valid. I think where I spend a lot of time on social media is, for example, I'll give you a great example.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And, well, my next thing was, well, a lot of non-essential amino acids, if you give them in the diet, they don't really raise non-essential amino acids in the plasma because the gut, liver extract a bunch of them. Glycine is different. If you give, there was a study looking at giving just one gram of pure glycine to
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And looking at the rise in plasma glycine in it, I think it went up – like I think the like native level of glycine in the plasma is something like 250 micromolar. And after giving a gram of it, it went up to like 400 micromolar. I'm giving my best estimate based on the graph I saw. And so then I got thinking, OK. OK. That's, I guess, possible if you have more glycine and proline.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I didn't look, I didn't see the proline data. But if you have more glycine and proline that's winding up in the plasma, not that they're being directed to those tissues, but since those tissues use so much of that amino acid, perhaps it does help. And then if you look at like whey protein versus collagen and the content of glycine and proline,
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Dr. Layne Norton: Tools for Nutrition & Fitness
I think collagen has like three to 10 times the amount of glycine and proline in it compared to whey protein. So am I ready to say collagen helps skin and connective tissue? I'm not because I'm still, you know, the study looking at connective tissue synthesis doesn't show anything. So the mechanism is incomplete, but there is a plausible possibility.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
at least they've shown that glycine can go up in the plasma from taking it in. And it is a big component of collagen.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Well, I think what they would say is like, there's because you're getting hydroxyproline in the collagen, in the collagen that you're taking that probably, I don't know how much hydroxyproline is typically in the diet, you know? Um, But I would say, again, I am a little bit nervous about like a lot of these subjective measurements of skin appearance and skin tightness.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I mean, I'm not saying faking data. I'm just saying that data is easy to get wrong because it is subjective, right? The more subjective things are, the more bias you introduce. So I hold open the idea that supplemental collagen could help with skin, hair, nails.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I'm not convinced by the data and I'm not going to tell people to spend their money on it just yet, but I'm going to stop short of saying that I think it's BS. And I've actually changed my tune slightly on that from looking in this day a little bit further.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Someone saying, well, you don't want to eat cruciferous vegetables because they have isocyanthanates in them, which can bind to iodine. And that is going to impair your thyroid function, lower your metabolic rate and cause you weight gain. And so. That's a pathway. That's a mechanism. Is it possible? I suppose it is possible, right? That pathway does exist.
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Dr. Layne Norton: Tools for Nutrition & Fitness
No, it's very, very low in the branched amino acids. The lowest in leucine of any protein source I'm aware of, I think it's like 2% leucine, which is like most – even like the worst plant-based sources of leucine are like 6.5% leucine. So like the worst sources of protein in the diet are still like three times more leucine than you get in collagen protein.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Eggs are going to be around 9% leucine. You know, beef, chicken, most of your animal sources are around 8%. And then most of your plant sources are 8% and under.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Like- By the way, not convenient for me either.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Iodine is important for thyroid function. Isocyanthanates do bind to iodine. You can take any food, even organic food, and you can find a compound in it. That if you fed it in a high dose, it would have weird effects, right? And so the question is not if you eat something, are there compounds in it that maybe activate negative biochemical pathways? The question is what is the overall outcome?
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Dr. Layne Norton: Tools for Nutrition & Fitness
Well, speak for yourself of being long-winded because I'm not. Honestly, I appreciate that. That means a lot to me. You know, I recognize how... you know, valuable your platform is and how many people want to be on it. And the fact that I've been asked to come on again, I really appreciate it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And to be able to have the opportunity to disseminate this information and not just talk about the studies, but talk about, hey, here's a here's a method of thinking. Here's a way to approach this stuff. And I mean, you kind of pointed out like I would love to be able to say, yeah, seed oils are bad. I'd love to give you that answer. I can't I can't do it. I can't make myself do it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because I look at the evidence and I'm glad you said spirited. I do feel like I do have some fighting spirit. But at the end of the day, I. I tell people, you know, I'm human. I've got my own biases, my own beliefs. Um, and I like making money like anybody, but I, and I like to be right. But at the end of the day, I, I want to help.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I believe that if I continue to execute on that mission, that, you know, financial stuff will take care of itself. And at the end of the day, I just want to be, want to be a net positive on the world. So thank you for giving me that chance.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so when these pathways are promoted versus let's see if we actually have randomized control trials in humans. that measure what we actually care about. And so we do have, like in that particular case, we have randomized control trials looking at, okay, cruciferous vegetable intake and thyroid function. And there's no difference in the outcome.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so what that says, and then no difference in BMR. And then actually people who eat more cruciferous vegetables actually tend to be a little bit leaner, but that could be a little bit healthy user bias. And they'd probably just eat less calories because they're more satiated, but it's certainly not going the opposite direction. Right. And so,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
The point is, again, if an outcome exists, there is absolutely a mechanism to explain it. But just because a mechanism exists does not mean you're going to produce an outcome. And I got exposed to this very early because I cut my teeth on the bodybuilding message boards back in the day where it was a bunch of nerds arguing with each other, mostly who had no background arguing.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But there were some actual like sports scientists and professors who would get on those every once in a while. This was before social media existed. And I remember I was in biochemistry class. This is 2003. And they're talking about how caffeine inhibits glycogen phosphorylase, which is a mechanism. And it exists. Caffeine inhibits glycogen phosphorylase.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so I made this post where I – on the forums and I said, well, we should be having caffeine after a workout then because it will help with glycogen resynthesis because it will keep glycogen phosphorylase from breaking down glycogen. And somebody came in and said, you're really like zooming in on a blade of grass instead of zooming out and looking at the forest, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And biochemists – I was guilty of this and biochemists by trade, we get very focused on pathways. But if you think about what caffeine does overall, activates the sympathetic nervous system, its function is to, like, you're liberating fuel. And some people, when they take caffeine, actually have a rise in blood glucose. So that is the outcome.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
is actually counter to what that biochemical pathway is. And so we've got to be really careful with how we promote these biochemical pathways. I mean, I did a really funny post on Twitter where myself and Joseph Sundell, I'm not sure if you're familiar with him. He's a cancer biologist.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And we were joking back and forth. I said, you know what? I bet I could like come up with a pathway to get people to eat poop. Like I can make a compelling argument for just eating poop. And then he goes, he's like, I'll take that bet. I'm like, okay, let's give it a shot. So I'm like, what is some of the most common compounds in human fecal matter?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And one of them is butyrate, right, which is a short-chain fatty acid produced by fermentation. Butyrate, so I did this post where I'm like, here's why you should eat poop to lose fat. Butyrate increases fat oxidation. I think it activates brown fat, increases insulin sensitivity, decreases inflammation. It's been shown to actually ameliorate the development of obesity in studies.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so I had all these PubMed ideas. Now, what I didn't tell people was those are all mostly in rodents, right? And it's giving an amount of butyrate that you'd need to eat about 50 to 100 pounds of fecal matter a day in order to get, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But that is very similar to a lot of the content that is out there, which is find isolated compound, scare people or promote it to be the best thing ever, and then link it to an outcome. And then sometimes you can tie in epidemiology with it as well to support whatever you want.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But again, like I'm not saying – I do things in my training and my nutrition that don't have randomized control trials to support, right? They don't really have anything to support. It's just – it's how I've kind of fallen into doing things. So that's okay. But what I wouldn't do is come out and say, what I do is the best thing ever.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And here's why, especially if there was human randomized control trials to the counter, that is the biggest thing, right? If we have human randomized control trials and they're going the opposite direction of a case study or an observation, there's a reason human randomized control trials, I scream about them all the time and why they're considered the gold standard of evidence.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
When we look at cohort data, You're just observing people. There's no intervention.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Sure. So cohort data, you're comparing groups, but you're not having an intervention. So you're tracking them over the course of however, what period of time. A lot of cohort studies like looking at cardiovascular disease, cancer.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Those are some of the classic experiments, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And you look at, okay, over 10 years, over 20 years, who gets whatever more often or less often, right? And then we try to figure out and calculate, okay, what's the effect and is this real? The problem is you have a lot of bias with those sorts of studies, meaning people don't do single habits. They don't isolate habits.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I actually put up a reel the other day from my appearance on Stephen Bartlett's podcast where he said, if I want to fix my diet, I go to the gym. Because a lot of people do that. If they're training in the gym, they don't want to waste their effort by having a subpar diet. Now, in reality, eating a healthy diet is more important if you're not going to the gym, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because at least you're getting something. But people do this habit coupling. And so it's really hard to disentangle those sorts of things. Now, the reason that human randomized control trials are important is if you're designing an experiment and you randomize What you are doing by randomly assigning people to groups, you're washing out that bias because.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
you can assume that whatever inherent characteristics that might be coupled to whatever you're going to try are going to be randomly distributed and evenly distributed across the groups.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Therefore, we say human randomized control trials are kind of what's needed to establish causation because by randomizing, you can assume whatever differences are observed between the groups are due to your treatment and not due to random chance or data artifacts. Now,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Randomized control trials, especially in nutrition, have very strong limitations, which is you can't do a randomized control trial for 30 years. I mean, I think the longest randomized control trial I heard about in nutrition is like two years long, right? And even then, it's not going to be a very tightly controlled randomized control trial.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I mean, and if you're talking about like the tightest level of control, like a metabolic ward study, Four, six weeks, maybe, because you're keeping people in food jail. And I think where some of this confusion comes from is I think people think that there's just like this pool of people waiting around to be selected for experiments. Like, yes, I'm ready. I've been waiting here.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
No, there are people like you, like me, like just the average person walking down the street who saw a flyer and goes, OK, I'll volunteer for that. And the more control you try to establish over their lives, the less likely they are to do it. And you probably got to pay them. You know, I don't know anybody who would do a metabolic ward study without getting paid for it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I mean, you're basically giving up four or six weeks of your life to go do that. And so while I love human randomized control trials for some things, they're not always appropriate. For example, if you're trying to look at heart disease and you want to do a one year human randomized control trial, looking at, say, saturated fat, LDL, cholesterol, those sorts of things.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Well, how many people have heart attacks within one year after age 60? I mean, you're going to look for differences between really small numbers, right? And the problem with that is you have no idea about their diet 40 years leading up to that. And we know, based on now the Mendelian randomization trials, that the risk of LDL is more of like a lifetime exposure risk.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It's not just in this narrow sliver of time. And so I love human randomized control trials, but it's also, I try to tell people Never turn your brain off. Just because something gets published in a certain journal, just because a certain researcher said something, just because it was a certain design, it doesn't make it infallible, okay? Science is perfect. Science is perfect. Science is what is.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But it's done by humans, and humans are fallible, imperfect people with their own personal beliefs and biases that And that's why I look at consensus of data first because, yeah, you could – maybe some experiments got faked or maybe they had – but when it's done over – let's take something like creatine monohydrate, right? You have thousands of experiments done over decades of time.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
in hundreds of different labs with many different funding sources in a bunch of different countries under a bunch of different conditions, it works, right? Like if you go to consensus and you type in, does creatine build muscle? It's like 92% yes, which is crazy.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I realize I've been on a long diatribe. No, no.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah. And I think the one other thing I'll tell people is I saw this the other day. I saw somebody post. I think it was a comment on one of my posts. I actually commented back. They said, you know, I just I know I can trust you. And I just whatever you say, I know I can take it to the bank. And I said, I appreciate that. But I am a flawed human like anybody else. please don't turn your brain off.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And one of the things I've really tried to do now in this stage of my career is I want to teach people how to think. Because if I just give you the information and I'm giving you a fish, great. But I'd rather you understand how I came to these conclusions. You can see my logic and how it tracks. And then you can start applying it elsewhere. And one of the things I say to people is I'm like,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
