Huberman LabDr. Andy Galpin: How to Build Physical Endurance & Lose Fat | Huberman Lab Guest Series
EVERY SPOKEN WORD
155 min read · 30,816 words- 0:00 – 7:30
Endurance: Benefits, Mechanics & Breathing
- AHAndrew Huberman
(Upbeat music) Welcome to the Huberman Lab Guest Series, where I and an expert guest discuss science and science-based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today's episode is the third in the six-episode series on fitness, exercise, and performance. Today's episode is all about endurance and fat loss. That is, the specific protocols required to achieve the four different kinds of endurance and how to maximize fat loss. Dr. Andy Galpin, great to be back. Today, we're going to talk about endurance, and I'm very interested in this conversation because I, like many other people, strive to get a certain amount of cardiovascular work in each week, maybe a long-ish jog, maybe a swim, ride the bike, et cetera. But when I think about the word endurance, the idea that almost immediately comes to mind is about doing something for a long period of time repeatedly, but I have a feeling that there are other ways to trigger this adaptation that we call the endurance adaptation. So, I'm excited to learn about that. I'm, uh, also excited to learn about the fuel systems in the body that allow for endurance and other modes of repeated activity. So, in order to kick things off, I'd love for you to frame the conversation by telling us, what is endurance and are there indeed a large variety of ways to induce what we call this endurance adaptation?
- AGAndy Galpin
Sure. The way I want to start actually here is, is calling back to some of the things we talked about in our previous conversations, which are really, people ha- exercise for three reasons. Number one, you want to feel better. Number two, you want to look a certain way. And then number three, you want to be able to do that for a long time, right? So you need to went- the way that we say it in sports is look good, feel good, play good, right? So I want some sort of functionality to be able to perform a certain way, whatever that is for you. You want to be able to look a certain way that, whatever that matters for you, and then you want to be able to do that for a long time. So when it comes to endurance, we have a bunch of misnomers here, which is the same thing with the strength training or resistance exercise side, where, where we wanted to dispel this myth that I lift weights only because I, I want to gain muscle or play a sport, and I want to do cardio because I want to either lose fat or for long health's sake. And just like we smashed that myth from the strength training side, I want to smash it from the endurance training side. There are so many other reasons that you want to perform endurance training regardless of your goal, right? Whether that is longevity, whether it is performance, or whether it is aesthetics. And so we're gonna, I wanna cover all those reasons, uh, exactly what to do, uh, protocols, of course, a- and why those things are working that way. In general though, the quick answer is really endurance comes down to two independent factors. Factor number one is fatigue management and then factor number two is fueling. And that's all it really comes down to. So all the different types of training are going to reach a limitation, which are either, again, your ability to deal with some sort of fatigue, and that's generally a fatigue signal. The other one is managing some sort of restriction of energy input. And a lot of the... Spoiler here is, a lot of the times people think it's a fueling issue when really it's a fatigue management issue or the opposite. And to have a complete health spectrum, regardless of whether you're a high performance athlete like I typically deal with or general public, you need to be able to do both, manage fatigue as well as understand fuel storage. So that's really what we're gonna get into today.
- AHAndrew Huberman
Fantastic. I can't wait. Before we dive in, I'm going to ask you what I often ask people who are expert in their respective fields, which is, is there any non-obvious tool or mechanism or tool and mechanism that can allow people to access better endurance? You know, when I think about training for endurance, again, I s- think about trying to run longer and longer each week-
- AGAndy Galpin
Mm-hmm, yeah.
- AHAndrew Huberman
... or swim further and further and so on. But I do wonder whether or not there are other forms of training that can amplify the endurance adaptation that I or most people perhaps don't think of as endurance.
- AGAndy Galpin
Sure. The way I want to answer this is, if we look back and think about how we've answered that question with power and strength, uh, and force production, it is really about how much can you produce maximally once. What you're asking now is how can I repeat that same quality of performance? If that's the case, endurance really comes down to your ability to maintain proper mechanics. That's going to, like, the, the biggest way we can, uh, increase your endurance exponentially very quickly is mechanical. And this is starting with breathing. And so we need to be breathing properly, we need to have proper posture and positions, and then we need to be moving well. Efficiency is going to trump force always for endurance. The other side of the equation is not that. You can have a little bit of leaks in your mechanics and still squat well or jump high and be fine because you don't have to suffer those consequences repeatedly, right? That's going to drain you over time. So, uh, the quickest way to improve endurance is to improve mechanics, and the mechanical thing I would go after first is your breathing techniques, your pattern, your entire approach, as well as your posture, and then from there, the third one would be your movement technique.
- AHAndrew Huberman
Is it possible to describe the best way to breathe when doing endurance training or is it far more complex than that? And if it is far more complex than that, then certainly we can get into it during today's episode.
- AGAndy Galpin
Yeah, it is both of those. I will give you a quick answer though. Uh, a lot of the times, you can kind of hit the cheat code, which is nasal breathing. There, there's plenty of times when you don't want to nasal breathe or don't need to nasal breathe, but just, again, as a, like a one tool that is a sort of a pretty general answer, if you can do that, a lot of the times that will fix breathing mechanics just by default. And, and we can maybe talk about why that is later, but that would be my sort of one sentence bullet point answer immediately, uh, of how to get in the right position. The second one would be simply looking at your posture.... right? So whether you're on a bike, or you're, uh, doing a lift, or you're running, if you're literally, uh, hunched over and your ribs are touching your femur, or getting closer and closer, like, uh, tends to happen on a bike or an air assault thing for somebody I've seen recently.
- AHAndrew Huberman
This morning, uh, I was on the assault bike, um, doing a, a sprint, um, and I asked Andy, Dr. Galpin, to, uh, critique my form and anything else he wanted to critique so that I could improve. And he did comment on my rather C-shaped posture-
- AGAndy Galpin
Correct.
- AHAndrew Huberman
... um, encouraging me to be, uh, be more upright-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... which I should probably do now as well. And he also cued me to the fact that during a one-minute sprint, there is something that is, quote-unquote, "magic" that happens right about the 40-second mark-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... and I used that as a, um, as a milestone, uh, to look for. And indeed something does happen at the 40 seconds into a one-minute sprint where all of a sudden it, it does seem to get much easier for reasons I don't understand. Maybe you can tell her that. But it certainly had nothing to do with my posture. My posture needs improvement.
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
Thank you.
- AGAndy Galpin
Well, yeah. So, um, breathing mechanics and breathing strategies. Uh, people tend to be over-breathing early on. And this is gonna lead to problems later. So having a more strategic breathing pattern, uh, and approach i- is, again, a very quick solution.
- AHAndrew Huberman
I know that we are going to dive very deep into the mechanisms of energy and metabolism-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... and endurance today.
- 7:30 – 14:21
Tool: “Exercise Snacks”
- AHAndrew Huberman
But as long as we're ha- having a discussion about these, um, brief sort of tidbits of how to improve endurance, are there any other ways to improve endurance that are of relatively short time investment, even if they require a lot of, um, energy?
