Andrew Huberman interviews Dr Layne Norton on the science of nutrition, fat loss, and muscle building
Andrew Huberman speaks with Dr Layne Norton, a PhD scientist and nutrition researcher, about the fundamentals of eating for health, fat loss, and lean muscle.
Summary
Andrew Huberman hosts Dr. Layne Norton for a wide-ranging conversation on the science of nutrition and body composition. Norton explains that "calories in, calories out" is far more complex than it sounds, with food label errors, individual differences in gut microbiome, and highly variable energy expenditure components — particularly non-exercise activity thermogenesis (NEAT) — all playing significant roles. He argues that protein is the single most important dietary lever for body composition, noting that benefits begin to plateau around 1.6 grams per kilogram of body weight (with some evidence for marginal gains up to 2.4–2.8 g/kg), and explains why plant-based protein sources require more careful planning due to lower leucine content and co-packaged calories. Norton also addresses minimally processed versus ultra-processed foods — citing Kevin Hall's research showing people spontaneously consumed 500 extra calories per day when switched to ultra-processed foods — as well as artificial sweeteners, seed oils, and creatine monohydrate, consistently deferring to human randomized controlled trials over mechanistic arguments or epidemiology alone.
Key Takeaways
FULL TRANSCRIPT
What Calories Actually Are — and Why "Calories In, Calories Out" Is More Complex Than It Sounds
Andrew Huberman: Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I'm Andrew Huberman and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. And now for my discussion with Dr Layne Norton. Dr. Norton, thank you so much for being here. This is a long time coming and I have to say, as a fellow PhD scientist, I feel a great kinship with you. I know you have tremendous experience in fitness and nutrition in a number of areas. I'd like to start with something that's rather basic and yet can be pretty complex, and that's this issue of energy balance and energy utilization. What happens when we eat food of any kind and how is that actually converted into energy — as a way of framing up the discussion around weight loss, weight maintenance, weight gain, and body composition?
Dr Layne Norton: It's a great question, and like you said, this is one of those things where people use the term "calories in, calories out" and they say, "Well, that's way too simplistic." And I'm like, if you look at what actually makes up calories in, calories out, it's actually very complicated. So a calorie just refers to a unit of energy — of heat, specifically. Really what you're talking about is the potential chemical energy that is in the bonds of the macronutrients of food. And by digesting, assimilating, and metabolizing those nutrients, we are able to create energy. The end product of that, mostly, is ATP — adenosine triphosphate — which is your body's energy currency. So a lot of metabolism is simply creating ATP.
Protein is a little bit different because protein gets converted to amino acids, which can be used for muscle protein synthesis or protein synthesis in other tissues. But it also can be converted through gluconeogenesis to glucose, and there also are some ketogenic amino acids as well. Then you have fatty acids, which are able to create energy through what's called beta oxidation, where essentially you're taking these fatty acids and lopping them off two carbons at a time to produce acetyl-CoA, which again can go into the Krebs cycle, produce those hydrogen ions that can then power the production of ATP. So that's kind of at the cellular level of how this stuff works.
But stepping back and taking it back out — what does that have to do with weight loss or weight gain? When you think about the balance of energy in versus energy out, it sounds very simple. But let's look at what actually makes up energy in versus energy out. First of all, you've got to realize that the energy-in side of the equation is more difficult to track than people think. One, food labels — which we like to think come from on high — can have up to a 20% error in them.
Huberman: Really?
Norton: Oh, yeah. The second aspect is there's what's called metabolizable energy. So if you have food with a lot of insoluble fiber, typically insoluble fiber is not really digestible. So you could have quite a bit of carbohydrate, but if you can't extract the energy from it — and typically this is because insoluble fiber from plant material means the carbohydrate and even some of the protein is bound up in the plant structure, which makes it inaccessible to digestive enzymes — this is what adds bulk to your stool and whatnot, but again reduces the metabolizable energy. And there's some evidence that based on people's individual gut microbiome, some people may actually be better at extracting energy out of fiber compared to other people. So just starting off right there, there's quite a bit of play in the energy-in side of things.