if you want a quick and dirty hack for knowing who to follow, try not to listen so much to exactly the information people say, but listen to how they say it. Okay. I was just telling you, I was on a podcast the other day where I said, you know, here's this study. I might butcher the details. And if I get the math wrong, if experts out there want to comment and correct me, please do that. Like,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
That is a way of talking about something where you're saying, hey, I could get this wrong or hey, I might be uncertain. That's very different than saying, you know, just hard, pure, you know, real experts don't really talk like best, worst, always, never. Like they don't really use words like that.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And one of my favorite phrases that I tell people, it's actually from an economist named Thomas Sowell. He said there are no solutions. There are only tradeoffs. And for example, you know, there's data out there that if you lower saturated fat, it may lower your testosterone.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But there's also data out there that saturated fat raises LDO, which is an independent risk factor for cardiovascular disease. Okay. Well, there's tradeoffs there, right? Like what do you value more? I would argue that probably the decline in testosterone isn't really physiologically meaningful for most people. But again, there's not a good or bad. There's tradeoffs.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I think when people get talking about biochemical pathways, one of the things I really try to hone in on is like, hey, there's not really good or bad biochemical pathways either. Like all these things exist for a reason. Like people, like one of the things popular is like, well, inflammation, inflammation.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I'm like, Hey, you know, like inflammation does some things that we really need to, like, you just don't want like no inflammation. Like it's actually important physiological process, right? Now you don't want it to run away for sure. And so again, I just give my PhD advisor a lot of credit of, he's like, know what you know, but always question yourself.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Everything, even the things we feel most fundamentally are true, because that is the job of a good scientist. I'll give you one more story and then we'll move to another thing. When I did my first experiment, well, actually, sorry, no, this has been like my 15th experiment because my first 14 blew. It didn't work.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, yeah. And again, very patient man, very supportive. I honestly cannot give him enough credit. And if you look at the people that came out of that lab, a lot of studs. So I did an experiment looking at complete meal with whey protein ingestion and how long the duration of muscle protein synthesis was.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because most people kind of measured at 60 or 90 minutes, like the snapshot postprandially for protein synthesis, looking for a peak. And we're like, is that really where the peak is? We don't know. We're basing this off of purified solutions. So let's do a duration experiment, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And my hypothesis was, well, however long leucine is elevated in the blood is going to be how long protein synthesis stays up. And when we got the data back on protein synthesis, protein synthesis had come up, peaked at 90 minutes and by three hours had come back down to baseline. And I went to run the plasma amino acids and I'm like, OK, well, this is what we're going to see.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And that's not what we saw. So plasma amino acids not only were still elevated, they were like maxed out or plateaued at the highest level they would be at three hours where protein synthesis was back to baseline. And so I said, OK, well, it's got to be mTOR signaling. mTOR signaling is going to be turning off. Or something's happening. Nope, mTOR signaling was still elevated, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And we saw this through phosphorylation of the binding protein for EBP1, which is a proxy for mTOR activation. And then I said, okay, well, maybe leucine isn't getting into the cell. Maybe that's why. So we looked at intracellular leucine, followed the exact path of plasma leucine. And so then I kept rerunning the plasma data over and over. I probably ran it five times. Right.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And Lehman finally calls me into his office one day and he goes, so where do we stand with this duration experiment? And I said, yeah, it's almost done. I just I got to run the data again because the plasma data has got to be wrong. And he I saw his like little eyebrow go up, you know, and he goes, why do you think that? Let me see your data. He goes, your standard air bars are good.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
This looks to be relatively tight data. How's your technique? And I'm going through like how I – all the steps to analyze plasmido acids. It's not like CSI, by the way, everybody, you don't just like take a pipette, put something in a centrifuge and all of a sudden you get back data. There's many steps in here.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so I showed him all that and he goes, you know, it sounds like you are trying to get the data to fit your conclusion. And what you need to do is change your conclusion to fit the data. And that one line. again, it just opened my whole world up to one. If I'm wrong, okay, cool. Like I care more about getting the right answer than being right. And that's why we were talking earlier.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I'm like, there's so much stuff that I just don't believe. I want to see 10, 20 studies before I go. Yeah. You know? And the other thing I'll tell people is, Hey, I don't plant my flag real strong very often. So when you see me do it, I'm not saying I'm not fallible, but if you see me do it, you probably should pay attention because I don't usually do that.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah. So we actually looked for this for years. So a few things. There was some other studies that supported that. We called it a refractory response. Actually, we didn't name it that. There was another lab named it that. Basically, that protein synthesis was becoming refractory to the signal for protein synthesis. So just for real quick, I'm going to try and explain this easily.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So protein synthesis, you know, this sounds like probably a very abstract thing, but it's how you make your body makes more protein. And whether it's in skeletal muscle, whether it's in the liver, whatever, you have your DNA, which is your genetic code, right? And then that gets transcribed to an mRNA. By the way, I'm leaving out a lot of steps here, but just bear with me.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
That mRNA gets translated by a ribosome into a polypeptide chain or a protein. So a ribosome is basically attaching to the mRNA and then based on the mRNA sequence is bringing in amino acids to match that sequence. So all the proteins in your body are coded for in your DNA, right? So when it comes to this process,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
There's a complex called EIF4F, which acts as a scaffold for the ribosome to hook on to the mRNA. And EIF4F, the formation of it, is basically rate-limited by the association of two proteins called EIF4E and EIF4G. And EIF4E is bound by a binding protein, 4-EBP1.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And when you stimulate, when leucine stimulates mTOR, mTOR stimulates the phosphorylation of 4-ABP1, which makes it unavailable for binding with EIF4E. It can bind to EIF4G. that EIF4F complex can be made, brings the ribosome onto the mRNA, and now it can read, it can translate it. So there's a little cellular biology lesson for you.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So another lab called it the, the muscle full effect. Basically the idea is like once you've initiated that signal, uh, it kind of runs and then it's done, right? And just pounding more amino acids into the system is not going to further stimulate. In fact, there was a study done back in, I think it was 2001 by, I want to say by Rennie, another very well-known protein lab.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And they infused essential amino acids for six hours and looked at skeletal muscle protein synthesis. And they found it went up and then came back down by two hours and then never went back up, right? Good experiment. Yeah, very interesting. So- We looked at a bunch of different things.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
The only thing we found that perhaps explained it a little bit, and I'm sure there's other labs that would argue with me on this. And again, this is in rat skeletal muscle, which, by the way, is a good model for human protein metabolism, but still. We looked at intracellular ATP levels and actually found that they were declining kind of in concert with the decline in muscle protein synthesis.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And muscle protein synthesis is an ATP-dependent process. But the process of protein turnover is energetically expensive. It's one of the reasons that protein has a higher thermic effect of food. And so our hypothesis was perhaps – By the effect of protein stimulating protein synthesis to start this machinery is energetically expensive enough that eventually you kind of run out of steam.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so you have the signal there. But it just kind of ends, right? Now, there have been other experiments like Jordan Tromelin just published a paper a few months ago that got a bunch of feedback. It was 100 grams of protein after a resistance training exercise and saw that it was basically – like a lot more of it was used than we thought would be used.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So what I tell people is I don't make big shifts in my opinions based on single studies.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It shimmies me a little bit, right? And even before that study came out, what I had said is I think protein distribution matters, but I think it matters much, much less than total protein intake per day. Because all we need to do is look at some of these resistance training studies with intermittent fasting, right? where people are eating all their protein in an eight-hour window.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And theoretically, you would think they would get less muscle growth, especially based on this refractory data, because less time to stimulate. But at least in the studies out of Grant Tinsley's lab, I think there's two studies that were very well done where we don't see that. Now, important to point out, they trained during their feeding window and they had three.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
They made sure they ate three high quality, high protein meals during that eight hour time. Right. So at least in that context, there was no difference in the amount of lean mass gained between intermittent fasting groups versus continuous feeding groups.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I don't recall specifically, but I don't recall an actual defined time.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I'm going to bring this back around to that particular experiment. So over time and when I left grad school, my position was that. It matters. Protein distribution matters. So I'll give you the straight down the line scientific answer and then I'll give you – if you inject me with truth serum, what I really think answer. And so we did an experiment, again, in rats.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
We fed them completely same diets, same total calories, protein, carbs, fats. But – Uh, in one group, they got that pretty much evenly across three meals and the other group, 70% of their protein was coming at their last meal. And then the other two meals were like 15% protein, 15% of their daily protein. And 11 weeks, again, 11 weeks out of a rat's life, rodents live 18 to 24 months.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Um, that's a big chunk of their life, right? Yeah. And we did see about a 5% to 10% difference in the weights of the hind limbs in terms of muscle mass.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Favoring equal distribution, right? Now, again, hard to repeat that study in humans, right? And for the duration it's done. So I came out saying, you know what? That's actually less than I thought we were going to – I thought we were going to find bigger differences than that.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because, I mean, if you're thinking about number of times you're stimulating protein synthesis, I mean one per day versus three per day, I mean shouldn't there be like a pretty significant difference there? And it was – I mean it reached the level of significance. But again, I thought the effect size was smaller than I thought. And so I kind of walked out saying, you know what?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Total protein intake is the most important thing per day. And then if you can distribute it relatively evenly, that's maybe the last 5% to 10%, right? And you've seen some human studies where it seems to matter. Most seem to show it doesn't really matter that much. Here's what I think. If you're measuring an outcome like lean mass, that doesn't change much in eight weeks, unfortunately.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It's very small differences. And so I think it's going to be hard to detect that. But what I'll tell people is if you're asking, can you build muscle intermittent fasting? Absolutely. Can you build a lot of muscle? Probably. If you are a bodybuilder, specific population, or if your goal is to be the most muscular, strongest human being you can possibly become,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I think you're probably better off not doing intermittent fasting just because those last that last five percent may make a big difference. And you're never going to be able to pick that out of a human randomized control trial in eight weeks. At least I don't think you will.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so, again, I don't have any human data to really back that up, but just based on what I know about signaling and the effects we saw on animals, that's kind of my recommendation. But most people don't fall in that category. Most people are just worried about, hey, I want to look good, build a little bit of muscle. Intermittent fasting is a perfectly fine tool for doing that.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I will say, you know, obviously we haven't studied some of the more extreme forms of fasting in terms of building muscle, right? Like the 16-8 has been studied previously. But like I'm thinking of a study that was done without resistance training, alternate day fasting versus continuous kind of normal feeding.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So the way they did it was they did – the continuous group was getting 75 percent of their maintenance calories per day, so in a deficit. And then the alternate day group was doing 150 percent and then zero, right? So you're getting an average of 75. And they actually saw differences in lean mass at the end of that study, the continuous feeding group.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
lost less lean mass than the alternate fasting group. So that's only one study and it didn't have resistance training. It's possible that resistance training could attenuate some of that stuff. But what I'll say is, you know, the more extreme forms of fasting probably aren't optimal for lean mass, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah. So I think this is where the rubber kind of meets the road in terms of straight down the line. The randomized control trials say this, but I still do something a little bit different. Right. Because the randomized control trials say protein distribution doesn't really seem to matter. Right. But again, you inject me a true serum. I think it probably does matter a little bit. Right.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Now, does it matter as much as total protein? Absolutely not. That is by far the biggest lever. But again, if my context is I want to become the most muscular, strongest human being I can be, which I do because that's where I compete, I'm going to distribute my protein probably over four to five meals per day, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So, well, it's summer right now. So kids are off of school. So we're usually getting up around like seven thirty, eight o'clock in the morning. And my first meal is usually within an hour. And then I usually eat within an hour of going to bed and then I'll have two or three meals in between those. So usually I have about four meals a day.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Sometimes I'll have five if it's just a longer day or just how my timing kind of goes or whatever.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I mean, sometimes they end up being like mostly protein or whatnot. But for the most part, there's a mix in each one. And usually around 50 grams of protein at a meal. Yeah. About 235 grams of protein a day. Some people would argue that, oh, that's more than you need. The research has shown that 1.6 grams per kg maxes out the response. Here's the thing.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And again, this is where like scientific experiments are big, blunt instruments. OK, they will tell you what not to do more often than they will tell you what to do. OK. When it comes to protein, my personal opinion, and this is just, I guess, a little bit of intuition based off of 20 years of studying this stuff.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