- AGAndy Galpin
Sure. The classic paradigm you're gonna find here is steady state long duration posed up against what a lot of folks will now call higher intensity interval training specifically. And there's a lot of misconceptions here. The quick answer is you need to be doing both. And there's probably a bunch of stuff in between that you should be practicing. If you honestly want to maximize those three factors we talked about at the beginning, you need to be training across this full spectrum. Just like I told you to train across the full spectrum of your lifting, we want to be doing the same thing here. So are there independent special factors, uh, that can happen with the shorter time length, higher intensity stuff? Absolutely. There's also magic that happens on the other end of that spectrum. So it's very important, um, that people don't just choose one side. Because what tends to happen is people either go with the, "Oh, I'm gonna do 30 or 45 minutes of steady state stuff, that's it," or, "I'm gonna do the opposite, which I'm gonna leave that stuff on the table, not do it, 'cause I only want to do high intensity intervals 'cause I can get it done in five minutes." So there's magic on both sides of the equation. We want to get into all that. Um, but just to answer your question directly, there's a whole bunch of, of things you can do, um, in under one minute, um, that are convenient to do. And there's a, uh, a wonderful set of papers, um, out of a couple of laboratories in Canada that, that championed this idea that's called exercise snacks. So there's a bunch of, there's a series of studies that have been done here that are really interesting. And th- they've looked at a couple of things that are noteworthy. One of them is a 20-second bout of all-out work. And this is actually done in workers in an office. And so what they had them do is run upstairs. And I believe it was about 60 steps is, is what it took them. Something along the order of 20 seconds exactly. And they repeated that, um, about once every four hours. So really it's just you go to work, you get, you know, put your coffee and your bag down, whatever, you run up a flight of stairs, 20 seconds later then you go right back to work. At lunch and before you go home, you sort of repeat it there. Um, and if you repeat that, that's multiple times a week you're gonna do that. I think they, in one of the interventions it was three times a week for six weeks. 18 total times you did that. And what you'll see is, um, a, a noticeable improvement, and this is statistically significant, improvements in cardiorespiratory fitness, specifically VO2 max, as well as a number of cognitive benefits, work productivity, et cetera. That can happen in as little as 20 seconds. You don't have to go to the gym, you don't have to shower, you don't have to do anything like that. Just find the stairs, um, run up and down them a few times. Now you may have noticed, um, you actually sort of caught me (laughs) yesterday, I did that right here, right? I was just... I... uh, we had a little bit of a break. I was feeling an energy lull. I ran up the stairs three or four times, felt s- uh, a lot better. So that can actually also help. They ran another study where they looked at that following a giant high-glycemic index meal. And what they saw, and then th- they took insulin measures and, and a whole bunch of, um, other biological markers associated that you, you want to be paying attention with a high-glycemic index meal. And they looked at those immediately, an hour, three hours, six hours as a post. And it was very clear that same intervention was able to improve postprandial glucose control, insulin, and a whole bunch of other factors, um, in addition to that. So if you are the sort of type who's like, "Wow, I'm in an office all day," maybe also had a giant, uh, high-glycemic index meal, uh, not the best approach, but a little bit of mitigation there can just be running up a flight of stairs or doing something like that for as little as 20 seconds. So there's a lot of magic and power in maximal exertion.
- AHAndrew Huberman
If one does not have access to a flight of stairs at work, could they do jumping jacks?
- AGAndy Galpin
Absolutely. I mean, you could do anything you really wanted. Um, it's not the mode of exercise that matters here. It is simply the exertion. Um, you just get up as, as hard as you can. You could do burpees, you could do any number of things. Um, you could sprint down your road, down the hallway back and forth. Um, the mode is, is just, uh, something that was easy for the scientists to control. And X number of steps, people could do it, you're not gonna fall, hurt yourself, things like that.
- AHAndrew Huberman
Just to remind me, it's once every four hours, one minute of all-out-
- AGAndy Galpin
20 seconds.
- AHAndrew Huberman
Oh, 20 seconds. Excuse me.
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
Uh, 20 seconds of essentially all-out exertion-
- AGAndy Galpin
Yep.
- AHAndrew Huberman
... while remaining safe.
- AGAndy Galpin
Yep.
- AHAndrew Huberman
Not going so fast up the stairs or doing jumping jacks so fast that-
- AGAndy Galpin
And certainly not down the stairs. Up the stairs please.
- AHAndrew Huberman
Right. Um-... escalators-
- AGAndy Galpin
(laughs)
- AHAndrew Huberman
... don't count. Well, I suppose they count if they're, uh-
- AGAndy Galpin
Just run up them.
- AHAndrew Huberman
... you know, if you're, if you're moving, uh, if you're not remaining on the same steps. Um, in fact, in an airport recently, I saw somebody walking against the, uh-
- AGAndy Galpin
Oh, there you go.
- AHAndrew Huberman
... the conveyor-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... while talking on the phone while waiting for their flight to take off.
- AGAndy Galpin
Love it.
- AHAndrew Huberman
And I thought, "It's genius," right?
- AGAndy Galpin
Love it.
- AHAndrew Huberman
It looked a little awkward, but-
- AGAndy Galpin
Who cares?
- AHAndrew Huberman
Yeah, but it was, uh-
- AGAndy Galpin
I have looked awkward-
- 14:21 – 18:01
Momentous, Levels, LMNT
- AGAndy Galpin
- AHAndrew Huberman
Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is also separate from Dr. Andy Galpin's teaching and research roles at Cal State Fullerton. It is, however, part of our desire and effort to bring zero cost to consumer information about science and science-related tools to the general public. In keeping with that theme, we'd like to thank the sponsors of today's podcast. Our first sponsor is Momentous. Momentous makes supplements of the absolute highest quality. The Huberman Lab Podcast is proud to be partnering with Momentous for several important reasons. First of all, as I mentioned, their supplements are of extremely high quality. Second of all, their supplements are generally in single ingredient formulations. If you're going to develop a supplementation protocol, you're going to want to focus mainly on using single ingredient formulations. With single ingredient formulations, you can devise the most logical and effective and cost-effective supplementation regimen for your goals. In addition, Momentous supplements ship internationally, and this is, of course, important because we realize that many of the Huberman Lab Podcast listeners reside outside the United States. If you'd like to try the various supplements mentioned on the Huberman Lab Podcast, in particular, supplements for hormone health, for sleep optimization, for focus, as well as a number of other things, including exercise recovery, you can go to Live Momentous, spelled O-U-S, so that's livemomentous.com/huberman. Today's episode is also brought to us by Levels. Levels is a program that lets you see how different foods and activities affect your health by giving you real-time feedback on your blood glucose using a continuous glucose monitor. Many people are aware that their blood sugar, that is, their blood glucose level, is critical for everything from fat loss to muscle gain to healthy cognition, and indeed, aging of the brain and body. Most people do not know, however, how different foods and different activities, including exercise or different temperature and environments impact their blood glucose levels. And yet blood glucose is exquisitely sensitive to all of those things. I first started using Levels about a year ago as a way to understand how different foods, exercise, and timing of food relative to exercise, and quality of sleep at night impact my blood glucose levels, and I've learned a tremendous amount from using Levels. It's taught me when best to eat, what best to eat, when best to exercise, how best to exercise, and how to modulate my entire schedule from work, to exercise, and even my sleep. So if you're interested in learning more about Levels and trying a continuous glucose monitor yourself, go to levels.link/huberman. That's levels.link/huberman. Today's episode is also brought to us by LMNT. LMNT is an electrolyte drink that contains the exact ratios of the electrolytes sodium, magnesium, and potassium to optimize cellular functioning for mental and physical performance. Most people realize that hydration is key. We need to ingest enough fluids in order to feel our best and perform our best, but what most people do not realize is that the proper functioning of our cells and nerve cells, neurons in particular, requires that sodium, magnesium, and potassium be present in the correct ratios. Now, of course, people with pre-hypertension and hypertension need to be careful about their sodium intake, but what a lot of people don't realize is that if you drink caffeine, if you exercise, and in particular, if you're following a very clean diet, that is, not a lot of processed foods, which, of course, is a good thing, chances are, you're not getting enough sodium, potassium, and magnesium to optimize mental and physical performance. LMNT contains a science-backed ratio of 1,000 milligrams, that's one gram of sodium, 200 milligrams of potassium, and 60 milligrams of magnesium, and no sugar. If you'd like to try LMNT, you can go to DrinkLMNT, that's lmnt.com/huberman, to get a free LMNT sample pack with your purchase. Again, that's Drink LMNT, lmnt.com/huberman, to claim a free
- 18:01 – 22:16
Endurance Categories
- AHAndrew Huberman
sample pack. So tell me about endurance. What is endurance, how do I get more endurance, and how does it work?