Now, one of the things people will say is, "Well, see, that's why you shouldn't worry about tracking calories, because if the food labels can be 20% off..." And what I'll say is, okay, I understand where you're coming from, but typically if it's off, it's going to be consistently off. And if you're consistent with how you track it, eventually you'll be able to know kind of what you're taking in.
Breaking Down Energy Expenditure — BMR, TEF, Exercise, and NEAT
Norton: So now let's look at the energy-out side of the equation, which is actually way more complicated. Your energy out is a few different buckets. The first one, and the biggest one, is your resting metabolic rate. Your RMR — for most people — is anywhere from 50 to 70% of your total daily energy expenditure. Sedentary people will be on the higher end of that, so it'll be a bigger proportion, whereas people who are more active it'll be a little bit lower. Not because their metabolic rate is lower, but because they're expending a greater percentage of their calories from physical activity.
Then you have something called the thermic effect of food, which is a relatively small percentage of your total daily energy expenditure — about 5 to 10%. Very difficult to measure, and usually what researchers do when they're looking at this stuff is they just make an assumption about it and use a constant. That refers to the amount of energy it takes to extract the energy out of food. You can't just eat food and have it just appear in your cells. It has to be systematically broken down and put into forms that can actually produce energy.
A lot of times people will say something like, "Not all calories are created equal." That's not true, because a calorie is just a unit of measurement. That would be like saying not all seconds on a clock are created equal. Yes, they are. All sources of calories, however, may have differential effects on energy expenditure and appetite. So if we look at something like fat, for example, the thermic effect of fat is about 0 to 3%. Meaning if you eat 100 calories from fat, your net will be about 97 to 100.
Huberman: So the process of breaking down that fat essentially subtracts some of the calories away because you used energy in creating ATP by breaking those chemical bonds?
Norton: Correct. Fat is actually the easiest thing to convert into energy. Then you have carbohydrate, which has a thermic effect of like 5 to 10%. So you eat 100 calories from carbohydrate — and obviously the fiber content makes a big difference on this — but you'll net 90 to 95. Protein is about a 20 to 30% thermic effect. So if you eat 100 calories from protein, you're only netting 70 to 80.
Now, people say, "Well, you can't eat too much protein." Can protein be stored as fat? The carbons from protein — it's unlikely they're going to wind up in adipose tissue, but if you're eating a lot of protein overall as part of a lot of calories, it has to be oxidized and it can provide a calorie cushion for other things to be stored as fat. But protein itself does provide a net positive for calories, just less so than carbohydrate or fat, and tends to be more satiating. So again, when people talk about whether all calories are created equal — yes, but all sources of calories may have differential effects on energy expenditure and appetite.
So that's the thermic effect of food bucket and the BMR bucket. Then we go to physical activity. Physical activity is essentially two parts. There's exercise, which is your purposeful movements — you go out for a walk, you do a training session, whatever purposeful activity. And then you have what's called NEAT, which is non-exercise activity thermogenesis. For example, when I'm talking and waving around my hands, tapping my feet — that's NEAT. The calorie burn from NEAT is actually pretty significant. We're not talking about 100 or 200 calories per day. We're talking about in some cases hundreds — maybe even close to a thousand — calories per day. And what's very interesting about NEAT is that it seems to be the most modifiable of BMR, TEF, and NEAT. NEAT seems to be far more modifiable.
Weighing Yourself Correctly — and Why Consistency Matters
Norton: The next thing is that a lot of people weigh themselves very sporadically. I'll tell people: if you're going to make intentional weight loss a goal, typically weigh in first thing in the morning right after you go to the bathroom, do it every day, and take the average of that for the week. Then compare that to the next week's average. As somebody who weighs themselves pretty regularly, my weight will fluctuate five or six pounds without seemingly changing much — and that's just short-term fluid changes. So if you're somebody who just randomly weighs in and you're eating at a calorie deficit, and you just happen to weigh in on a day where for whatever reason you're holding some more fluid, you go, "Oh, see, this isn't working." When in reality, your average might be dropping.