is that I don't know if there's an actual amount of protein that maxes out the protein synthesis response. I would bet, if I was a betting man, that it's kind of an asymptote. You're familiar with, yeah.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, so it's easier to explain if it's going towards zero. So an asymptote might be, okay, you start out, you have 10, then five, then two and a half.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Correct. So I'm trying to explain it because it makes more sense when people kind of go this way. you never reach zero, but it keeps getting incrementally closer on the other end. I don't think protein synthesis ever maxes out. I just think the increment of increase becomes so small that practically there's no difference and you wouldn't see a difference in outcome. Right.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so I think that, you know, one, you know, there's debate over is at 1.6 grams per kg, 2.4 grams per kg. I, and there's even been a meta regression that showed up to 3.3 grams per kg had benefits and, I think a lot of this is with protein synthesis, you're looking for small differences between small numbers. It's not a very sensitive analysis, to be quite honest with you.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And, again, we would never be able to pick out those differences. And I'm thinking about there was a study by Stu Phillips who, if people don't know who Stu Phillips is, he's the best researcher going in protein metabolism right now. But one of the best. Sorry, I don't want to tick anybody off. And he did a study probably 15 years ago where they gave people different levels of egg protein.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And they looked at 5, 10, 20, and 40 grams of egg protein. And their conclusion was that 20 grams of egg protein maximized the protein synthesis response. But that's because straight down the line, if there's a p-value of more than .05, you can't say there's a difference, right? But if you looked at the absolute difference between 20 and 40 grams, I think it was like 11%.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And if you look at the graph, it almost looks like the start of an asymptote, right? Now, this was one study, wasn't a huge subject number. But that's kind of where my personal thoughts land on it, that kind of also support this, okay, 100 grams at a meal could still be utilized, is I'm not sure if there's a max out. I think there's a practical max out where you get to a point where –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
hey, you're like slamming down 50 grams more protein for 0.0001% more protein synthesis. It doesn't make sense. But yeah, we'll never be able to – I doubt we'll be able to pick those numbers out in actual scientific experiments. And the other thing to keep in mind with this whole protein metabolism picture is we're really only talking about one side of this equation. So –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Net gain or loss of skeletal muscle mass is the balance between protein synthesis and protein degradation. And most of us protein researchers just kind of stick our fingers in our ears and go la, la, la, la when it comes to protein degradation because it's so incredibly hard to measure.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so, yeah, like when we start to put all that stuff together, it's like now this picture gets really complicated. So what I tell people when it comes to that kind of stuff is listen. You could really get into the weeds on this stuff. The big rocks are about a gram per pound of body weight.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If you want to really, for all intents and purposes, max out the anabolic response, you're going to be fine.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Right. I'm probably like, you know, real sticklers might be like, no, it's actually more like 0.7 or 0.8. And then it's, well, it's actually based on lean mass, which I agree with. But just for all intents and purposes, you could say...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
you know, your body weight, ideal body weight, whatever it is, that number is, is going to be very sufficient for maxing out muscle building for the majority of people.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, for sure. And I, I think I would tend to agree with her, you know, the process, because when you eat protein, You're not just going to start laying down slabs of lean tissue just for meeting protein. There has to be a stimulus, which is resistance training. Or some people would argue you could stretch really hard and get the same thing, which there may be some evidence of that.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
There actually are studies now where they like put people in like really kind of hardcore stretching for, you know, several minutes and they actually see hypertrophy with it. Yeah, very interesting. We could talk about those if you wanted. But the point is, either way, it's mechanical tension, right? So that's the stimulus to build muscle, to lay down lean tissue.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But the process of remodeling is probably beneficial for multiple reasons. So when you eat protein, like we said, synthesis goes up, degradation goes up, right? Because you're stimulating that process. You're stimulating protein turnover. One, that's relatively energetically expensive, all things being equal. So that's where the thermic effect of protein comes from.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because people say, well, it's the urea cycle and this and that. Most of those ATPs, you get back in different phases of that cycle. Really, in my opinion, the thermic effect of protein is due to that kind of activation of this futile cycle of you're building more protein, but then you're also breaking down more protein. And so part of that is you are remodeling. You are making sure that
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
That protein is higher quality in that tissue by continuously breaking it down and building it back up. And so I would probably agree with that. And then again, even if you're in a resistance training program where you're not really building much more muscle anymore, the process of remodeling is probably good for you, you know.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I would just say try to ally some of these concerns from people who are concerned about gaining too much muscle. So I have been lifting really hard consistently for 25 years. I am very comfortable with saying I train harder than almost anybody else you can possibly imagine. And anybody who has trained around me will back that up, back me up in the comments. I train very hard.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And in a shirt, I look like an athletic guy who lifts. I don't look like a monster, you know, like you might see pictures of me when I was a bodybuilding show and like very, very lean. And that looks, you know, over the top. But for the most part, I just look kind of athletic and I spent my entire adult life trying to get too big. Right.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So for most people, unless you're on performance enhancing drugs or you just have incredible genetics, that's not going to happen. And if it starts to happen, just back off on your lifting. Easy fix. So yeah, I think most people's concern with that is a little bit misplaced.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And the other thing I'll tell people is like, hey, some of these fitness, especially for women, a lot of these fitness models you follow, they show you certain workouts they do. They built that physique by lifting weights, right? And you're thinking that's a toned feature. Now, that person is actually pretty muscular, right? And so, again, especially for women, there are exceptions.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Some women have very great genetics for building muscle. They usually wind up in track and field, that sort of thing. But it's very hard to get too muscular for a woman. And what I'll say is like, you know, typically muscle looks good and fat is what makes you kind of look bulky, you know?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So again, I don't want to paint with too broad of a brush, but I would say that you don't really have too much to worry about when it comes to, to getting too muscular.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And that's, and that's again, where the rubber meets the road with what is practically doable. Cause there've been some of these like circadian rhythm studies that suggest, well, maybe early time restricted feeding is better than late time restricted feeding. Um,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
The more high-quality, more rigorously controlled, randomized control trials that are coming out now seems to show that it doesn't really make a big difference. And some of the – again, the measurements you use matter, right? So there was actually a very recent study where they looked at 12 weeks. They provided all the food to participants, equal in protein, calories, the whole deal.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
The only difference was one group was eating 80% of their calories before 1 p.m., and they had an eight-hour feeding window in total. The other group had a 12-hour feeding window and were eating over 50% of their calories after 5 p.m., I want to say.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so really like based on some of the chrononutrition stuff we've seen from some of the lesser well-controlled trials, they were expecting to see differences in like glucose metabolism and whatnot. And they just didn't really see a difference in anything. And the only – I think the only thing they saw a little bit of a difference was in fasting blood glucose. And here's what I tell people.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
When you see a difference in fasting blood glucose but not HbA1c, you're looking at a transient difference. And what I mean by that is HbA1c is such a great measurement because it's an area on hemoglobin that can be glycosylated. And so that is very dependent on what is your overall concentration of glucose in the blood over a 24-hour period of time.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
because it's exposed the entire time it's in your bloodstream. So whether you're getting glucose spikes at meals or you have higher fasting blood glucose, it's going to be very reflective of the overall 24-hour area under the curve, right? So why do some of these studies see a little bit better improvement in lowering fasting blood glucose, whereas HbA1c doesn't show up? Well, think about it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If somebody has early time-restricted feeding and they finish most of their food intake before 1 p.m., They have an extra like six, seven, eight hours that they're not hardly eating anything. It doesn't surprise me that the next morning, because they've technically fasted for longer, you have a lower blood glucose. Now, I can't really back this up straight up because nobody's ever measured it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But that, I think, is a logical explanation while you see some of this stuff. And that's why I tell people the measurement you take really matters. I think fasting blood glucose is a useful measurement. But I put much more value on something like HOMA-IR, euglycemic clamp, or – HBA1C. So anyways, I think the early versus late time restricted kind of doesn't matter too much.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So again, we're rubber meets the road in practicality versus what hardline research says. So I am not real convinced at all that it really matters when you eat your carbohydrate intake.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because my bias has been validated, I can leave now. So I really try to get people focused on the stuff that matters the most, right? So this is, if we're worried about carbohydrate timing... Even if there are differences, we are zoomed way in on the blade of grass, right? We're not zooming out all the way.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I think, hey, if somebody likes to eat more carbohydrate in the morning and that fits their lifestyle and that is easy for them to continue to do, then I would say do that.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So there are no solutions, only tradeoffs. Right. And when it comes to carbohydrate intake, you'll hear people say the data is all over the place. OK, in terms of like timing and how people feel. So I feel sleepy after I have carbs. Some people have I feel great after I have carbs. I'm ready to go left. I have a big carb meal before I go left. You know, it seems to be all over the map.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Now, here's the thing. What I'll tell people. Because when people ask me how I eat, people have wanted me to do a full day of eating video. And I've kind of put it off for a while because I'm like, so much of the stuff I do, I'm not going to give you guys a citation for. And I know you're going to want it. And some of the stuff I do, because I just like doing it that way.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I grew up in the era of bodybuilding magazines where they said you've got to have a big carbohydrate intake and a big meal before you go train and a big meal after you train. So guess what I did? I got in the habit of eating like that and it still sticks to this day. I don't try to tell people it's better doing it that way.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Plenty of people have told me, hey, I don't feel good with a lot of my stomach when I go train. Or if I have a carb-heavy meal in the morning, I feel tired. The data doesn't really support that in terms of like on an average response. But if you know that you feel that way, then by all means avoid, right? Like there's – I remember one time I –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I used to go to a massage therapist in Tampa who would do cupping. And there's really no data to back up the efficacy of cupping. Is that right? Yeah, not much. But she did it. I liked the way it felt. And I'm like, OK, whatever. So I posted a picture of me flexing one time, you know, and there's the cup marks all over. And everybody's like going crazy, like, how could you do this?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I'm like, hey, hey, hey, hey, wait a second. I never said this does this. And I never made any claims about it. She does it and I like the way it feels. I'm not saying it does anything. Actually, one of the things about being a scientist is like now I'm impossible to placebo, which is really annoying because I would love to be able to placebo myself a little bit more.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because placebo effect is powerful. It's powerful and it's one of the – I was telling you earlier before we started filming. I'm like it's one of the reasons I just don't believe a lot of stuff because I know how powerful the power of belief is. I mean you had Sean Mackie on here. Your belief is about pain. Change your pain, like actually change how much pain you get.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It changes your pain experience. So one of the things I've become big on recently is, hey, what happens in the mind affects the body. What happens in the body affects the mind. So just because I don't have a randomized control trial to support something, if we know the RCTs don't say it's worse, right? then you do whatever you like, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I think a lot of people get bent out of shape when I say, well, you know, when they control the variables that need to be controlled, there's no difference between intermittent fasting or just regular old calorie restriction or there's no difference between low-fat diets and high-fat diets. What people hear is low-carb sucks. Intermittent fasting sucks. He said they don't work. No, no, no.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
