Essentials: The Science of Eating for Health, Fat Loss & Lean Muscle | Dr. Layne Norton

See Andrew Huberman live in New York, Los Angeles & San Francisco:

Welcome to Huberman Lab Essentials, [music] 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 opthalmology at Stanford School of Medicine. And now for my discussion with Dr. Lane 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 in fitness and nutrition in a number of areas. I’d like to start um 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?

It’s a great question and like you said this is one of those things where you know 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, right? And by digesting, assimilating and metabolizing those nutrients, we are able to create energy. The inroduct of that mostly is ATP, adenazin triphosphate, which is your body’s energy currency.

So a lot of metabolism is simply creating ATP. Protein’s a little bit different because protein uh gets converted to amino acids which can be used for muscle protein synthesis or protein synthesis in other tissues. Uh but it also can be converted through glucanogenesis 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 you’re lpping them off two carbons at a time to produce acetal coa which again can go into the KB cycle produce those hydrogen ions that can then power the production of ATP. So that’s kind of like at the cellular level of how this stuff works.

But stepping back and taking it back out like what does that have to do with weight loss or weight gain, right? When you think about the balance of energy in versus energy out, 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 inside of the equation is more difficult to track than people think. So, one, food labels, which we like to think is being, you know, like from upon high, uh, can have up to a 20% error in them.

Really? >> Oh, yeah. The second aspect is there’s what’s called your energy but then there’s also metabolizable energy right so if you have uh food stuff with say a lot of insoluble fiber typically insoluble fiber uh is not really digestible and so you could have you know quite a bit of carbohydrate but if you can’t extract the energy from it and typically this is because insoluble fiber from like plant material the carbohydrate or and even some of the protein is bound up in the uh plant structure which makes makes it inaccessible to digestive enzymes. And so this is what like adds bulk to your school stool and whatnot, but again reduces the metabolizable energy in there. And there’s some evidence that based on people’s individual gut microbiome that some people may actually be better at extracting energy out of fiber compared to other people.

So just starting off right there, okay, there’s there’s quite a bit of play in the energy inside of things. Now, one of the things people will say is, “Well, see, that’s why you shouldn’t worry about tracking calories, cuz you know, 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. So, now let’s look at the energy out side of the equation, which is actually way more complicated, right? And so, your energy out is a few different uh buckets.

The first one and the biggest one is your resting metabolic rate. So your arm rar that 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. It’s about 5 to 10%. Very difficult to measure. And usually what researchers do when they’re kind of looking at this stuff is they just kind of make an assumption about it.

They use a constant. And that refers to the amount of energy it takes to extract the energy out of food. You can’t just eat food and then you know it just appears in your cells and you start doing stuff. 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, well, not all calories are created equal.

That’s not true because calories is just a unit of measurement, right? That would be like saying not all seconds on a clock are created equal. Yes, they are. All sources of calories may have differential effects on energy expenditure and appetite. So if we look at something like fat for example, the TEF of fat is about 0 to 3%.

Meaning if you eat 100 calories from fat, your net will be about 97 to 100. So the process of breaking down that fat essentially subtracts some of the the calories away because you used it in creating energy correct by breaking those chemical bonds to create ATP. >> Correct. Okay. Correct.

Fat is actually the easiest thing to convert into energy. >> Then you have carbohydrate which has a TF of like 5 to 10%. So you eat 100 calories from carbohydrate and obviously like the fiber content makes a big difference on this. But if you eat 100 calories you’ll net 90 to 95. protein is about a 20 to 30% TEF.

So if you eat 100 calories from protein, you’re only netting 70 to 80. Now you’re still net, you know, people say, well, you can’t eat too much protein. Well, you know, people will ask, well, can protein be stored as fat? The carbons from protein, it’s unlikely it’s going to wind up in atapost 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 in fat. But protein itself does provide you know a net positive for calories but less so than carbohydrate or fat and tends to be more satiating.

So again when people talk about you know are all calories created equal yes but all sources of calories may have differential effects on energy expenditure and appetite. So that’s the TEF bucket and the BMR bucket. Then we go to physical activity. And physical activity is essentially two parts. There’s exercise which is kind of your purposeful movements like you go out for a walk, you do a training session, I mean whatever any purposeful activity and then you have what’s called NEAt which is non-ex exercise activity thermogenesis.

So for example if I when I’m talking if I’m waving around my hands if I’m tapping my feet if I’m whatever that’s NEAt the calorie burn from NEAT is actually pretty significant. We’re not talking about 100 calories or 200 cal