Weight fluctuations are actually identified as a major reason why people get discouraged from weight loss. It kind of stops the buy-in when they have a fluctuation up. So that's one of the reasons early on that low-carb diets tend to work really well — because people lose a lot of water weight really quickly and they get that buy-in. "Oh, this is working."
People think about doing a diet and losing weight, and they give no thought to what happens afterwards. Think about if you have some kind of chronic disease — if you're diabetic, you can't just take insulin once and that's it. You have to take it continuously, otherwise you're going to have problems. You can't create a new version of yourself while dragging your old habits and behaviors behind you. So what I'll tell people is — when someone says, "I'm doing a carnivore diet or this diet or that diet," I'll say, "That's fine. Do you see yourself doing that for the rest of your life?" And if the answer is no, you probably need to rethink what your approach is going to be.
Protein — The Most Important Lever for Body Composition
Huberman: Could you briefly talk about how macronutrients, including protein, impact satiety from the standpoint of somebody who would like to lose a few pounds, would probably be happy to gain a little bit of lean body mass in particular locations — directed hypertrophy, if you will — and how much they should focus on protein as a core component of creating this diet? And are animal sources of protein indeed more bioavailable — that's a tricky word — for sake of muscle building, but also for somebody who just would like to lose body fat, doesn't want to lose muscle, and would like to bring their weight down a few pounds?
Norton: Of the macronutrients, protein is definitely the biggest lever that you can pull. Even though it doesn't take a ton of protein to get a lot of the muscle-building benefits. I think the benefits really start to plateau out around 1.6 grams per kilogram of body weight. There's some evidence that maybe even up to 2.4 or 2.8 grams per kilogram may give a little bit more benefit. I think it probably looks something like an asymptote in terms of a curve — where as you put more into the system you always get a little bit more, but it just gets to the point where it's so infinitesimally small a benefit that for all intents and purposes there's no benefit. There doesn't seem to be really any downsides to it even up to very high levels of protein. José Antonio did a study that was a year-long randomized controlled trial, and they were looking at all sorts of different biomarkers. Basically, even up to four grams per kilogram of protein, they couldn't really find any negative health outcomes from it — other than people were just so satiated they ended up eating fewer calories.
So protein is a big lever because: one, it has a higher thermic effect of food, so you're getting a little bit more calorie burn per day — even though it's not a ton, because TEF is a pretty small percentage of your overall energy expenditure, but still a benefit. You're getting the effects on lean body mass. If you're in a caloric deficit, it's going to help preserve lean body mass. If you're at maintenance, it's going to help build or preserve lean body mass. And if you're in a surplus, it's going to help build or preserve lean body mass.
Huberman: If I'm going to eat, say, two grams per kilogram of body weight of protein, and I'm eating two or three meals per day, I'm certainly going to be eating more than the 30-gram threshold that was thrown around for a long time — the idea that we can only assimilate 30 grams of protein per meal. Should I just not worry about that? And should I worry about this 30-gram cutoff? Because I think balancing the 1.6 grams per kilogram body weight threshold with number of meals, with the need to exercise and work and live my life and sleep — pretty soon you run into bottlenecks where you just can't do it all, or you're spending so much time trying to focus on all of it—
Norton: You can't optimize all the things at the same time.
Huberman: You lose your mind and your body.
Norton: Most Americans get about 65 to 70% of their protein at dinner. Breakfast tends to be pretty minimal protein. So to answer your question, I do think that timing and frequency matter a little — not so much frequency, but distribution more so. But it's a much smaller lever than just getting enough total protein in.