This is great. This is great news for everybody. It means you have all the tools at your disposal and you get to pick the one that fits in your lifestyle best because that is what makes the difference is what your overall lifestyle looks like. And we have way too many people. worrying about the minutiae who just don't even exercise on a consistent basis.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So they don't sleep well on a consistent basis. So they don't manage their psychological stress well, or they try to be perfect with their nutrition and they fall off the deep end. And what I'm saying is like, no, like be imperfect, but be consistent with what you do. Right. And so for you, obviously carbs at night have not made you fat.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Like I have eyeballs, so we can just dispel that myth right now.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, I think how you say it makes all the difference, right? And even take somebody I've had conflict on social media with, which would be Paul Saldino, which when he would say something like, well, I cut vegetables out of my diet and I felt like my eczema got better. OK, that's your experience. You can't go on average. That's definitely not reflected in the research, you know.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But, hey, if you know that you did this thing and you felt better, that's fine. But how we're overgeneralizing to the population is the problem, right? And so I think – I mean, again, I'll say, hey, I calorie cycle a little bit, which, again, you can do using the app, right? You can change your days and whatnot, give you more calories some days, more calories other days.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I was – I showed a screenshot of it one time and somebody goes, so why do you do it like that? Like is that because it's better this way for like muscle growth and fat loss? And I go, no, because I had a –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
a get-together with friends on Saturday, and I knew I was going to have a couple beers, and I knew that there was going to be some fatty food, so I put 4,000 calories on that day and less the rest of the week. And they're like, that's it? That's your reasoning? I'm like, yeah. Compliance is the biggest one. I will tell people, I'm like, The reason that I – and we talked about this earlier.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Like I have never used performance-enhancing drugs. I've never – even when pro-hormones were leaveable, I didn't use them.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
No. And like my testosterone, even from like age 18 when the first time I had it measured up until like even a year ago, the lowest it's been I think has been like 750 and the highest it's been was like 1050. And so I obviously don't need it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So the reason that I've been able to have so much – and I get the skepticism. I really do. So many people say – I mean look at how many people are out beating their chest saying they're drug-free and then it comes out that they weren't, right? But I have been brutally consistent for 25 years.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
In 25 years, the longest I ever took off of resistance training was seven days and it was after I won world championships in 2022 for M193KG. So I've been able to be really consistent with my training. And I always give this comparison of – I think it just really highlights how powerful consistency is. And it relates back to my favorite quote I've ever heard.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
The magic you're looking for is in the work you keep attempting to avoid. The work is the hack. And I liked what our friend Peter Attia said this when he was talking about biohacks and why I didn't like the term biohacks. He said, I don't like that it occupies so much mind space, right? You get people really focused on the minutiae, which is fine if they're already doing the big stuff.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If they want to kind of level up a little bit, cool. For me, minutiae is where I live because the difference between me winning a powerlifting meet and me losing world championships is 1%, right? But for most people, we just got to get them consistent. If I said, Andrew, I want you to become the best three-point shooter you possibly can be, but you can't get any coaching.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You can't even watch any tutorials, right? But all you did for 10 years was go out and shoot three-pointers for two hours a day. You probably won't go to the NBA, but I bet you'd be pretty good at three-pointers, right? And I feel like if people could just get that message and internalize it more. No, it's not that you didn't have your carb-to-fat ratio perfect.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
No, it's not that you ate your carbs at the wrong time. No, it's not that you didn't get exactly this much protein. You just stop being consistent. You stop doing it. Yeah, you were really consistent Monday through Friday. And then Saturday and Sunday came. And you blew out. Right. Like if I'm consistent with my budget Monday through Friday, but then I blow it on the weekend. Hey, guess what?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
That weekend money still counts and calories are the same way.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I'll usually do like a five minute warmup on the bike before I train. And then I will, um, I will also make sure I get at least 10,000 steps on average per day. Um, I usually average more closer to like 11,000, uh, but I don't do a lot of purposeful cardio. Now, what I will tell you is my average heart rate in lifting sessions is about one 40 to one 50. Um, so, uh,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
if the definition of cardio is that, then I'm getting cardio. And actually when we, when I've had, you know, most my markers of metabolic health assessed, I'm very metabolically healthy. I've got good, actually it was funny. I just competed at nationals in late May and won. So I won. And actually again, very cool kind of side story.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You, we talked about the injuries I've dealt with and, and so I'm 42 now and, It's been an eight year journey. And I mean, going from I've had back pain so bad, I couldn't even get up the floor, needed a cortisone injection in my spine at one point, just be able to stand up.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
and multiple hip injuries a lot of chronic pain i dealt with and i'm very proud of myself that i never gave up because in my heart of hearts i felt like i haven't hit my last pr yet and at nationals this past year i actually set a national deadlift record for my age and weight congratulations um it was actually an unofficial world record and qualified for world championships
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But the – one of the team USA coaches, his name is Matt Gary. Him and his wife Susie are like – in evidence-based powerlifting, they are the goats and they are – there is no better game day coach to pick attempts than Matt and Susie Gary other than maybe my coach, Ben Escrow. Shout out to Ben. But – They were at the meet and we've known each other for 15 years.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And the next day I came down into the lobby and they're down eating breakfast. And Matt's like, your ears must be burning. We were just talking about you. And I'm like, oh, what? He goes, you know what I'm impressed with? He goes, your cardiovascular fitness. And, you know, powerlifting meets nine lifts, right? You get three attempts on squat, bench press, deadlift.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so I kind of like looked at him where he goes, we were there between warmups and finishing. It was about four hours. You never sat down. You were yelling the entire time. You're talking the entire time because I'm a very extroverted, active person. Then when I'm firing myself up, it comes out very extra. He's like, you're yelling the entire time and you never were tired.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And again, when I look at my heart rate and I was at the meet, I think the average was like 150 or 160. And so, you know, some people would not consider that cardio, but I would say my cardiovascular system does all right.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I've observed that exact thing. When I went through my first divorce, I was also getting I was also involved in a lawsuit with a company that I used to own a portion of. It's a very long story, ended up having a good ending for me. And all that stuff kind of resolved itself. The divorce, the lawsuit, everything resolved itself in about a six week time period.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So everything you just mentioned would fall into the category of evidence. Everything that we can observe is evidence. But I think what people really struggle with is the idea of different levels of quality of evidence. And if I had to put myself into a group, I have definitely been on the side of, well, there's a case study in this journal and we're going to try that now because it must work.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
As soon as it resolved, I got sicker than I ever had been in my entire life. I got the actual influenza. I tell people after that experience in 2018, I go, here's words I'll never use again. I think I might have the flu. No, you know. After you've had it, for sure, you know. And I mean, it – but it was like my body had just – maybe it's a little bit of woo, but it was like my body –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I dragged it across the finish line and then said, okay, we'll see you in a couple of weeks because we're taking a break.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
We see this with pain too, right? Like, um, you had Sean Mackey on talking about this stuff where, you know, I forget who was talking about this. I remember listening to a podcast with, it wasn't him, but it was another pain expert. And they said, um, Because your beliefs about pain, your stress level, your sleep, your psychological milieu actually matter in terms of your pain experience.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
In fact, the single biggest lever I've pulled to get me consistently training and pain-free was becoming more relaxed and less stressed out all the time and managing my psychological stress better. You know, when you're not vibrating and spun up all the time, your body has... Again, this is a little woo-woo-y, but I think you have more energy. I mean, if you look at... It makes sense.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I read something from a PhD in psychology who said, stop thinking about your problems. The problem is you're thinking about your problems too much. Thinking about it doesn't solve them. And just ruminating on them makes it worse. And actually, again, if you look at pain literature...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
fibromyalgia chronic fatigue syndrome very close ties to psychological stress and we were talking earlier about like if you look at the the data on mortality cardiovascular disease cancer on and with aces scores which is adverse childhood event scale so zero being best you were loved as a child that's sort of that you had no real big worries 10 being basically abused and
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
There's like a very, I don't want to say very tight, but there's a dose response of ACEs scores on the risk of mortality. So what happens in the body affects the mind and what happens in the mind affects the body. And we were talking about with pain literature what happens in the mind affects the body in your pain experience. And even just something like sleep.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
There was a study done where they looked at military members and they had eight hours of sleep versus four hours of sleep and they looked at the risk of acute injury. 236% increased risk in the people getting four hours of sleep versus eight hours. And now here's where people get this wrong. Somebody reached out to me and said, well, I got four hours of sleep last night. Should I? No, no, no.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
One bad night of sleep doesn't do that. Sleep is a cumulative effect. Just like if you have a week's long worth of bad sleep, but then you sleep 12 hours on the weekend, you're not making up that sleep debt. It's more about what you're doing time over time.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Exactly. And so this actually brings me to – I know we kind of have gone down the rabbit hole here. But when you look at – Ben Carpenter did a great example of this. He has a good social media account. He had a jar of like blue marbles and a jar of green marbles. He said, let's pretend that this is all junk food. These green marbles are all junk food, ultra-processed.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And or, you know, my friend tried this and they said it worked, so I'm going to try it. And then I've also gone to the group of, well, there's no human randomized control trial, so I don't believe it. And I think now, you know, I'm 42 now and I've been doing this for two decades. I think where I'd fall into is it really depends on how the individual is talking about the evidence.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
This blue is minimally processed whole foods, right? If my diet is mostly junk and I add one good meal and he puts a blue marble in the green, did it change things? No. And everybody knows that, right? Like if you eat mostly a junk diet, you have one salad or one good meal, it's not going to change things.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So why does everybody think if we take one from here and put it over here that it drastically changes things? Because it doesn't. It's about what you do consistently over the course of time. And so, um, speaking of, we're talking about the mind affecting the body, but then the body also affects the mind. And so there was just a study published.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I just covered it on my, on my channel where they took men with general anxiety disorder and major depressive disorder, and they had them resistance train two times a week for 25 minutes a session, 50 minutes, total eight weeks. It's not much training. I think it was like six hours and 40 minutes of total training over the entire two months.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Now, in statistics, you're familiar with an effect size, which is basically how meaningful is an effect, because you can have a significant effect that isn't very meaningful if you have enough subject number. So when we say things like an effect size, 0.2 is considered small, 0.5 is considered moderate, and 0.8 is considered large, anything above 0.8. SSRIs are typically in the 0.3 to 0.5 range.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I think in like best case scenarios, they get up around a 0.8, 0.7, 0.8. The effect size for resistance training two times a week, 25 minutes a day for eight weeks was a 1.7 on major depressive disorder. Wow. Anybody who's a scientist out there, if they hear effect size of 1.7, they do exactly what you did. Their eyebrows go up and they go, are they sure that's right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You don't see effect sizes like that very often. And I want to be very clear. I'm not saying do resistance training in place of SSRIs.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
They hadn't trained before. Yeah, they were healthy or… I actually don't know the specific characteristics, but I knew they were coming from like not training right now. Hey, like, listen, both these things can be true. Maybe somebody needs to get an SSRI because like depressed people don't even want to get out of bed a lot of times. Right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So getting them to the gym, even if they know it's going to help them is a hard, it's a hard swing. So maybe coupling that, but, That's just resistance training. And that affects this, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I think one of the biggest revolutions we're going to see in science is the broad application of biopsychosocial across a bunch of different disciplines and stop thinking about, well, your body's a bag of meat and it's attached to your brain. And if you poke the bag, punch the bag, burn the bag, cut the bag, brain goes owie.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And I think we're going to start thinking about things much differently. And I think it's going to open up a lot more in science. And in fact, honestly, if I had to go back and do a PhD again, it would be in some sort of like psychology or whatnot. Because I just think there's so much untapped in that realm. And I was actually talking about this with somebody the other day. And it's pure anecdote.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I'm completely speculating. I have yet to see an interview with somebody who's in their 90s or 100s who sounds really stressed out. They're mostly like DGAF, right? And when you ask them what they did, most of them say, oh, I drink wine every night. The one lady I remember, she was like 110. She's like, yeah, I drink Dr. Pepper every day or whatever.
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Dr. Layne Norton: Tools for Nutrition & Fitness
It strikes me that – and again, genetics matter. Their lifestyle matters. I'm not saying any of that stuff doesn't matter. I don't see, at least in my experience, people who make it old age, they're not usually very spun up all the time. I haven't observed that. I don't know if you've seen similar observations.