- AGAndy Galpin
When we think about endurance, I would like to open up the conversation to include more things tha- than people generally do when they hear the word endurance. So, if we just think about what you typically ask your body to do, or would like to ask your body to do, and we just walk through them, it's gonna be things like this. Number one, I want to have energy throughout the day. That's actually a form of endurance. Great. I don't want to have these lulls in fatigue, and I want to feel fantastic as I move throughout my activities of daily living, whatever those may be. Work, exercise, enjoyment, cogni- paying attention, focus, all that stuff. Great. That's one thing. Another thing you want to ask your body to do is, I want to be able to repeat some small effort in a muscle group and not, and, and feel great about that. This is what we generally call muscular endurance. So, this is something like, I want to be able to walk up those 10 flights of steps and my quads aren't burning at the end of it, right? Or, it's even, gives me energy. Another thing you'll want to ask your body to do is to be able to perform a tremendous amount of work for a longer period of time. Something in the realm of, you know, 20 to 80 seconds. So, this could be something like if you're surfing and you've got to paddle extremely hard for a minute to get on- on top of a wave. Or you wanna, you gotta, you're out riding your bike and you need to be able to get up a hill and it's a very steep hill. These are gonna take maximal effort, um, for some small amount of time and then you'll get back up there. We tend to call that maximum anaerobic capacity. So, the- the max amount of work you can perform at a high rate for some amount of seconds to m- like maybe a minute. Past that is your ability to repeat an effort kind of like that for something like five to 15 minutes, and this is, the example would be run a mile, right? Some- some interval like that which is a longer distance, right? Um, that is gonna be your maximum aerobic capacity. Okay? Another thing you're gonna want your body to do is what we call sustain position. So, this is you want to be able to sit in your chair at work and have perfect posture for 20, 30, 40 minutes, right? You want to be able to stand in line at a grocery store for 15 minutes and not have a breakdown in posture. So, you wanna be able to maintain position when you're riding your bike, you're not collapsing, you're doing any of these activities and you don't get hurt or lose efficiency simply because you couldn't sustain basic positions. All right? Whatever those shapes and positions need to be. Okay? And then the last one is a- a maximum distance. So, you want to be able to go for a- a longer hike or have just a long day at Disneyland for whatever it needs to be and feel great at the end of it. Right? So, the goal with all of these things is not can you just do them, but can you do them and then you feel good afterwards? So, we're back in a right position where they give you energy, you feel good about it, and it's not just something you had to do and you regretted and you felt awful. So, those are the factors I think about when someone says, "I want better endurance," is I- I wanna walk backwards and say, "Okay, when you say endurance, what do you mean?" And that's generally the things I've come across is if you can handle all of those things, you're gonna feel like you're in fantastic shape. You're gonna feel, your recovery's going to be excellent and your physical performance in the gym or in any of the sporting activities you do will be enhanced.
- AHAndrew Huberman
Given what you told us a little bit earlier, that endurance really reflects fatigue management and energy production, how do each and both of those things relate to endurance at a mechanistic level?
- AGAndy Galpin
Sure.
- AHAndrew Huberman
I mean, really, what I'm asking is, what is fatigue management and what is energy production?
- AGAndy Galpin
In order to do that, it's important that we understand all of those functional capacities that I just talked about. They all have different points of failure. Okay? So, in order to then work backwards and say, "Well, how do I optimize my performance in all those categories?" we need to go through each one and figure out, well, where am I failing? Some of them are gonna be failing because of fatigue management and some of them will be failing because of energy production issues. So, if we walk through a little bit of how we make energy and how we handle fatigue, then we're gonna have a better understanding of exactly what to do for each one of these categories if you feel like one of them in particular is, uh, worse for you or lagging behind, or if, in general, you just want to improve
- 22:16 – 33:08
Fat Loss & Respiration; Carbon Cycles & Storage, Metabolism
- AGAndy Galpin
all of them. All right. Now, I'm gonna make a little bit of a 90-degree turn here. I'm gonna do it with strategy though, I promise, and I wanna ask you a very simple question. How do you lose weight?
- AHAndrew Huberman
I was taught that the calories in, calories out thermodynamics of energy utilization (laughs) governs most everything. That is, if I'm ingesting less caloric energy than I burn, then I'm going to lose weight. And if I'm ingesting exactly as much as I burn, I'll maintain weight, and if I ingest more than I burn, then I'll gain weight.
- AGAndy Galpin
Sure. That is the approach you would take. What I'm asking really is how are you actually physically losing the weight?
- AHAndrew Huberman
So, my understanding is that we have different fuel sources in the body. Glycogen, which is stored in muscle and liver. Body fat, which is stored in mainly white adipose tissue and s- which is subcutaneous and around our organs, intraviseral fat, and that we can also use protein as a fuel. And then, as I recall, there's also a phosphocreatine-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... system. And I think you're going to tell me that each of these systems is tapped into on different timescales and perhaps according to different levels of exertion. And I'm certain that what I just said is not exhaustive, but hopefully it is most or entirely correct.
- AGAndy Galpin
Pretty correct. What's that got to do with fat loss?
- AHAndrew Huberman
Uh, at some point, uh, body fat stores adipose, uh, adipocytes, fat cells, are going to start liberating fat as a fuel source and the stimulus for that, I'm assuming, is going to be that other fuel sources a- are either depleted or that the energy and metabolic systems of the body, I don't want to say decide because they don't have their own consciousness-
- AGAndy Galpin
Sure.
- AHAndrew Huberman
... but are, um, are flip-
- AGAndy Galpin
Signal.
- AHAndrew Huberman
... are signaling in a way that registers that, uh...... body fat would be the optimal fuel source given how long or inte- and/or intensely a given activity has been performed.
- AGAndy Galpin
Okay. We have some stuff to clean up there, but we're still not really answering the question. How am I actually losing that body fat?
- AHAndrew Huberman
Uh, how is it actually leaving the body?
- AGAndy Galpin
Correct.
- AHAndrew Huberman
Uh, my understanding is that it leaves the body through respiration.
- AGAndy Galpin
Ah-hah. So now, we have some interesting things to talk about. How am I actually losing fat via respiration? What the hell does that even mean? How is something that occupied this physical space on the side of me leaving my body through my mouth? And there's a very clear answer there, right, which I'm, I'm sure you're cued up to. When you take a breath in, you're generally breathing in oxygen, O₂. There's some other things, but we'll just stick to oxygen. When you exhale, you're breathing out CO₂. The difference between those two is that carbon molecule. Well, one of the things that's important to understand here is all of your carbohydrates, which is tho- that word itself is a carbon that has been hydrated, so it is a carbon molecule attached to a water molecule. It is a simple chain of carbons. Your fat molecules are also chains of carbon. All of metabolism, really, in terms of energy production, is simply trying to figure out a way to break those carbon bonds. As a result, we get energy from that. We use that energy to create a molecule called ATP, which is the central source of energy for any living being, right? That carbon is then floating around in free form, which is bad news internally. So we've got to figure out a way to get that carbon out of our system. So all of energy production, all of fatigue management really comes down to this core issue of, how are we handling carbon? And how are we moving it around the body? And so what we do is we do this sneaky thing. So another question I like to ask people is, why do we breathe?