Animal vs. Plant Protein — Bioavailability, Leucine, and Practical Solutions
Norton: As far as animal versus plant protein — I used to be in the camp of "there's no way somebody can build as much muscle on a plant-based diet." And now I think I've come back to: you can. It just requires a little bit more planning. And I don't want to say always, but it's very difficult to do without an isolated source of protein. So unless you're going to supplement with an isolated plant source of protein, it's very difficult to get enough without going over on total calories. Especially take somebody who may be calorically restricted trying to get enough protein from whole intact plant sources. You've got a few different things working against you. One, the sources of protein you're consuming also have carbohydrate and/or fat. Two, it's a less bioavailable form of protein. And three, it's a lower quality of protein in terms of — it typically has less leucine, fewer branched-chain amino acids, and fewer essential amino acids.
Huberman: You answered the question I almost interrupted you to ask, which was: does it boil down to the leucine content? And it sounds like that is one of the components, and that a lot of the vegan and vegetarian sources of excellent protein are co-packaged with calories from carbohydrates and/or fat that make it hard to stay under the caloric threshold — whereas a steak, or a piece of chicken, or an egg — well, an egg has a yolk which has fat, but is almost a pure protein-fat source with no carbohydrate along for the ride.
Norton: You can do it. It takes a little more planning, and if you're a vegan especially, you're almost always going to be better off supplementing with some isolated form of protein. Now, this is where people say, "Well, what about the limiting amino acids?" It's a consideration. Some of the better forms of vegan protein in terms of amino acid content are like soy. Now, I can hear everybody screaming online about their testosterone levels. In terms of actual outcomes and looking at testosterone, there was a recent meta-analysis looking at soy, and I think if it's your only source of protein then maybe the dosage is high enough to cause some unusual effects, but if you're just using it once or twice a day it doesn't seem to have an effect on testosterone or estrogen. So that can be a decent source of protein because it is a complete protein source. It does have a PDCAAS of one — which PDCAAS is basically a measure of protein quality based on whether it provides enough of all the amino acids so that none are limiting — and soy is one of the only vegan sources that achieves that.
Interestingly, potato protein isolate actually has a similar essential amino acid content to whey. It's just really hard to find. Another reason using an isolated protein can be helpful is because it's more bioavailable as well when it's been isolated out. When the protein is bound up in the actual plant material, it tends to be less bioavailable. Cooking can help increase the bioavailability because it breaks some of those bonds.
The other thing to consider with vegan sources of protein is the leucine content. One of the studies we did was looking at wheat, soy, egg, and whey — isonitrogenous, meaning we equated protein between the groups, isocaloric, we equated calories — and we looked at muscle protein synthesis. I think the meals were 15% of total energy from protein, so like a food guide pyramid level of protein. And we saw that in the wheat and soy groups, they did not increase muscle protein synthesis, but the egg and whey groups did increase muscle protein synthesis. Now what's really interesting is we went back and took wheat and added free leucine to it to match the leucine content of whey, and the protein synthetic response was identical.
Huberman: So leucine appears to really be driving this ship.
Norton: A few different options for the vegan folks out there. You can use an isolated source of protein — and there are going to be good options coming, because plant-based whey alternatives are going to be a great option for folks. You can add free leucine to whatever your source of protein is.
Huberman: Just buy supplemental leucine.
Norton: Now, it tastes horrible. It's completely non-polar. Does not dissolve in anything. Capsules — it can't really be put into capsules.
Huberman: Gross.
Norton: You could take a capsule. For example, if you're eating your normal meal, you could just take a capsule of like one gram of leucine. It's probably going to bump you up enough that you're going to be good to go. There are options like blends, especially with corn. Corn is actually very high in leucine as a percentage of its protein. Now, you've got to remember — you go eat corn on a cob and you're getting like two grams of total protein. So it's not that much leucine. But if you isolate out the protein and put it into a powder, now you're getting like 80 to 90% of the weight as protein. Corn is actually about 12% leucine in terms of the protein, so it's a great source of leucine. It is almost frankly deficient in some other amino acids, but you can blend it with a few other sources of protein — like soy and pea — and you can create these complementary blends that would actually have quite a bit of leucine but also some of the other essential amino acids. So there are options out there for plant-based folks. And we have seen people who are plant-based build impressive amounts of muscle. There are quite a few bodybuilders who are plant-based.