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Dr. Layne Norton: Tools for Nutrition & Fitness
OK, so as you can probably imagine, I get sent a lot of stuff for people to like, oh, debunk this. And a lot of times people will send me things and I'll go, hey, this person said this is their opinion. That's fine. Like I may disagree with their opinion, but I'm not going to like rake them over the coals for them saying this is an opinion or this is my personal experience. That's evidence.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And that's the lesson there is we're not saying that that stuff doesn't matter. He would have gotten better results if he hadn't smoked, if he had paid more attention to his nutrition, that sort of thing. But we have to keep in mind, what is the hierarchy of importance and the power here, right? And so- I'll give you an example.
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Dr. Layne Norton: Tools for Nutrition & Fitness
We're going to zoom in on the blade of grass, but I believe it relates back to this conversation we're having. So we know creatine works because we've got thousands of double-blind placebo-controlled trials showing that creatine works, right?
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Dr. Layne Norton: Tools for Nutrition & Fitness
But there was a study where they gave people creatine or didn't give them creatine and then randomly told them if they got it or not, meaning you had people who didn't get creatine, got creatine, who didn't get it, told they didn't get it, people who
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
got it told they got it and people who got it told they didn't get it and what they found was the results and i forget what they actually specifically measured but the results basically were like not what they got what they told them okay now people will misinterpret that as well see creatine doesn't work no no it works it just means your beliefs about what creatine does are more powerful than what it actually does just like actually there's a similar trial with caffeine
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Dr. Layne Norton: Tools for Nutrition & Fitness
And I'm thinking about – there was a study. I don't have the specific citation, but they had two groups of men train drug-free. One group they told they were getting steroids. That group gained significantly more strength and muscle mass. Now – I would argue that's probably because they're going into training sessions believing that they can train harder, believing that they will recover better.
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Dr. Layne Norton: Tools for Nutrition & Fitness
But that goes to show the power of placebo and the power of belief. When I say placebo, people think what I'm saying is you're lying about your experience. That is not what I'm saying at all. I think your experience is probably quite valid, right? What I'm saying is it may not be due to the thing you think it's due to, but your beliefs about the thing.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And so where I get really focused is let's do the big stuff, right? Because so many people are so worried about little stuff. And one of the things I'll tell them is, Hey, I have no data to back this up, but my intuition tells me that the amount of stress you're spending on these small variables is probably killing you faster than if you got those variables wrong.
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Dr. Layne Norton: Tools for Nutrition & Fitness
It's low quality evidence, but it is evidence. I think I kind of fall in a line of I ideally want to see human randomized control trials, but. There's also, as you mentioned, practical limitations with how things are implemented. And I think one of the things that gave me a very unique perspective was the fact that I was doing my PhD in nutrition after I did a bachelor's in biochemistry.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And if we could just focus on the big rocks first, and if we can pick up some pebbles after we get the big rocks, great. But don't drop the big rocks trying to pick up pebbles.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah. So you define failure the way I define failure, which is you cannot take the weight through another concentric repetition without breaking form. Um, Reps in reserve would be an RIR of one means you stopped one rep shy of failure. RIR of two, you stopped two reps shy of failure and so on and so forth, right? And so I would define those that way.
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Dr. Layne Norton: Tools for Nutrition & Fitness
This is going to generate a lot of discussion in the comments. I can't wait to see it. So I'm going to cite quite a bit of work from my powerlifting coach, Zach Robinson, because he is at FAU, just finished his PhD and did a lot of meta-regressions and meta-analyses on this exact topic.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So I had that mechanistic understanding. And then I had an absolutely wonderful PhD advisor, Don Lehman, who just – shout out to him – got a Lifetime Achievement Award by the American Society of Nutrition 20 years too late. But he was just incredible at being able to understand the small things – But how they impacted the big things and what it looked like overall.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So I'll give you the answers first that are straight down the line scientific answers, and then I'll explain things. For muscular hypertrophy... You need to get close to failure, but you probably don't need to train to failure to maximize hypertrophy, but you got to get pretty close. You can be stronger, but to maximize strength, you're probably better off not touching failure very often.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So there are a few studies now looking at this, showing that – I think there was one study recently, and I can't remember the exact details, but I remember it being pretty well designed –
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Dr. Layne Norton: Tools for Nutrition & Fitness
And the takeaway was hypertrophy was similar between the groups, but the group that went to failure or stayed a few reps shy of failure actually got stronger compared to the group that was taking most sets to failure.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And practically, that may be a benefit of stopping shy of failure, right? But yeah, they control for those variables. So when we talk about volume... The way we define that is essentially number of hard sets, which a hard set would be a set close to failure. The general consensus is within five reps of failure is considered a hard set. Now, what I will tell people is that may not sound like much.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Most people have never truly pushed themselves to failure. OK, and I'll. I'll give some practical examples of me. So my best set of squats ever, I did 530 for 10. This was a long time ago. Yikes. When I finished that set, somebody had to come save me because I couldn't fully lock out my lumbar and I couldn't get the bar on my right side all the way back up.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So I had to run over in the gym and help me. After that set, I laid down and I physically hardly could move for about 15 minutes.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Yes, do as many as you can. Your family's been kidnapped. If you don't get these 10 reps, you're – All those mental games. That sort of thing. And I mean I was done. You know what I mean? And so one of the things I'll tell people is the first five reps of that set were still hard. They still felt hard, right? And so people will say, oh, you stopped a rep or two shy of failure.
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Dr. Layne Norton: Tools for Nutrition & Fitness
You're training like a – so you're telling me – If I stop two reps shy on that one, that that's an easy set because it's not. I can tell you that. And the reason I'm giving this background is because in research studies where they have people who are like – beginners or intermediates, and they ask them to rate their RIR, they tend to underestimate their RIR, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So they'll say, during a set, say your RIR, and they might say two. And what they find is when the researchers push them to true failure, yell at them, crank the music, get them really psyched up, they get five more reps than they think they'll get on average, right? So most people, if you've never actually taken things to true failure, you actually probably don't know what it is.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I do think it's useful to train to failure at times.
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Dr. Layne Norton: Tools for Nutrition & Fitness
It's like a conductor looking at a symphony, right? And understanding how the trumpet sounds affects everything else, but then not getting so tied up in that that he can't hear all the music, right? And he was so good at that and was so good at getting me to think that way.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Being strong is fun. So, again, for hypertrophy, it doesn't seem to matter if you take every set to failure or stop a couple reps shy. I would argue that. Probably you'd want to leave most reps – most sets shy of failure. And if you're going to take one to failure, take the last set of an exercise to failure because then you can get whatever benefits might be there.
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Dr. Layne Norton: Tools for Nutrition & Fitness
But if you take the first set to failure – I mean imagine if I did that like set of 10 with 530 on squats as my first set to failure. What am I going to get the next set if I try to do 530? I can tell you based on how I felt, maybe three reps, maybe, you know? And so your performance is just going to really drop off a cliff.
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Dr. Layne Norton: Tools for Nutrition & Fitness
If you're going to true failure on like a compound exercise, isolation is a little bit different. And so I would say, whereas if you, you probably could have done like sets with, you know, six, seven reps for multiple sets and then have gone to failure on your last one, right? Now, it may seem a little bit counterintuitive. Why would it be the same for hypertrophy but different for strength?
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Dr. Layne Norton: Tools for Nutrition & Fitness
Well, with strength, you also have to think about stimulus to fatigue ratio because fatigue will mask strength, right? And I know this because I've – like when I overreach for powerlifting competitions, which is basically like we're taking me a little bit past my point of what I can recover from.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I mean, I've had literally before nationals in 2017, I was warming up on deadlift in my last heavy deadlift session, like 10 days before the meet. And I went to pull my final warmup, which is 585. And I couldn't budget off the ground. I was so tired, sore. I couldn't get, it was like, I couldn't get my body to do what I wanted it to do. 10 days later, I pulled 716.
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Dr. Layne Norton: Tools for Nutrition & Fitness
It's amazing what fatigue will mask. And so if you're always training to failure, you're going to be training under pretty high fatigue circumstances. It doesn't really matter for muscle growth because it's really just about doing enough hard sets and putting that mechanical tension on the muscle. With strength, you also have to think about like what is the most pure form of strength?
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Dr. Layne Norton: Tools for Nutrition & Fitness
It's force production, right? And force is mass times acceleration. So you have a mass component. You have a speed component. And so this is actually Zach Robinson and his company, Data Driven Strength, who I've been coaching with for three years. I heard them on a podcast and – he was giving his hypothesis of how to optimize strength in a powerlifter.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And I remember thinking, I really like the way this guy is thinking. He's thinking outside the box and it makes a lot of sense. So one of his things was, if you're training close to fatigue all the time and the goal is strength, think about what that means in terms of your force production. So let's say you do a set of eight reps, right?
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Dr. Layne Norton: Tools for Nutrition & Fitness
And so I think where people out in the landscape trying to dissimilate this really struggle is they don't really know, well, this person decided to study and they equate that as evidence that's equal with any other evidence, right? And as a researcher, you know, not all evidence is created equal. Not all journal articles are created equal.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Your first few are pretty fast, and then by the end, they're pretty slow. The load hasn't changed, so what happens to your force production? Your force production is going pretty far down. He said, I don't really want my athletes grinding reps in training. I want them to hit some heavy singles and doubles and triples because they need that because that's a skill.
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Dr. Layne Norton: Tools for Nutrition & Fitness
You have to have those neurological – everybody has done this where they go, well, I hit this for 10 reps and here's what my one rep max should be. And then they go in and get stapled with it, right? Because it doesn't necessarily translate because a one rep max or the purest form of strength is a very specific skill. If you've never trained it, it's very difficult to get accustomed to.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So we want to hit some – his idea was in workouts, we're going to hit a heavy top set, heavy single, double or triple or whatever it is. And then our back offsets, instead of taking those close to failure, instead of doing, say, well, we'll do 75% of your training max for sets of eight and have you getting pretty close to failure.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Instead of doing three sets of eight, why don't we just do like six sets of four with that weight? Because now you're doing those first four reps, which you can move that weight faster. You're having greater force production and creating – The good stimulus, but with less fatigue. And so, again, that was kind of the hypothesis. And he did a meta-analysis, meta-regression that supported this.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And now some of the randomized control trials have come out and shown something similar. And in my experience, I was honestly shocked at – because he had all kinds of stuff to deal with when he first started training me because I still was dealing with a lot of back pain, a lot of hip pain. I hadn't really gotten that under control yet.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And when I got ready for Worlds in 2022, which I think we did our first podcast like the week after I had won Worlds – I worked up to being able to do like two or three hard sets of squats a week and deadlifts. And that was all I could do. That was all my body could tolerate before I get pain.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And so we did a lot of low load, relatively low, low for me, you know, 60 to 70% one RM for low rep number sets, but trying to move it as fast as possible. to keep that pain under control for me, but to get the stimulus.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And I was shocked at how strong I got because before in 2014, 15, when I was winning open national titles, I mean, I was doing 15, 20 hard sets of squats and deadlifts a week and way more for bench press. And so I always thought, well, that's how much I need to get to that level of strength. And even now, like, so we've been able to keep progressing it. Now I'm doing probably more like
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
six, seven harder sets of those exercises per week. And I'm basically back to the strongest I've ever been doing way less sets. And I think a lot of it is we have learned to find the sweet spot with managing that stimulus to fatigue ratio. So all that to say, if your goal is building strength, it's mostly about doing enough like heavy lifting that you actually do get stronger and
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Dr. Layne Norton: Tools for Nutrition & Fitness
And I mean, honestly, people who don't have a research background, it's hard to unpack this stuff. So What I would say is you have to be very careful with people who cite studies. And one of the things I'll say, too, is there's nothing more dangerous than somebody who's read a biochemistry book because they're going to see pathway, biochemical pathway. There must be an outcome.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And then if you want to train closer to failure, you can, because again, most of my audience isn't trying to be a power lifter, right?