- AHAndrew Huberman
Well, for two reasons, uh, to bring oxygen into the system and to offload carbon dioxide. But the neural trigger for breathing is when carbon dioxide hits a threshold level and the set of neurons in the brain stem and elsewhere-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... uh, activate the phrenic nerve, or the gasp reflex, or a combination of things, and we (inhales sharply) inhale or inhale.
- AGAndy Galpin
Right. So a reduction of oxygen intake generally doesn't stimulate ventilation unless you're at altitude, then that sort of changes, right? In general, it's an elevation in CO₂ that's gonna stimulate breathing up. The only reason you bring in O₂ for the most part is to get rid of the CO₂. Oxygen is not a fuel source. It is not a way... A- and it works the same with fire, by the way. So you know you have to have oxygen present for a fire to go, and if you squelch oxygen, the fire will go out, right? That's how half of, um, how those, like, fire extinguishers work. But we think then that means oxygen is the fuel. It is not the fuel. It is something entirely different. It is a necessary pro- uh, it is a product that is necessary for the metabolism process to actually occur. All right, so we're, we're kind of dancing around an idea here, which is this carbon cycle of life. So, what happens in plants is they generally will breathe in the opposite and breathe out the opposite of humans. So a plant will breathe in CO₂ and exhale O₂. All right? This is why we have to have a certain amount of these things in algae and forests and trees and stuff to maintain this O₃, CO₂ balance in our atmosphere. We do the opposite, and so we have this wonderful circle of life. We breathe in O₃, breathe out CO₃. They do the opposite. Well, what happens is, because carbohydrates are long chains of carbon, and fats are as well... Generally when we think about fats, by the way, it's important to understand that structure a little bit. So if we think about triglycerides, um, it is a three carbon backbone chain of glycerol, so it's one, two, three. And horizontally running off of each one of those are fatty acid chains, right? And so we form this structure that looks like an E, right, like the letter E, three in the back and then three chains coming off of it. Each of those chains are called fatty acids, and each of those fatty acids are a length of carbon, right, or are a number of carbons strung together. However many carbons are there determines which type of fatty acid it is, right? So stearic acid, linoleic acid, like any different number of things. It's also what determines whether or not it is a monounsaturated or polyunsaturated is if, um, carbon requires a special thing called a double bond. So if there's a double bond across every carbon and carbon, then they're all fully saturated and you're great. If there's any of them that are not double bonded, and in fact an example, if there is one that doesn't have a double bond, that is now called monounsaturated. And if there are many, it is called polyunsaturated. So there's pros and cons to all of these things. Right. In either case, we're still talking long carbon chains. So what a plant will do is bring in carbon, and then it has this wonderful ability to use energy from the sun called photosynthesis. And it can take those carbons that it inhales and use the energy from the sun to form a bond. Now, in our prior discussion when we were, uh, going over hypertrophy, we talked about the energy that was required to go through protein synthesis. That's because forming a new atom, uh, or a new bond between atoms oftentimes takes energy. In these cases it does. The same thing happens here. So if a plant does not have oxygen or does not have carbon dioxide in the air, it has no fuel. The... Basically, think about it as that's what it eats. It needs to get nitrogen from the ground and the soil, just like we need to get nitrogen from our protein. But fuel-wise, it needs to get carbon dioxide. Then it needs sun to give it energy so that ha- it can actually form that bond, right? That's what it's getting its fuel from. All right. So if we think about, um, a classic, uh, plant produce, the plant that produces either a starch or a fruit, here's what happens. It inhales that carbon and then it starts packing it away. Now, in a root vegetable, what it does is it stores those things together. And if we store that thing and we grow a fruit at the bottom of it, we tend to call those things starches. All right? It's going to then take the carbon that is packed away in its root and send it up the tree.... and it's gonna actually do that by breaking it down into a smaller form of carbohydrate that we tend to often call things like sucrose and glucose. It'll ship that up the tree, it'll go out to the leaves, and it'll convert it into the fruit, and it's gonna eventually transform that stuff into smaller carbon things called fructose. And if we think about the fruit, uh, or the sugar in fruit, it's often in the form of fructose or sucrose or a combination and sometimes glucose. So, we have these smaller carbon, six carbon chains, generally in the ca- form of glucose, that are being made from this larger storage of, um, carbohydrates that we call, um, starch. Right? So it's packed in together. Your body does the exact same thing. So if it's a potato and it has a whole bunch of glucose packed away, we call that starch. If it's in your quadricep and we pack about, a whole bunch of glucose away, we now call it glycogen. If it's in your blood as that six carbon chain, we call it glucose. If it's in the tree and in the fruit, we call it fructose. Right? Those are different molecules. But that's effectively the same thing happens. So the biology, uh, or the chemistry (laughs) is almost identical, it just runs in the reverse order. And that's why, again, uh, tubers and potatoes and stuff tend to be starches and fruits tend to be glucose, fructose, and sucrose. So we have this wonderful circle of life. The plants can survive on just breathing in the CO₂ and then getting the energy from the sun. We don't have that ability, at least to my knowledge, to run through photosynthesis. So the only way we can get carbon into our system is to actually ingest carbon, which means we have to eat the starch, the fruit, the animal, some other form of stored carbon to get that into our system. We then pack that away. We put the carbohydrates, as you mentioned earlier, either in our liver, our blood, or in our muscles. We put the fat generally in adipose tissue. We'll put a little bit in muscle cells as intramuscular triglycerides, and then the protein we'll use as structure, right? We- we- w- to do different things. We don't like to use protein as material or fuel. It's- it's better used as structure. And what we have to do then is if all of a sudden we realize that storage is getting too much in our body, in other words, we're gaining too much weight, we have to figure out how to get the carbons out of our body. And that is metabolism, right? Any time we're trying to break a carbon bonds so that we can get energy to make ATP, that's gonna release the carbon out of our tissue into the blood. We have to bring in oxygen to bind that carbon molecule to make CO₂ so that we can exhale it and put it back into the atmosphere.
- AHAndrew Huberman
That's a beautiful description of the circle of life and energy utilization in the human body.
- 33:08 – 41:47
Exhalation Rates, Exercise & Fat Loss; Calories
- AHAndrew Huberman
I have to ask the question that I'm sure many people are wondering about, which is if indeed we exhale these carbons and as it relates to fat loss, that is the way that we lose fat if we're in a-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... sub-caloric state, for instance, has it ever been explored as to whether increasing the duration or intensity of exhales can accelerate fat loss? I mean, that's sort of the logical extension of what you described. And here, I'm actually interested, uh, equally in whether or not the answer is yes, as well as whether it could be no, because I could imagine if the answer is yes, well then there's some interesting protocols to emerge from that. But that if it's no, it will reveal to us some important bottlenecks about metabolism and energy utilization.
- AGAndy Galpin
You ever seen those magicians who, like, show up a- and, uh, they can tell your mom's name or something like that before you because they can sort of-
- AHAndrew Huberman
Oh, I-
- AGAndy Galpin
... lead you down a path?