Minimally Processed Foods and Why Ultra-Processed Foods Drive Overeating
Huberman: Can we come up with a relatively short summary of the following — tell me if this is correct or not — that most of us should be focused on ingesting non-processed and minimally processed foods?
Norton: I would 100% agree that trying to focus on minimally processed foods is very important. The one caveat I would say is I think it's important to understand why processed food gets people to spontaneously eat more. Kevin Hall showed this in his study — and he designs some of the most elegant studies in nutrition. They basically took people from a minimally processed food diet and then gave them access to ultra-processed foods with very few instructions — just eat till you feel satisfied — and they spontaneously increased their calorie intake by 500 calories a day. That's massive.
Now, that being said, it depends on the individual and their goals. If your goal is to build muscle or maintain a high body weight for a sport — for example, like an NFL offensive lineman — your protein, your fiber, your micronutrients, these are your responsibilities. But those become much easier to hit when you have higher calories. If you're eating 4,000 calories a day for whatever goal you have, you're probably going to have some left over. And good luck eating 4,000 calories from minimally processed foods. You'll quite frankly be miserable because you're going to have such gut fill that you're going to feel like you can't even move. And so that's why I'm so pedantic and a stickler about saying: yes, it's a good idea to eat minimally processed foods and try to avoid processed foods — but not because processed foods are bad per se, but because of what the outcome tends to be from a lot of processed food consumption, which is over-consuming calories and therefore energy toxicity negatively contributing to your health.
Artificial Sweeteners — Changing Views and the Real-World Evidence
Huberman: This I think is a perfect segue for something that first brought us together, which was this thing about artificial sweeteners. Artificial sweeteners are many things. I'd like to talk about their effects on blood sugar in the acute sense, and then the gut microbiome data, which I think are interesting enough to discuss. I have changed my view on artificial sweeteners based on what you've taught me. This is a case where I've completely changed my view — which is that I don't have any problem with them whatsoever based on the current data. Which is not to say that I'm gulping down cupfuls of sucralose, but I feel okay ingesting some stevia and some aspartame and I'm not too worried about it.
Norton: We have to think about the hierarchy of importance, and what are you replacing them with? There is no situation where it is not a net positive to take somebody who drinks sugar-sweetened beverages and have them drink an artificially sweetened beverage. There was a recent network meta-analysis looking at markers of adiposity, HbA1c, and a bunch of different health markers, and when you substitute — we'll call them non-nutritive sweeteners, since stevia is not artificial — when you substitute non-nutritive sweeteners for sugar-sweetened beverages, you see improvements in a lot of different things. And whenever I post about non-nutritive sweeteners in the comments, there are always one or two or three people who say, "All I did was cut out soda and drank diet soda instead, and I lost 50 pounds, or 75 pounds." I even had one person say they lost 100 pounds. That's the only thing they did.
Huberman: Wow.
Norton: I mean, that's a pretty massive lever to pull if you consider somebody who might be having five or six Cokes a day. We're talking a serious amount of calories. Is that obese person who lost 100 pounds by doing that — do I really care about maybe a small alteration to their gut microbiome? No. Because their gut microbiome is actually much more healthy now by them having lost all that excess adipose tissue. So I think it's one of those things that again depends on the situation. If somebody's obese and this is going to help them eliminate sugar-sweetened beverages — why would you want to take that tool away from them? That's a great lever to pull. If somebody can lose literally 100 pounds from just one change in lifestyle that's not even really that inconvenient, that is powerful. But again, is it the most healthy thing they could do? We don't know. Is it healthier than water? Probably not. Maybe as healthy? Who knows. But I really make all those caveats because you don't want people who could use this as a tool to think, "No, I can't do this because it's actually bad for me." If it helps you lose 50 or 75 pounds or whatever it is, trust me, it's not bad for you.