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Dr. Layne Norton: Tools for Nutrition & Fitness
And so this would be the protocol. There we go, protocols. Little plug. This would be a protocol for probably not necessarily like growing the most muscle mass but getting stronger because you're not training so close to failure. But obviously you're trying to move, as Zach says, whatever that given load is, you want to move it as quickly as possible.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so – and there's actually also data to show that like if you train slower purposefully, that it's not as good for strength. So they actually – there was I think a meta-analysis recently where they looked at either – Concentric repetition of more than two seconds or less than two seconds and saw strength outcomes were better in people taking less than two seconds to complete a rep.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Interesting. So, I mean, we do use some tempo training in my training, but it's mostly... Because like me doing a slower tempo squat, if my back starts acting up, I can do some squatting and not really hit that pain trigger as much. But I'm still trying to move the concentric as quickly as possible. And so I don't know about that.
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Dr. Layne Norton: Tools for Nutrition & Fitness
It doesn't matter how slowly you move the concentric versus how fast you move it. But yeah, what I would say is when it comes to building muscle, really the world is your oyster. The research really shows – Machines versus free weights. Low reps, high reps. Low reps, high reps, going to failure, stopping a few reps shy. It all builds the same amount of muscle for the most part.
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Dr. Layne Norton: Tools for Nutrition & Fitness
But you have to work hard. But you got to work hard. Yeah. You got to be consistent with it. Obviously, like the theme of this podcast, right? But... you can do it anyway. And if we look at the, I mean, obviously anecdotal, but if we look at the history of the Mr. Olympia is they all train very differently.
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Dr. Layne Norton: Tools for Nutrition & Fitness
You know, I mean, Ronnie Coleman, I mean, I'm sure you remember when the unbelievable came out, the D his DVD back in like 2001, where he's tossing around 200 pound dumbbells and he's doing seven, 800 pound squats, 600 pound front squats. And everybody's just looking at this, like my God. And then you watch somebody like Phil Heath train, who again, one of the greatest Mr. Olympia is of all time.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Phil mostly did, machines, but he built obviously a great amount of most of the people will say, well, they're on steroids. All those guys.
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Dr. Layne Norton: Tools for Nutrition & Fitness
That's all. Trust me. It's an equal playing field because they're all doing, they're all doing it right.
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Dr. Layne Norton: Tools for Nutrition & Fitness
There is no hypertrophy rep range like people used to think. Oh, it's like six to 15 reps is hypertrophy. Now, I think practically it makes sense to do a lot of your sets in that range. Because if you're trying to do 30 reps getting close to failure, I mean, gosh, I'm going to run out of breath if I'm doing any kind of combat.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So outcomes are what we really care about at the end of the day. And when I say outcomes, gaining muscle mass, losing fat mass, Risk of cardiovascular disease, insulin sensitivity, cancer. But these are hard outcomes, right? And those outcomes are the summation of dozens, if not hundreds, if not thousands of biochemical pathways all summing up to an outcome.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Could we also perhaps- But I would say that goes for anybody, quite frankly.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I think you can stick with those. I think, you know, the whole concept of muscle confusion... Muscle knows tension and how long it's under that tension and for how many sets it's under that. It doesn't it's not like, well, this is a I can tell that this is an incline bench press versus an incline dumbbell.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I mean, you know, you might move through different ranges of motion and whatnot, but the tension on the muscle is the tension on the muscle. So what I'd say to people is I think most people probably change up things too much because there is like a neurological adaptation to doing a specific exercise where you get stronger at it. And so now you're using more load.
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Dr. Layne Norton: Tools for Nutrition & Fitness
You can create more mechanical tension. But if you're always changing things up, you might not take advantage of that full, you know, kind of neurological adaptation. But. If you're always doing the same exercises, it's too easy to get comfortable and fall into, well, did I do three sets of 10 and I always do three sets of 10 and I use this weight and that's what I do.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And now you're no longer progressively overloading. So I think there has to be a balance between enough changing of exercises to kind of promote some novelty, because as you know, novelty, there's a reward center in the brain for that, just changing something. And think about any time you're going to try a new workout, you get a little excited about it.
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Dr. Layne Norton: Tools for Nutrition & Fitness
When I was going to try Zach's way of training three years ago, I was like, oh, I was very, very excited about it. So I think there is a place for that. But I think people tend to fall into a little bit too much of doing the same thing over and over or constantly changing things because they're always chasing that novelty. And I think that the reality is probably somewhere in the middle.
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Dr. Layne Norton: Tools for Nutrition & Fitness
But specifically for older – over 50 – I think whatever you can do with low pain level and be consistent with that you enjoy, that's what's best for you. I mean I always tell this story. I had a client who – they loved CrossFit. They loved doing CrossFit. And they said, but I want to build muscle and I know it's not the best workout for building muscle.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I said, it might be for you because if you hate bodybuilding training and you're not motivated to go do it and you don't enjoy it, you're probably not going to work hard at it. And so maybe for you, a CrossFit workout is the best muscle building workout because if I try to get you to do something else, you'd hate it and would lose motivation.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Exactly. So when we look at like – I think this might be interesting for some of your listeners. So when we look at how much muscle you can build after a certain age – you can build the same amount of muscle as a percentage of your starting skeletal muscle mass, okay? So what I mean by that is once you're 50, 60, you've usually lost some muscle, okay?
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Dr. Layne Norton: Tools for Nutrition & Fitness
And if you've never lifted before, if you go into lift, as a percentage basis, It appears that you will still gain the same amount of lean mass. But, for example, if somebody has 80 kilos of starting lean mass, most of your podcast listeners are USA, I assume.
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Dr. Layne Norton: Tools for Nutrition & Fitness
So let's say somebody has 150 pounds of lean mass when they start, just throwing out a random number, and they gain 10% over a couple of years. Now they have 165 pounds of lean mass now. They've gained 15 pounds, but the percentage is 10. If somebody starts and they have 120 pounds of lean mass, 10% of that is 12 pounds.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
They gained an absolute less amount, but as a percentage, it was similar or same. And we actually see that with women too. Women actually develop as a percentage of their starting lean mass. the same percentage increase in lean mass as men when they do the same level of hard training. So what I tell people who are, I'll hear people say, well, you know, I'm too old to start resisting. No, no.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Now is the perfect time to start right now. And honestly, it doesn't take a huge dose. I mean, if you want to be like, you know, go get into powerlifting and like compete at competition. Yeah. Now it takes a bigger dose. Right. But
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Dr. Layne Norton: Tools for Nutrition & Fitness
What it takes to get, and I'm just going to throw a number out, 80%, the majority of the benefits for health, strength, resistance training, you could probably get in three, four sessions of 30 to 40 minutes. You don't have to have a huge input of time. And just look at the depression study we talked about. Obviously, that's not like muscle and strength, but two sessions of 25 minutes.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And just because something has a biochemical pathway doesn't mean it will create an outcome. But if there's an outcome, there's absolutely a mechanism to explain it. Now, let me give you an example of why this stuff can be so complicated and why it's so easy for people to, if you want to create a narrative, you can always find a study to create a narrative.
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Dr. Layne Norton: Tools for Nutrition & Fitness
I mean, it is an absurdly low dose that you require. And I think... A lot of people – I try to be careful about this too – will see how I train, which is two, three hours a day for five days a week and think that's what's needed. No, no, that's what – I want to go win a world championship. That's what's needed for that. It's not needed for you to build muscle and get stronger.
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Dr. Layne Norton: Tools for Nutrition & Fitness
And even when I was at grad school across the street, they did a study in frail elderly where they had them – basically they had trouble like standing up from a seated position. And by the end of a 12-week study of them like progressively overloading them, which was basically like them just lowering the seat at first, right? And then maybe adding like a little bit of weight.
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Dr. Layne Norton: Tools for Nutrition & Fitness
They saw these people built muscle, built bone, got healthier, better quality of life. And these are people in their 70s. And there was a study in Australia that actually got on the news. Peter Attia talked about it with elderly women who I think they were above age 70. And there's some of them in there deadlifting like 150, like upper hundreds in deadlift, you know. It's incredible, man.
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Dr. Layne Norton: Tools for Nutrition & Fitness
how I took a class called skeletal muscle structure, function, and plasticity. Your skeletal muscle is so adaptable. It is such an adaptable tissue. It's amazing. The same thing that can allow somebody to squat, Jesus Oliveira, shout out, squat over a thousand pounds is the same tissue that can allow somebody to run a hundred miles like David Goggins. Think about that. That's
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Dr. Layne Norton: Tools for Nutrition & Fitness
really incredibly adaptive. And so what I'll tell the people, regardless of your age, your sex, whatever demographic you are in, resistance training for just a couple times a week for a short period of time will drastically improve the prospects of your quality of life, your longevity. I mean, if we look at hand grip strength, we look at lean mass, they're all
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
inversely associated with mortality, especially the older you get becomes a stronger association. And I always tell people, I'm like, it's not about the hand grip strength. This is a proxy for just strength overall, right? There was a study where they looked at pushups and found pushups were inversely associated with mortality. It's not that doing push-ups is magic.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It's that that is a proxy for that person being strong. And we focus so much of our attention, especially like on falls in the elderly, right? Well, if they had more bone mass, they wouldn't break their bones. What if they didn't fall in the first place because they were strong enough and had good enough gait and balance to catch themselves?
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Dr. Layne Norton: Tools for Nutrition & Fitness
And oh, by the way, nothing better for increasing bone mass than resistance training, right? So I am a huge fan. And then we already talked about like the metabolic, like skeletal muscle. Gabrielle touched on it. It was one of the first things Don Lehman said when I came in his lab. He goes, skeletal muscle fits every definition of an organ. And we don't talk about it like an organ.
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Dr. Layne Norton: Tools for Nutrition & Fitness
We talk about like it's this inner tissue that just sits there. And it is not. It sends out signals to other tissues. It integrates signals from other tissues. It is an endocrine organ. And so many people have unhealthy skeletal muscle. And if we treat and what happens when you resistance train, what happens when you build muscle? Muscle is a metabolic sink. It is greedy, right? It's sucking up.
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Dr. Layne Norton: Tools for Nutrition & Fitness
It's incredible. You could take people who are type two diabetic. And if you get them on a slight calorie deficit, you get them to start exercising. It is incredible how fast their blood markers will start to resolve. Like they can still be obese and you'll see their blood markers start to resolve within – like you'll see improvements in weeks.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Aspirin, we would agree, is an anticoagulant. There's a reason they give it to patients who are at risk for heart disease or a heart attack. It's because it reduces blood clots, reduces coagulation. It also activates procoagulant pathways. But the overall outcome is anticoagulation.