- AHAndrew Huberman
Yeah. I mean, not to take us down a deep dive tangent, but I once went to the Magic Castle in Los Angeles, and I was one of the people called up front, and a, in- an incredible magician, uh, named, um, I think his name was Ozzy Mind or something, uh, I think that's right, had me write my name on a card in a Sharpie pen. I ripped up the card. I ripped it up. I put it in my pocket. And at the end of the 10 or 15-minute bout of him doing a bunch of other tricks, he asked me to look in my right shoe, and under my foot in my right shoe was that card intact.
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
And it was no longer in my pocket. And I swear on my life, I wasn't a, uh, collaborator with him.
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
And, uh, to this day, it still gives me chills because it- it... well, I- I don't know how, uh, magic.
- AGAndy Galpin
Yeah. Right. Magic. Well, the reason I say that is I've given that little spiel that I just gave you, uh, countless times in my classes. And I would say 99% of the time, as soon as I stop, the very first question is, "So can I just, like, do a bunch of exhales and lose fat?" Which is wonderful 'cause I was really hoping you would do that, and you rolled right into my trap. Right? You landed perfectly. So I- I look like a g- like a- a magician over here.
- AHAndrew Huberman
I feel like I should look in my right shoe right now. (laughs)
- AGAndy Galpin
(laughs)
- AHAndrew Huberman
No, I asked the question because it's the la- it's the logical extension of what you laid out, but I know biology to be, um, both, uh, diabolical-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... and cryptic, but also exquisite in the way that things are arranged-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... and you don't get something for nothing.
- AGAndy Galpin
There are no free passes in physiology.
- AHAndrew Huberman
Mm-hmm.
- AGAndy Galpin
That's the saying. No free passes. Um, the answer to your question is yes. 100% yes. In fact, that is the only way to go about it. You have two options. You can ingest less carbon or you can expel more carbon. People always say, "Calories in, calories out." It's really carbon in, carbon out. That- that's what a calorie is, right? Calories is the amount of energy we get per breaking a carbon bond. So it's really less in, les- more out. Less in is fairly obvious, whether that comes in any form. And by the way, this is exactly why the percentage of your intake coming from fats or carbohydrate is such, it doesn't really matter that much.If you look at fat loss, um, clinical trials, you guys may have covered this when Layne was in here, I'm sure. Like, this is something he talks about a lot. It doesn't matter. It's irrelevant, because it's not about that. There's nothing magic in those things. They are different, and they have different physiologic responses. Everything is different, right? No duh. But in general, it's just simply about carbon intake. Turns out fat has a lot more carbons per mole than carbohydrates do, so there's more calories per mole in there. So, if you... The physical amount of fat needs to come in as a smaller amount. The physical amount of carbohydrates needs to come in, will come in as a larger amount, but you can play any number of very high carb, low fat. What matters? Total calories, right? Again, it's not like the only thing that matters, but you know what I'm saying?
- AHAndrew Huberman
Sure.
- AGAndy Galpin
Some percentages in the way, you can go... Fat loss works fantastic high fat, low carbohydrate. Why? Why? Why do all these things work? Because it's not about that. It's about total intake of carbon, total exhale. So, absolutely can you lose fat by simply exhaling more. In fact, that is exactly what you did this morning.
- AHAndrew Huberman
When I hopped on the Airdyne bike for-
- AGAndy Galpin
When you did anything.
- AHAndrew Huberman
When-
- AGAndy Galpin
Right? The question is, can you think of a scenario in which you could have a bunch of increased rates of exhalation that helps in fat loss?
- AHAndrew Huberman
Sure. I can think of a lot of things that will stimulate increased rates of inh- exhalation.
- AGAndy Galpin
One thing could be simply going (exhales rapidly) . Right? And so the question is like, can I literally do some breath protocols where I force exhale and lose fat? And the answer is yes. But what happens? What happens if you do hyperventilation training?
- 41:47 – 47:03
Cardiovascular Adaptations, Cardiac Output & Maximum Heart Rate
- AHAndrew Huberman
these lines of exhaling carbons, uh, as the route for fat loss, it makes me wonder whether or not increasing lung capacity is possible. I'm guessing the answer is yes.
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
And whether or not increasing lung capacity is a good goal and route to enhancing fat loss. Essentially what I'm asking is if you can offload more CO2, aka carbons-
- AGAndy Galpin
Right.
- AHAndrew Huberman
... per exhale, are you a more efficient fat loss machine?
- AGAndy Galpin
It's a wonderful thought, and the answer would be no. Not something to worry about because-If you were to exhale more carbon than actually needed, now we're in a state of inefficiency. You're burning way more energy than needed to do your activity. The heart has a metric called cardiac output. Uh, this is, in science we abbreviate this as Q, for some odd reasons. It's either CO or Q. And cardiac output is heart rate multiplied by stroke volume. So it's how many beats per minute you're having as well as how much blood's coming out of it. So cardiac output is actually very specific to energy needs. If you try to work around that, it's just going to adjust itself. So what I mean by this is, if you were able to increase your stroke volumes, the amount of blood coming out per pump, you would automatically adjust to reduce your heart rate so that you keep cardiac output exact to energetic demands. So y- you're sort of pushing one end of the s- of the spectrum, but your body will pull the other one back to keep you at that exact same neutral level. So, um, if you look at, if you think about, like, cardiovascular adaptations to endurance training, a- any type of endurance training, a common thing people will understand is resting heart rate. And so what that number is, is just how many beats per minute you're having when you're sitting here doing nothing. A very positive adaptation is a lowering of that resting rate over time. Um, as general numbers, what you will hear is people will say things like, a, a normal resting heart rate is between 60 to 80 beats per minute. And, you know, if any of the things I've talked about, um, with the individuals I work with ... Uh, I don't work with anybody with disease, just, just to clarify that. I don't do anything with disease management, treatment, anything. It's always about people who are in a good spot who want to optimize or get to the next level, whether this is professional athletes trying to, to, to peak for physical performance or, uh, the folks in our rapid health optimization program that feel good. Again, it's not disease stuff and they want to feel incredible. One of the metrics we're going to pay attention to is this resting heart rate. So what, here's what happens. As you improve your endurance, your resting heart rate will go down. If I see somebody over 70 beats per minute, um, unless something's going on, you're not physically fit. Regardless of whether or not that is, quote unquote, "within the normative values," I want to see everybody sub 60 beats per minute, or close, right? Um, that's a, it's not a difficult thing to really get to for most people. So if you train a lot, regardless of how you train, intervals, steady state, doesn't matter, that resting heart rate will come down. But since energy demands at rest haven't really changed, cardiac output stays the same. So what happens is stroke volume goes up. So literally, like we trained your quadriceps on the leg extension machine to get stronger so you can produce more force per contraction, the heart will do the exact same thing. And so as you're able to get more of the blood out of your heart per pump, the heart realizes, "I don't need to pump as often." So that's the compensatory a- adaptation which is saying, "Hey, look, I don't need to beat 60 times a minute. I now need to beat 55 times a minute because I'm getting the same amount of blood out per pump, chill." And this is why your resting heart rate goes down, your resting stroke volume goes up, but your cardiac output is identical. So that's not a good metric of fitness. It's going to stay the same. Cardiac output will only adjust for energetic changes, right? Uh, energy requirements in the a- acute moment, right? How much do I need? Go. Which is going to be determined by ventilation, right? How much air am I bringing in and putting out? That's gonna determine cardiac output, and that's gonna determine where we're at. If you were to do, like, a submaximal exercise test when you are unfit to when you're fit, or when you're fit to where you're super fit, at submax you're gonna see the same thing. Cardiac output will be identical and you're like, "Damn, nothing happened." What you're not realizing is your heart rate at that same workload is now lower, and that's efficiency because your stroke volume is higher. Where it gets people tripped up is at max because you may not see a much of a change at max, um, because you won't really, you don't really see an increase in maximum heart rate with fitness. That's not a thing, right? So h- maximum heart rate is not a good proxy for fit or unfit or anything like that. Um, stroke volume will get limited eventually by filling capacity of your heart. Um, it has to have so much time to fill up with blood before it can contract again and squeeze the blood out. And when you have a heart rate of 200 beats per minute, that just doesn't leave much time to fill. And so it won't really push you past that. So, um, don't worry about trying to increase your maximal heart rate. That's not necessarily a good thing and it won't really change. But your cardiac output will because stroke volume will be higher.