Seed Oils — Evaluating the Evidence
Huberman: Seed oils. There are a number of folks out there who are arguing that seed oils are the source of the obesity epidemic and everything. And then there are those who would argue just the opposite — that meat is the source of all problems. And I think we've appropriately framed things so that it's never that black and white. Are there any data on seed oils?
Norton: The first thing I'll say is seed oils have negatively contributed to our overall health because what people in the last 20 to 30 years have tended to add into their diet that has increased the overall calorie load is oil — mostly from seed oils. But when we look at one-to-one replacement with other fats — if you look at the epidemiology, yeah, you can find some epidemiology showing people who consume more seed oil have more negative health outcomes. The problem is again it's tied up with a multitude of other behaviors. And then you can find mechanisms. The idea is: they're polyunsaturated, which means in the fatty acid chain there are multiple double bonds, and those double bonds can be oxidized when exposed to heat and some other things. So the idea is, when you cook with these things, they may get oxidized and that's going to cause inflammation in your body. That's a plausible mechanism.
So as always, I defer to the human randomized controlled trials. What you tend to find when you substitute saturated fats for polyunsaturated fats is that inflammation is basically neutral. There are some studies that show a positive effect of doing polyunsaturated fats, but it probably depends on the individual polyunsaturated fat. And that's the other thing — it's difficult because you're categorizing everything in one bucket, and there are some differences between individual fatty acids. Even with saturated fat, for example, stearic acid doesn't tend to raise LDL cholesterol, whereas saturated fat as a whole tends to raise LDL cholesterol. So again, we're putting things in buckets and it's a little more nuanced than that.
If you look at the effects of polyunsaturated fats on markers of cardiovascular disease, it again tends to either be neutral or positive when you substitute saturated fat for polyunsaturated fat. Now, if you want to get into monounsaturated versus polyunsaturated, there's quite a bit of disagreement between the studies. What I would say based on the human randomized controlled trials is that you're probably better off consuming monounsaturated and polyunsaturated in place of saturated fat. But again, if the idea is, "Well, that means polyunsaturated are good for me, so I'm just going to dump a bunch of oil on everything" — now you're upping your calories, and that's a negative because you have to deal with the bigger problem of overall energy toxicity.
I'm not somebody who likes to demonize individual nutrients. I just haven't seen really compelling evidence that seed oils are the root cause of the problems being suggested. And I think this is a good example of what tends to happen in the fitness industry — there's always the opposite thing that pops up as a reactionary extreme response to whatever was over here. And I think that's what we're seeing with some of the seed oil stuff. It's mostly people who are trying to expose the virtues of saturated fat. I think it's fine to consume saturated fat, but limiting it to 7 to 10% of your daily calorie intake is probably wise, again based on the consensus of the evidence I've seen. So once again, we're struggling with epidemiology and mechanisms that sound good, but then what actually happens when we do human randomized controlled trials — and so far I just haven't seen the evidence to suggest that seed oils are independently bad for you, independent of the calories they contain.
I think we all have this idea that there's this one iconic diet out there that is going to be the best diet for building muscle and burning fat and preventing cancer and heart disease. And the reality is there are overall healthy dietary patterns that we see that are good for those things. But when we get down into the weeds, there's probably some push and pull as well.
Creatine Monohydrate — The Most Tested Supplement
Huberman: I'd like to ask you about supplements for a moment. One that I'm very familiar with is creatine monohydrate — not just for muscle building, but maybe any other purposes for it.