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Dr. Layne Norton: Tools for Nutrition & Fitness
Lehman did a – I want to say a 16-week study in either diabetic or pre-diabetic women back in like 2003 I want to say. And he said within four weeks, he said, we already saw these blood markers start to resolve.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Like your HbA1c hasn't resolved, but a lot of these other markers started to resolve because at a fundamental level, at least in my opinion, and other metabolism people may disagree, I'm a big fan of Occam's razor, which is plainly stated, all things being equal, the simplest explanation is typically true. The actual...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Hardcore scientific definition is the hypothesis that requires the least amount of assumptions is usually true. You're putting in so much energy into a system and you're running out of places to put it. So you have skeletal muscle mass, you have liver, these other tissues in the periphery, and then you have adipose tissue.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And did you know they actually show people who have more adipocytes are actually more resistant to type 2 diabetes? So they have more smaller fat cells that can soak up more of this stuff. And since type 2 diabetes is basically too much glucose in the blood, right? and a lack of insulin sensitivity, small adipocytes are more insulin sensitive.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so what happens is we, at least in adipocyte physiology, We used to think of adipose as also an inert tissue, and now we know that's not true either. And lots of different cell types.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But most fat cells, at least based on the literature I've read, and again, I'm happy to have somebody correct me who's an expert in this, but they can expand to a certain point where it really becomes difficult for them to get bigger.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
The integrity of the cell, because you've still got a cell wall, plasma membrane and everything, and you have an extracellular matrix that is scaffolding this fat tissue onto your body. And so at a certain size of adipocyte, it basically becomes, you just can't pack any more in there, okay?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so if you can't put any more in muscle because muscle isn't, you're not active and muscle's not moving and churning through substrate, And you can't pack anymore into adipose. Where does it wind up? It's in your blood. And now when your blood levels – it's interesting because there are some people who have all these theories.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But if I wanted to create a narrative that aspirin was bad for blood clots, I could say, well, look at these biochemical pathways it activates. And you see this, like, for example, I could create a narrative that smoking is not bad for you, okay? I remember reading a meta-analysis of the effect of smoking on the risk of adenocarcinoma, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But like one person, a researcher was like, well, I think branched chain amino acids actually cause insulin resistance because we see them elevated in the blood in type 2 diabetes. And I was actually in a – I was a grad student watching this person present and I put my hand up. I said, isn't everything elevated in the blood and type two diabetes?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You know, why are we, why are we picking on branched amino acids? So you do have some people who are, who can become type two diabetic, who aren't obese. They tend to have not as many fat cells, which sounds like it'd be an advantage. And if you're lean or sorry, if you are not overeating and and getting enough exercise in, it probably is an advantage because you have less overall fat mass.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But you are going to reach that critical mass of an adipocyte of about 100 microns, I think it is, faster. because your overall fat cell number. So at the same fat mass, your fat cells are bigger and bigger fat cells are less insulin sensitive. In fact, one of the treatments for type 2 diabetes, sulfonylureas, I think they're called, they're PPAR gamma agonists.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
They actually increase the production of fat cells. They create new small fat cells. Now you have a place to put stuff and you lower your blood glucose. So very- It's a reservoir. Exactly. And I'm overgeneralizing to be sure. And again, I hope if I've butchered anything, somebody will come in and correct me. They will.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But what's amazing is this stuff in the blood, you just got to get stuff moving. Like because you start doing exercise, start controlling your calories a little bit. Guess what? You're oxidizing things to the Krebs cycle. You're going through glycolysis. You can now start to pull things in. Right. You're using this substrate. You start to pull things in.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And because you're pulling things in now, adipose can start to release some of its free fatty acids into the bloodstream, which can also facilitate this. So using muscle, you are it is a partitioning effect. And it doesn't take long to start lowering this glucose, blood lipids, these things in the blood.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It can actually resolve, you know, at least those markers can start resolving themselves pretty quickly, which is why, you know, when we look at weight loss, what level of weight loss they say is clinically relevant, it's only 5%, right? Which you'll have obese people and they'll say, well, 5% weight loss, you see these big benefits in like blood lipids and metabolic health, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You wouldn't think with just 5% weight loss you would get that, but you do because you're just giving a little bit of space to get that stuff in the blood out. Now, again, this is my – I want to be very clear. This is not a proven thing. I feel pretty strongly that this explains a lot. But again, this is my personal opinion about how these diseases develop and whatnot.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But it is, I think it's relatively simple.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And there's a forest plot with probably about 50 studies. And most of those studies are to the very far right of the line, which is increases risk. And I think the overall effect was like 300% or 400% increased risk of adenocarcinoma. But there were two studies that were to the left of the line, not by much, and it wasn't statistically significant.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Well, in practice, you fall farther going downstairs than you do going up.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And it's psychologically and emotionally fatiguing as well.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, you're starting to work from Herman Ponser and really great lab looking at energy expenditure that he does a lot of great stuff. And so that study was looking at several thousand people, I think, looking at their total daily energy expenditure and really found it's pretty flat from like age 20 to age 70. And then it kind of starts to go down. But you can tie it to the loss of lean mass.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And same thing for basal metabolic rate when they do indirect climatry. If you look at – and this goes for – so older people, also women versus men, and then also – Type 2 diabetics versus non-type 2 diabetics, obese versus non-obese. I think the number is like over 80% of the variance in BMR is completely explained by the lean mass, by the amount of lean mass somebody has.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But I could say, hey, look, I could cite these two studies, PMID. You know, they showed no increased risk of adenocarcinoma and actually might be slightly protective. And by the way, did you know that smoking decreases the risk of Parkinson's by 30 to 40 percent? And by the way, that's very consistent in literature.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And by the way, the last 20% probably is explained by where that lean mass occurs because liver, for example, is a more metabolically active tissue gram per gram than pretty much any other tissue. Skeletal muscle is more metabolically active than fat tissue. But for a lean tissue, it's actually somewhat metabolically slow because its turnover rate is only like 1% to 2% per day.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, right, right. But on an absolute amount of calories you burn, you burn a lot in muscle because you have so much of it. Great point. So things like gut, liver tissues, per gram of tissue are very active. So...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, it just doesn't seem to be – for a long time, we spent so much time focused on the metabolism side of things when we're looking at aging, when we're looking at obesity, and we just didn't really find impressive stuff. So obese people don't have slower metabolisms on average. The research shows that actually on an absolute basis, they're faster than people who are normal weight.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
When you standardize for lean mass, it ends up being about the same. People who are type 2 diabetic, same thing. When you standardize for lean mass, if anything, they have a little bit faster BMR. And so if you think about it, it actually kind of makes a little bit of sense on a biochemical level because if you're insulin resistant, you're also insulin resistant in fat tissue, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So like, okay. So it makes sense that maybe you like waste some more energy because you're not able to put it where you want to put it, right? So The people get upset about this because it's got to be metabolism, metabolism. And then GLP-1 memetics have really kind of shown, no, the answer to this question is very much on the appetite side of things.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It's like we tried to make a bunch of different drugs that would increase metabolism. We tried to do all these things to increase metabolism and nothing seemed to really make a big difference. And then we came out with the most powerful appetite suppressants in the history of mankind and people are losing large amounts of weight and keeping it off.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I think people got too focused on that metabolism side or what I hear a lot of is from like post-menopausal women. I'll hear somebody say, my metabolism dropped. What probably happened is You're sleeping less. You're more stressed. You don't feel as good because the hormonal changes. You don't feel as good.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so you spontaneously became less physically active and didn't realize it because our NEAT, like our non-exercise activity thermogenesis, our non-purposeful physical activity that we do, fidgeting, pacing, is actually a large portion of our daily energy expenditure. And people get this wrong. You can't make yourself do more NEAT because then it's just exercise.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I can start creating this narrative that smoking, but we know smoking is not good for you. It's not good for you. It raises the risk of lung cancer, all different kinds of cancers, cardiovascular disease, massive increase in risk, right? But I could thread the needle of science using these cherry-picked studies. And so what I'll tell people is if I go into a topic, if I go into something,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If you're purposely doing it, it's exercise. It's all subconscious, right? But if you're not sleeping as well and you're feeling worse, spontaneously, you'll just not move as much. And I know that people like that feels like there's like a lot of judgment, shame associated with that. But it is the truth. It is a practical limitation and it may not be metabolism.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I guess I'm a little bit pedantic with that, but it still contributes to your overall energy expenditure. And so, again, they've looked at this and I mean, there is some evidence that like if your estrogen drops and you replace that with supplemental estrogen, that that can like help out with like maybe 50 to 100 calorie energy expenditure per day.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So if you're replacing something that's like now clinically low.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And that's where it's hard to disconnect that, right? So yeah, I think metabolism wise, the results ended up being pretty underwhelming for all this stuff that we just assumed, well, if somebody's overweight, it's because they're slow metabolism. The research didn't pan that out, but I still think it was very interesting.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And again, it speaks to like the power of the mind and the connection in the mind of how some of these drugs act. But I do tell people when they say, well, you know, I, you know, calorie deficit didn't work for me. And I, I, I, you know, obviously my metabolism was messed up because, you know, I had to get on Ozempic to lose weight. I'm like, well, it doesn't really do anything to metabolism.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Like the speed of your metabolism is, What happened is you just you no longer mindlessly snack. You feel you are now in touch with your satiety signals. And that's why you're losing weight. And that's why these drugs, they work.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I think my take is pretty balanced on this, which is I think they appear to be great tools for people reducing their intake and reducing body fat and it functions through appetite. I mean these drugs are GLP-1 memetics and so GLP-1 is a hormone secreted by the gut in response to feeding and it acts on the gut as well as the brain to reduce appetite, slow motility.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So it's a satiety hormone essentially. Now, it has a very short half-life in the body. So the reason – a lot of people will come out and say, well, there's things you can do naturally to increase your GLP-1. This is like talking about – I mean, yes, a BB gun fires a projectile and a tank fires a projectile. But there's a pretty big difference, right?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So with GLP-1 memetics, what's happening is they're taking – that protein and changing out some of the amino acids in that protein. And it basically just gives a much longer half-life. That's why people can take it, you know, once a week or whatever it is, because it just stays around much longer.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so if you think about the food environment we live in, which is free access to cheap, hyper palatable foods, our brains for the most part are probably not equipped to regulate appetite in that environment. And it really actually is kind of incredible how resilient the human body is, because if you look at when the obesity crisis started, we already had ultra processed foods available.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
We had cakes, cookies, all these sorts of things. But the difference was. You had to go to the bakery and get it. There had to be some small barrier, right? And then I think kind of the barrier that got flipped was basically now in the last 30 years, you can go anywhere and get access to cheap, ultra-processed, hyper-palatable, calorically dense foods.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
What I'm looking for, highest quality of evidence, is first off, do we have some meta-analyses on this topic?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And they just don't have the same effect on satiety that normal food does. Like a Kevin Hall study at NIH where they took people from a minimally processed diet and switched them to an ultra processed diet. And they spontaneously increased their caloric intake by 500 calories a day, like overnight. That may sound like not a big deal to some people listening. That is a very big deal.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah, I mean, assuming that there's no increase in energy expenditure, which we know happens over time. But with these GLP-1 memetics, they're slowing down mobility. They're acting on the hypothalamus. They're reducing appetite. And it's a very powerful effect. Now, some of the side effects are like nausea. Some people reported kind of like a not freezing, but like too slow motility, essentially.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So there's some GI side effects, which are kind of to be expected with something like this. And. And, you know, on one side, you've got it's so funny how everything gets politicized these days. But on one side, you've got people saying, oh, these drugs have no side effects whatsoever.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And, you know, I think everybody should be on GOP ones because they were not made to live in this food environment. And then on the other side, you've got people saying. Well, this just obliterates the need for hard work and these people don't take accountability. And I don't really think either of those messages are really useful. I think there's a lot of nuance here.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I mean it's a drug and every drug is going to have side effects, some worse than others for different people. And so for some people, it's not going to make sense to take it based on their lifestyle and side effects they get. But for other people – I did a post on this where I talked about how – much weight people lose on average.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so many people in the comments said, you know, I've lost a hundred pounds or I've lost 80 pounds or whatever it is.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah. One of these GLP one memetics. And again, going back to our conversation of big rocks, people worry about lean mass loss. They worry about, there was a study in, I think rodents where they saw an increase in thyroid. I want to say thyroid cancer or something like that, but it was not really a physiological dose. And again, it's, it's rodents.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Absolutely. So a meta-analysis is basically we are trying to compile studies that ask similar questions and look at what is the overall effect? Do we have a consensus in the literature? And usually they're going to show some kind of forest plot of all these studies. And however far right or left of the center line is kind of giving you an idea of how powerful the effect was in that study.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