- AHAndrew Huberman
But that doesn't necessarily mean that I should avoid training that gets me up toward maximal heart rate, correct?
- AGAndy Galpin
Oh, you should absolutely do it. Right.
- AHAndrew Huberman
That's what, that was my assumption.
- 47:03 – 47:55
AG1 (Athletic Greens)
- AHAndrew Huberman
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- 47:55 – 59:35
Excess Post-Exercise Consumption (EPOC); Exercise Intensity & Fat vs. Carbohydrate Energy Utilization
- AHAndrew Huberman
the special offer. Getting back to energy production and metabolism.
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
So we've got these different modes of moving energy, but making and breaking energy bonds in the body-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... moving energy into different tissues and out of different tissues, and indeed out of the body through exhalation. How do each of these different modes of energy utilization relate to different modes of movement and exercise?
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
In my mind, I'm starting to draw a bridge between, okay, when I walk for 60 minutes...Uh, you know, if I'm talking, I'm breathing a bit more. Maybe I'm burning a little more fat. (laughs) After all-
- AGAndy Galpin
Absolutely.
- AHAndrew Huberman
... speech is, is a, uh, modified exhale. Um, and-
- AGAndy Galpin
(laughs) Amazing.
- AHAndrew Huberman
... if I'm sprinting, um, breathing differently, and if I'm, um, you know, doing a 30-minute moderate... quote, unquote, "moderate" jog-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... breathing differently. So you've beautifully illustrated this bridge between energy production and utilization and carbon dioxide offload through exhalation. What are some of the specifics about energy utilization according to different modes of exercise? And if we could better define modes of exercise or-
- AGAndy Galpin
Yup.
- AHAndrew Huberman
... types of exercise that trigger specific adaptations, I think this is where the, the bridge will move from being a, a mere line to a, a real structure.
- AGAndy Galpin
Yeah, absolutely. I want to lay one more foundational piece, and then it's going to be much easier to understand the limitations that I put on some of these training protocols, as well as the lack of limitations. Okay? So it's really, really important. Um, the way I want to start this is we have this, this foundation now of, of carbon and, and basic energy production. That's not to say there's no difference. There is, and that difference is important. But maybe we can answer the question from earlier, which is actually something you asked me this morning when we were exercising. You're like, "Training fasted," right? "Does training fasted enhance fat loss?" And the logic is sound. If I don't have any fuel, then I should be burning more fat. Therefore, I should be losing more fat. It's sound. It's not true. It's this great idea. It's one of these classic things in science and exercise phylio- uh, physiology, where you're like, "Sounds good." Turns out it's not. It's actually a, a pretty gross misunderstanding of metabolism. So it's not to pick on that topic. I don't really care about that topic. But it is a... it's a common question. It also gives me an opportunity to just tell you more about metabolism. So here's what happens. You are breathing in O₂ and breathing out CO₂. However, the ratio to that is what we call the either RER, respiratory exchange ratio, or RQ, respiratory quotient. And I'm not gonna differentiate those two. They are not the same thing, but we're gonna skip past that for now. As you begin to increase exercise intensity, the percentage of O₂ to CO₂ rises in the favor of CO₂. So you start breathing out way more CO₂ than you are breathing in O₂, right? And so if we were to look at that number, you know, what's the relationship? It goes up. So at rest, most people have a, a... of a value that we would typically call something like 0.6. Okay? And that's, again, the relationship between O₂ and CO₂. Maybe 0.7. If you were to go for a walk, that increases slightly, because you're now expiring CO₂ at a higher rate. And so now you've moved up to, say, 0.8 or something like that. One of the ways that we mark somebody of achieving an actual VO₂ max on a test is if that value exceeds 1.1. Now, any of you who are paying attention are thinking, "Well, wait a minute. How the hell can a ratio between two things ever get past one?" Well, that's because you're getting to a place where you're actually offloading more CO₂ than is actually necessary. And this is what actually causes and explains, uh, a thing that people like to call EPOC, which is excess exercise post-oxygen consumption. This is another way to think about it. The only reason you're breathing is to bring in oxygen and offload CO₂, right? If I'm no longer exercising, why am I still breathing? In other words, once you stop the demand or the need for ex- for energy, you should stop ventilating, but you don't, right? That's because in the case of low-intensity exercise, the second you stop, (exhales) you're right back down to resping ventilation. No problem, because you were able to match the need for energy with the offload of waste one-to-one during that exercise. When you start creeping up the intensity, you can't do that. So you have to basically start stealing a little bit of fuel here. So even though you're done exercising, you're still ventilating because you have to pay that back. And pay that back, by that I specifically mean you have to bring in oxygen, 'cause you have a whole bunch of waste that's been accumulating in your tissue that you've got to deal with, and I- I'll walk you through what that waste is. It's a particular molecule that a lot of people have heard of, but grossly misunderstand. So you gotta be able to handle that. So the reason that you sit there and go (panting) and continue to ventilate is because you're now trying to pay back that excess post-exercise oxygen debt. That's that oxygen debt we're specifically talking about. All right, so that being said, as we start cruising up, that RQ starts going up, up, up, up, up, up, up, and if we get to one, you're 1.0, you're, you're in a... like, you're hurting. You're in a, in a pretty good spot. All right.
- AHAndrew Huberman
I like that. "You're hurting. You're in a pretty good spot."
- AGAndy Galpin
Yeah. (laughs)
- AHAndrew Huberman
There's a, a window into Dr. Andy Galpin's mind. Uh-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... now you really want to be a subject in his, uh, his laboratory studies. (laughs)
- AGAndy Galpin
Sure.
- AHAndrew Huberman
Masochists swarm to Andy's lab.