Norton: It is the most tested, safe, and effective sports supplement we have. There are thousands of studies on creatine monohydrate now. I would say very clearly too: if you're using any other form of creatine, I think you're wasting your money. Creatine hydrochloride has some hype around it — it's apparently a little more soluble, and the claim is that you need less — but there are only a couple of studies on it and it's more expensive. So I tell people just take creatine monohydrate. It is tried and true. It's been shown to saturate the muscle cells 100% with phosphocreatine, and that's what you want.
Creatine works through a few different mechanisms. One, through increasing phosphocreatine content, which helps improve exercise performance. It appears to improve recovery, and it increases lean mass — a lot of which is through bringing water into the muscle cells. But that is — I mean, muscle cells are mostly water. So when people say, "Well, it's just water," that's what muscle cells mostly are. It also increases strength and some other metrics. Now, it's also been shown in studies that people tend to get a decrease in body fat percentage. That's probably because they're getting an increase in lean mass, so the relative proportion is a decrease in body fat percentage. But there are a few studies that show a decrease in fat mass as well. I don't think creatine is a fat burner. I think people are able to train harder, build more lean tissue, and so that's probably having an effect on fat mass. Then, more recently, they've actually shown some cognitive benefits to creatine, which I find really interesting as well.
The only knock on creatine that anybody's been able to come up with — because they've debunked the kidney stuff, they've debunked the liver stuff, there's no evidence that it harms healthy kidney or liver — is hair loss. So what about hair loss? There was one study in 2009 that showed that creatine increased DHT. But they didn't really show an effect on any other sex hormone, which is kind of strange — you would think if there was an increase in DHT there would be something else that changes as well. And it's only one study, never been replicated to my knowledge, and it was looking at a mechanism rather than an outcome. What I would say is that I am not convinced — it's only one study, never been replicated, and it was looking at a mechanism rather than an outcome.
Huberman: Do you emphasize the classic loading of creatine — taking it a bunch of times per day and then backing off — or just taking it consistently at, say, five grams per day?
Norton: No solutions, only trade-offs. You can load it and you will saturate your phosphocreatine stores faster — usually within a week. If you just take five grams per day, it'll take two, three, four weeks. But you will get to the same place, and you're probably going to have a much lower risk of GI issues. Some people find creatine can be a gut irritant. If it is for some folks, I would recommend splitting it into multiple doses — maybe multiple one or two gram doses per day — and definitely don't load it if you're somebody who has GI issues from it.
The Importance of Hard Training Over Optimization
Norton: The more into the weeds people tend to get — and again this is just my own anecdote and observation — the less hard I see them train. And so one of the things I really like that Mike Israetel said — who has a PhD and is a bodybuilder himself — he said, "You can't outscience hard training." If you're looking to build muscle and improve your body composition, the main thing is just doing the work over time. And I think a lot of that is getting the confidence that comes from doing something hard and finding there's a payoff at the end. I get asked a lot in my Q&As, "How do I get more confident? How do I become more confident?" I'll tell people: there's no hack, you can't read about it, you've got to get in the arena. And I don't mean necessarily compete in sports, but doing a PhD, or doing something just something hard where you're putting yourself out there and saying, "This is my goal and I'm going to go for it." You just learn so much by doing that about yourself.
Huberman: I must say this conversation for me has been tremendously rewarding. The amount of knowledge that you contain inside you is astonishing.
Norton: There's a lot of stuff rattling around up there.
Huberman: Your ability to pull from the mechanistic side — related to your background in biochemistry — all the way through to the impact in humans, animal studies, being able to understand where those sit relative to one another. And then you're obviously a practitioner — you practice what you preach. And what you talk about pertains to men, to women, younger people, older people, people who are vegan, keto, carnivore. You really are able to net a tremendous number of ideas while staying really nuanced and data-driven. So just want to say, for myself and on behalf of the listeners, really appreciate you coming in here today and sharing your knowledge. Thank you so much for your time.
Norton: Oh, thank you. I appreciate the opportunity. I really enjoyed it.