People say, well, we don't know what the long-term effects of these drugs are. Well, they've actually been around for diabetes treatment for a couple of decades now. But, I mean, do we know what they do in 50 years? I guess not, but we know what obesity does. So I'm going to take Ron White's line, which is shoot the alligator closest to the boat.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I think if somebody is very overweight or obese and they've tried a bunch of different methods and they just – people say, well, they just haven't been consistent. OK, so we can live in fantasy land or we can live in the real world, which is maybe some people just need some more training wheels than other people.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
OK, if we could stop putting like an ethical judgment on how easy or hard it is for certain people to do certain things. I mean, it's easy for me to say just be consistent because nutrition has never been a problem for me. I've never struggled with my weight, but I struggled in other areas of my life that why can't I just be more consistent? Why can't I just do the things I know I need to do?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I'm sure you would feel the same way about certain things in your life where it's like, well, I know logically what to do, but it's hard for me to do it, right? And so if we look at the burden on the healthcare system of obesity and these type 2 diabetes and then all the metabolic diseases associated with them,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It's hard for me to imagine a scenario where this is not a big net positive, to be quite frank. Now, I want to, this is, as my friend John Deloney says, it's both and, okay? Some people, this is really going to help them and it should be done in concert with lifestyle changes and lifestyle education.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Because we don't want people to go from eating a lot of a crappy diet to a little of a crappy diet, right? We want them to make better choices overall. But sometimes, again, habit coupling, people don't get motivated and then get results. People start getting results and then get motivated, right? And so a lot of times people will start losing weight and now they're motivated to go to the gym.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
They're motivated to eat better. It doesn't happen in a linear path. These things are kind of like you know, like the opposite of a vicious cycle where this is, you're getting into a good cycle, right? And a lot of people tend to fall into these categories where when things go bad, they go really bad because it's a vicious cycle. When things go well, they go really well because it's a good cycle.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so what I would say is with the concerns about GLP-1s, the one I hear most is loss of lean mass. So in studies, people who use GLP-1 medics, they lose like 30% to 40% of the weight from lean mass, which is a concern. But by the way, that is similar to the amount of weight from lean mass people use who diet without resistance training or exercise.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I don't think that it's a unique problem to GLP-1s. And my guess is – When we start getting studies that combine exercise with GLP-1s and look at lean mass retention, we'll probably see pretty similar results. So I'm not super worried about that.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
On a practical level, I can see some concern with it because if you don't have much appetite, you're usually not selecting protein as kind of your first line of what you're going to pick. And additionally, fiber, you're not usually going to select as your first. So I think, again...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
These are great kind of like if we think about like training wheels, I think these are great training wheels for people. And through natural just having less appetite, people start controlling their intake better and then all these other habits start to fall into place for some people.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I talked to a friend who, she's a nurse practitioner, and she tried a GLP-1 memetic just because she's like, I'm a nurse. I want to see what this stuff is like for me. And then she talked to a lot of her clients. And the anecdotal feedback that popped up a lot was it stopped the food noise in my head. I wasn't thinking about food all the time. I just... Stop thinking about it so much.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And then you can see the confidence intervals in terms of how much variability there was. And then you can see the thickness of the dot on there, which shows how much it contributed to the overall study. analysis by usually how many subjects were in it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And if you look at obesity, I mean, again, it really is on the appetite side. We know that obese people have lower sensitivity to satiety signals. They get a greater reward from food. Like I just posted about a study the other day where they gave a milkshake to people. And they didn't really see a dopamine response.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But in people with binge eating disorder, when they give something like that, they do see a dopamine response. So a lot of it is contextual, right? And so I think a lot of it is contextual around obesity of, okay, these are people who get a greater reward from food on average. They're thinking about food more often. They've probably also –
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
dealt with people telling them in their entire life or however long that they need to lose weight. And so food is always on their mind in one thing or another. It's kind of like in Ghostbusters where they say, you know, don't think about anything bad. What's the first thing you're gonna do? You're gonna think about something bad, right? And so,
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Trying to calm down food noise while knowing that you need to eat less food is probably pretty difficult. So on the whole, I think these drugs are positives. I think it's going to lower the health care burden. And I think it's going to help a lot of people. And the other thing I'll say is like there's been a lot of pushback in the fitness industry by fitness influencers. Why do you think that is?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
If I think back about when I might have had that sort of reaction, I was in my early 20s, and that's when I thought obesity was a choice. I still think there is personal responsibility involved in obesity. But I think my feelings about obesity at that time were, if somebody's obese, they're making the choice. They don't care about the stuff they eat that...
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
mindfully they are choosing to eat these foods knowing this is going to be the outcome. Like self-inflicted. Yeah. And I don't think that's the case at all. I think a lot of people's habits and behaviors are on autopilot. I can remember very clearly, I dropped my kids off at school one day. I stopped at 7-Eleven to fill up with gas and grab something from the store, a drink.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Exactly. And so you're trying to... Now, you can do a bad meta-analysis based on inclusion criteria, you know, and that's where it's important to look at. But let me give you an example of a meta-analysis I cite pretty frequently. The inclusion criteria is very important to make sure that you answer the question that you want to answer. And I say this when you're reading scientific studies.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And there was an obese woman in front of me and she was getting two slices of pizza at 8 a.m. And at first, I kind of had that knee-jerk response of, oh, she's so lazy. Of course you're over. And then I thought, you know what? This is probably something she's done for a long time. This is probably a very habit where she goes to 7-Eleven, she gets pizza.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Or on Tuesday morning at 8 a.m., she's around this area and she goes to 7-Eleven and gets pizza. And maybe not. But I think a lot of people out there are like that where their habits and behaviors are very much on autopilot. It's not this mindfulness that we think they're doing. And that translates into other areas.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And the other thing I realized is I'm like, it can't be laziness, like all of it, because there's obese people who are very successful in other areas of their life. So they don't want to work hard. And so... At least not for everybody. That can't be the explanation. And I think with fitness influencers or people who have, you know, actually they've worked hard, they've built a good physique.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It's almost like how dare you get results without doing it yourself. I did this without any help, you know. And the reality is you might have had help because your upbringing might have not been food focused. You might not have had a mother who was always on you about food. Or you might not have had parents who shamed you if you didn't clean your plate.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
You might have had genetics that made you more sensitive to satiety signals. You might have had a phenotype where if you overeat, you tend to just become spontaneously more active. That's part of the obese resistant phenotype. And so you might have had an advantage and you just didn't realize it.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
So I think if we could just get away from the judgment of stuff and look at – take the judgment, all that stuff out of it. Does this seem to help people and is it going to be a net positive on society? Thomas Sowell said in order to make compassionate policy, you have to have dispassionate analysis of the data. And the data says this is going to be massive for our society.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And it's, it's a huge benefit. So regardless of my personal feelings of, Hey, somebody should be able to look, look at Ethan Suplee lost 300 pounds doing it through all hard work and exercise. I'm pretty sure I've talked to Ethan about this and he said, I think this is great, you know, because it's hard to get people to believe if people believe what they can see.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And so if they start seeing results, then they can buy in and. Yeah, I think overall it's a net positive. So, I mean, maybe studies will come out in 10 years and people are falling over dead from this stuff and we'll say, oh, whoopsies. But, I mean, you have to shoot the alligator closest to the boat.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And right now the biggest burden on our health care system, I think I'm correct in saying this, and the biggest threat in a lot of ways is how metabolically unhealthy our society is getting.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
I'm like, listen... Just because there's a headline in even a paper, just because the conclusion says something, that is the author's opinion. You need to check to see, did they actually test what they're talking about? And are the tests they use valid? So this meta-analysis was looking at lower carb diets versus higher carb diets or low fat diets.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Yeah. I mean, if you had something that like, if we came out with a drug and it's like, it looks like for a lot of people, this can fix opioid addiction, right? You'd give them that drug. We'd be shouting from the rooftops and celebrating, right? We wouldn't say, well, you just got to gut it out and work harder. You know, you just got to, you just got to want it more.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It's like, no, like there's some, there's, yeah, there is some personal responsibility there, but, And there are choices and things that can be made, but why are we trying to make this barrier so high for people? Like let's lower this barrier.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Okay, so... This is where it's very important to give the appropriate context and nuance. I'm glad you set it up the way you did. So I always tell people when it comes to almost anything, have guidelines, not hard rules, because hard rules will get you to do things that are kind of dumb, right? So for example, if you say, I'm never going to eat processed foods.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Well, whey protein is processed, but if you look at the data on whey protein, it improves metabolic health. It increases lean mass, body composition, even lowers inflammation. So, I mean, if we're just going to say all processed foods are bad, well, isn't then way bad? So guidelines in that nature.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Same thing for sugar because obviously, okay, well, added sugar, it doesn't have a big satiety benefit. It's calorically dense, makes food very palatable. I'm going to come back to that because it's contextual. But fruit has sugar, and biochemically, not really that different. I mean, if you're talking about sucrose, okay, it's a molecule of glucose and fructose.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And the inclusion criteria, this was done by Kevin Hall of the NIH back in 2017, I want to say. And I thought he did a great job at the inclusion criteria, which was we're only going to include controlled feeding trials where the food is provided to participants because obviously we know the limitations of, you know, free living studies with nutrition.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Okay, a lot of fruits have glucose and fructose in them, right? So if sugar has some inherent lipogenic biochemical – toxicity, addictive quality, whatever, we should see similar effects across different sources of sugar. And we don't see that, right? And even when it comes to some of the processed foods, people don't realize what goes into making something hyperpalatable is complex.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
It's not just sugar. It's not just fat. It's not just sodium. It's texture, mouthfeel. You mentioned temperature. All these things matter. And in fact, there was actually a study a while back that suggested that texture might actually make a bigger impact on the palatability of a food than even the sugar content. And let's take it more from a mechanistic level.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
From your example, if you're in the confines of your calories, what happens? I would say a high sugar diet is still not ideal because it's going to be hard to get enough fiber in a high sugar diet. But a long time ago, beginning of grad school, I was under the opinion that sugar and high fructose corn syrup were calorie per calorie, more fattening, metabolically unhealthy.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And I was at a graduate mixer with a professor named Manny Nakamura who was at Illinois. And he had done some of the feeding studies in rats with fructose and seen these weird metabolic effects, right? And I overheard him having a conversation with another professor and I was shocked by what he said because he's the one that did some of this research.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
And the other professor said, so high fructose corn syrup is bad and fructose is bad. He goes – No, it's really just the calories that are in it. It's easy to overconsume. People consume it through soda and they just eat too much. And the guy was like, well, you showed all these things in these mice. He goes, we fed them like over 50% of their calories were from pure fructose.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
That's pretty much impossible to get through the diet unless like you're literally doing nothing but drinking soda. And he said, you know, we showed a pathway, but that's not practical in terms of Like the application to humans. And so I got curious. I really started going down the literature on sugar trying to say, OK, is he OK? Is he right about this?
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Is it is it really not, you know, calorie per calorie more damaging than than non sugar carbohydrate? When you look at sugar intake, it is associated with increased levels of inflammation. It's associated with obesity. But there are what we call confounding variables, which is people who eat a lot of sugar tend to eat a lot of calories. So if we look at
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
Here's my favorite, human randomized control trials where we control total calorie intake and sugar intake. What do we see? And probably the best example of this was a study from Surwit back in, I want to say, 1997. And the reason I'm going to pick out this study is because it had the best controls in it. So they provided all the food to participants.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
The protein, carbohydrates, and fats were all the same. It was a – I think it was a 1,200-calorie diet. And they provided all these meals for six weeks and looked at fat loss and some blood lipids and those sorts of things. And they found that – so one group was getting over 100 grams of sugar a day. I think it was around – I mean it was based on some like body weight, energy expenditure stuff.
Huberman Lab
Dr. Layne Norton: Tools for Nutrition & Fitness
But I think it was around like – 110 grams of sucrose per day, right? A lot of sugar. Other group, like around 10. So 10 times different sugar. And at the end of the study, there was no difference in fat loss. There was no difference in lean mass retention. There was no difference in almost any marker they looked at. The only difference they saw, all the blood markers improved.