- AGAndy Galpin
Absolutely. All right. So the idea that I will lose more fat by being in an exercise situation that is burning more fat, it seems to make sense, but it's a massive failure to understand the metabolism. It's the exact same explanation to why exercising fasted doesn't matter. So the exercising fasted issue under normal circumstances is irrelevant, because you have plenty of fuel in the system, even when you haven't eaten breakfast that morning. Now, if you're talking, like, extended fasting over multiple days, this is a different scenario. If muscle glycogen, liver glycogen, and blood glucose are at sufficient levels, then you absolutely have enough energy to perform almost any type of exercise that most people are doing. You know, maybe if you're Rob and you're at mile 20 today, it's a different story, but the vast majority of us have plenty of fuel sitting around, so we're not going to burn more into fat, um, just because we didn't eat breakfast that morning. So that just doesn't make energetic sense. We have a lot of backup supplies. You're never out.The trick here is this. Is, there's a, there's a concept here we call crossover concept. So, as we are starting to move up exercise intensity, we start burning a higher percentage of our fuel from carbohydrates, and a lower percentage of our fuel coming from fat. I'm sleeping. That's the highest percentage of your fuel that will be coming from fat of any activity you could ever do. So, if the theory that I'm gonna stay at a lower intensity to burn more fat was true, the optimal fat burning strategy would then be to sleep. Like, that doesn't make sense. Of course it doesn't. So, why would then going at a slightly elevated rate somehow all of a sudden magically make you lose fat? It doesn't actually make sense. When you think about it that way, you're like, "Oh, yeah. There's no way." So, it's a percentage trick. It's the difference between absolute and relative. This is what this confusion is. So, yes, as you start doing lower intensity to exercise, whether you're faster now or not, it- it's irrelevant. But lower intensity to exercise, a greater percentage of your fuel is coming from fat. However, your total fuel expenditure is very low, so that whole total carbon balance is not really being shifted much. As you start exercising at a very high intensity, you actually start getting a higher percentage of your fuel from carbohydrate and a lower percentage from fat. In fact, at rest, about the highest you can get in most people is about 60% of your fuel from fat. As you're sleeping, you might be 70%. But you'll never be in a position ever, no matter what sort of thing you've heard on the internet, you'll never be in a situation where fat is your only fuel source. The highest I've probably ever seen is, like, 70%. Um, you should probably be at about that. Th- that's a kind of a good number to think, um, honestly. But people will understand a little bit about metabo- metabolism to be dangerous, but not enough. We'll, we'll throw out these terms like fat-adapted. And fat-adapted is a real thing, but it is a massive misunderstanding oftentimes, right? It is this idea thinking, like, I can get into a spot where I'm maximizing fat burning. Maximizing fat burning, and maximizing fat for exercise, and maximizing fat loss over time are not the same thing at all, right? That's the confusion. So, if you enhance fat oxidation in exercise, that does not enhance fat loss per se, right? So, this is the lot of the confusion that's happening, right? So, as we start moving up, we can never get in a position where we're using fat only as a fuel. Again, at best, you're at 70% fat, 30% carbohydrate, for a lot of reasons we probably just don't have time to get into today. However, the opposite is possible. When you get into true high intensity exercise, you'll be basically 100% carbohydrate and 0% fat, all right? That is- is very possible. That, in fact, is 1.0. That's at our q- ... 1.1 is actually because your ventilation got so high you actually exceeded that number, even though you're at 100% carbohydrate. This is what people came up with the idea then is, like, "Well, I don't want to burn carbs. I want to lose fat." So, my response to that is always like, "Okay, great. So, it makes sense. Burning fat, losing fat. Burning carbs is losing what then? Like, you think your liver shrunk?" Like, well, wait a minute. What did you lose then? Where did it come from? It's all coming as carbon. Don't worry about where it came from for your fuel. It just has to come out as carbon, right? There are differences in exercise efficiency for performance with our professional athletes, of course. But if the only goal here is fat loss, it doesn't matter where you get it from. The last bridge we have to connect here is like, well, wait a minute. If I only burned carbohydrate, how did I actually lose that fat? There was- there was that love handle sitting on the side of me. How did that come out of me if I never burned that from my fuel? And what you're failing to understand is there's a balance game that happens here. So, if you were to do a bunch of high intensity exercise training and you burned only muscle glycogen and blood glucose and maybe even you did it for so long you burned some liver glycogen, the body understands that it has expelled a lot of energy from that side of the equation. It's going to do a couple of things. Now, it's very difficult to go through this fancy situation where you convert carbohydrates into fat and back and forth. Like, that's actually, like, fairly hard. What's easier to do is something you said earlier, is actually just bias energetics to a different fuel source. So, in that scenario where you're down really low in your carbohyda- carbohydrate stores, any carbohydrates you bring in are going to go to storage. And since your net energy expenditure is something that your body regulates a lot, any fat that you then bring in is going to be utilized as a fuel source because it knows it doesn't need it anymore. That is in excess. So, that's how you actually use fat as a fuel, because you've burned down carbohydrate storages.
- 59:35 – 1:08:01
Tool: Training for Fat Loss, Carbohydrate Stores, Liver Glycogen & Fatigue
- AGAndy Galpin
- AHAndrew Huberman
As I'm hearing this, uh, a couple of things come to mind. First of all, thank you for that incredibly important description of what is otherwise a very confusing landscape for most people. One of the key points I took away, and I just wanna say from the outset, this is not exhaustive by any stretch, is that burning fat does not equal losing fat from the body.
- AGAndy Galpin
Correct.
- AHAndrew Huberman
And then burning fat has to be divided into burning of body fat stores, and we need to distinguish that from burning of dietary fat that is brought in.
- AGAndy Galpin
Correct.
- AHAndrew Huberman
Oftentimes people don't disambiguate those, right?
- AGAndy Galpin
Correct.
- AHAndrew Huberman
And I'm also understanding that reducing one's body carbohydrate stores, muscle glycogen, liver glycogen, et cetera, occurs during high intensity exercise.
- AGAndy Galpin
Yep.
- AHAndrew Huberman
As well as other ways, but that is one very efficient way to tap into those stores. Which makes me wonder, again, this is one of these things. Does it lead to a protocol? Makes me wonder whether or not doing high intensity, let's say, weight training for 45 to 60 minutes, 75 minutes-
- AGAndy Galpin
Sure.
- AHAndrew Huberman
... of strength training, power training, hypertrophy training, which we've covered in an episode about those topics, and then-... doing some steady state cardiovascular exercise. Is there any benefit to that arrangement that would, quote-unquote, "enhance body fat loss from the body," to be very specific now-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... because unlike the idea that training fasted would shift the bias towards fat loss, which it doesn't, you've told us, under those conditions, muscle glycogen and maybe even liver glycogen is going to be depleted. Put simply, can I enhance body fat loss by doing some cardio after a bout of weight training?
- AGAndy Galpin
If you equate for total energy expenditure, it won't matter. Now, th- you did bring up a very important point that I want to clarify. If you look at the exercise modalities that we laid out in our previous, uh, conversations, we talked about nine different adaptations. One was skill, and then speed, power, strength, hypertrophy, muscular endurance, anaerobic capacity, aerobic capacity, and long duration endurance. Now, speed, power, and skill development have almost no benefit for fat loss, because remember, those are low weight, a lot of rest, and low volume. They're not really, really going to be helpful. You can make a little bit of a case for strength, a little bit, but the total energy expenditure for strength training, even if it's an hour, if it's truly strength training, it's fairly low-
- AHAndrew Huberman
Because the repetitions-
- AGAndy Galpin
... to be honest.
- AHAndrew Huberman
... are in the one to three range.
- AGAndy Galpin
That's exactly, it's not enough for total work. So if you're trying to develop a protocol that sort of optimizes fat loss, what you want to do, you were close, and my opinion is do a combination of something in the hypertrophy/muscular endurance strength training realm.
- AHAndrew Huberman
Okay, so, um, six to 30 repetitions-
- AGAndy Galpin
Something like that.
- AHAndrew Huberman
... of resistance training.
- AGAndy Galpin
Great.
- AHAndrew Huberman
Deplete muscle glycogen, maybe even a bit of liver glycogen.
- AGAndy Galpin
Maybe a little bit, depending on if you're doing it for a long time, but probably not a noticeable amount.
- AHAndrew Huberman
Okay, so an hour of, of, uh, hypertrophy type training.
- AGAndy Galpin
I- if you're training hard with low rest intervals and you really did an hour, you would for sure get there-
- AHAndrew Huberman
Which is-
- AGAndy Galpin
... but most people don't, because you take breaks.
- AHAndrew Huberman
... the reason why I crave large bowls of oatmeal and rice after I do weight training?
- 1:08:01 – 1:16:07
Metabolic Flexibility, Carbohydrates & Fat; Exercise & Flexible Fuel Utilization
- AGAndy Galpin
- AHAndrew Huberman
I want to make sure I understand a concept that you referred to earlier correctly, because I have a feeling that I don't, and that's this issue of how the body accesses body fat stores-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... when in a subcaloric state and I'm doing mainly glycogen burning exercise.
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
What I heard you say, and please correct me where I'm undoubtedly wrong, what I heard you say was that, okay, I go into the gym and I start lifting weights. I'm burning muscle glycogen, mostly local to the muscles that I'm using, and then I start pulling glycogen from the bloodstream. Maybe there's some body fat stores that are mobilized, probably not dipping into my liver glycogen. Okay, I complete the workout. Maybe I even hop on the Airdyne bike and do a little sprint.
- AGAndy Galpin
Yep.
- AHAndrew Huberman
Maybe I go for a jog. Maybe, um, I eat immediately afterward, maybe I don't eat for a few hours afterwards, but across the day, I ingest fewer calories than I burn. Is it the case that body fat is mobilized in order to replace the glycogen that my subcaloric intake was insufficient to provide?
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
In other words, because I didn't eat enough to fill the glycogen stores, am I using body fat converted into glycogen to fill those stores?
- AGAndy Galpin
Right.
- AHAndrew Huberman
And if so, is that a case where I'm no longer exhaling carbons in order to burn body fat, but rather I'm repurposing body fat into muscle? Have I turned fat into muscle in that case?
- AGAndy Galpin
Yeah. I'm, I'm really glad, um, you asked this because I did a very poor job on that last point talking about it earlier, um, I'm realizing playing back in my head, because there's, there's so many really good questions. You cannot turn fat into muscle.
- AHAndrew Huberman
Can you turn muscle into fat?
- AGAndy Galpin
No.
- AHAndrew Huberman
I'm so glad you said that because when I was in college-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... our... Oh, I don't want to out that person. The physiology teacher seemed to think still at that point that one could, um, lift weights, get muscular, but then it would eventually turn into body fat. That, that I- that myth has, I think, largely been dispelled. Um-
- AGAndy Galpin
I heard that so many times, uh, as a kid. I heard it so many times in college. I heard it so- I hear it so many times in our undergraduate students from other faculty and such. So, um, no. Like that, they are not the same structures. They are very different. Um, let me, let me take a shot at answering this better. You were really, really, really close. So yeah, if you were to do that type of exercise where you've burned a lot of muscle glycogen, how is it I'm losing stored fat, right? That's really the crux of the question. And it doesn't even actually matter if you then went ahead and ingested extra, uh, carbohydrates or fat post-exercise. Um, that's not really a thing. You hit on a couple of key things. Number one, this is all under the assumption that total caloric intake is still low, right? You have to have-
- AHAndrew Huberman
Below total need.
- AGAndy Galpin
Below total need.
- AHAndrew Huberman
For... Okay.
- AGAndy Galpin
Right. I also want to flag calories in, calories out is not the only thing that matters. This is a very complex thing. Calories in is incredibly complicated. Calories out is even more complicated, okay? So we just, w- maybe another series we can spend on that alone. All right? So don't, don't go nuts about that. You have to be hypocaloric one way or the other. If you burn a bunch of muscle glycogen and you are hypercaloric, you're still going to add fat. If you burn a bunch of muscle glycogen and you're hypocaloric, you're going to lose fat, right? Think about it this way. You are in a negative calorie state. Where are those calories going to come from? Are you going to reduce your muscle glycogen storages permanently?
- AHAndrew Huberman
No.
- AGAndy Galpin
No. Are you going to reduce your glycogen storage in your liver?
- AHAndrew Huberman
No.
- AGAndy Galpin
You want to reduce blood glucose?
- AHAndrew Huberman
No.
- AGAndy Galpin
No way, right? So where is that extra energy coming from? It's coming from your stored fat. It is your backup reserve energy system. Um, the way that I want to flag this here is people tend to think about it as like carbohydrates versus fat. That's not... It's more like a chain, more like a bicycle where there's a front gear and a back gear. You turn one gear, it turns the other one. These are complementary systems. They are not and/or systems, right? You're, you're turning one... And when we go through carbohydrate metabolism, uh, maybe here in a second, you'll understand why you have to have an anaerobic and an aerobic component to that. There is absolutely no way to complete carbohydrate metabolism without oxygen. That has to happen. The only way to engage in fat metabolism is aerobic and oxygen. There's no anaerobic component to it. There's a fundamental difference there.So the-- your carbohydrates are meant to be incredibly flexible. It is the primary fuel source for a reason. Your fat is not meant to be flexible. It is meant to be unlimited. That's the basic point. So you want flexibility over here and then unlimited capacity over there. Now I'm safeguarded against any energetic need, okay? I need to run up a hill for safety. Cool, carbohydrates are there. I need to then run for 17 hours. Cool, fat is there. We want both of these systems, um, you want to be able to have great energy throughout the day. You want a slow drip coming from fat. You don't want up and down, up and down, feel great, up and down. Awesome. You want to be able to think very quickly and get hyperfocused. Boom, carbohydrates ramp right up, right? Get it into the brain, get thinking better, get thinking clearly fast. So we want all these, not just for exercise purposes, for, but for activities of daily living, we want an optimal system here. And when people use the terms like fat adapted, they're generally hijacking that and they're thinking ma- th- it used to be a thing we said all the time in, like, all of my undergraduate classes for years, and that idea of metabolic flexibility is using optimal fuel sources in optimal types, not maximizing fat usage. They- people have co-opted that term of metabolic flexibility to be like, "Oh, yeah, yeah, therefore learn how to maximize fat burning." That's not what that term means. That term means maximizing your ability to use whatever fuel is optimal in that time. Now, I'll grant you, most people aren't fantastic at using fat as a fuel source relative to the other direction, but nonetheless, the- the- the gold standard here should be maximizing both. All right, finally answering your question, if I were to, to burn a bunch of muscle glycogen, how am I losing that fat? Well, the fuel you're ingesting in that hypocaloric state is going to say, "Hey, look. We have a lot of muscle glycogen we have to replenish. So any carbohydrate that comes in needs to be biased towards storage. It's gotta go into those tissue. Any fat that comes in or doesn't even come in, but any fat that we're using for fuel needs to be utilized for activity." And that's where the caloric expenditure from fat comes in. So you're basically saying your general physiology, s- the energy for that starts coming from fat, and the energy that's coming in from carbohydrate needs to be simply stored. And so what you see is your respiratory quotient changes, right? The RER is going, is going off. And so in the exercise moment, it shot way up for carbohydrates and shot way down for fat. As a compensatory response, it goes the other direction, because your body's saying, "We are low on carbohydrates. Don't use them for fuel unless we absolutely have to," right? So use them for storage. Get our fuel from the fat side of the equation. And so what you're generally going to say is like, "Oh, I'm burning more fat just sitting around" after things like that. And that's not even taking into the equation the EPOC part, which is, like, it- it's not actually as- as large as people think it is. It's fairly small, but it is, i- it adds up sort of over time, so does that explain a little bit better about how you lose fat when you actually only burn carbs for exercise?
- AHAndrew Huberman
Y- you explained it beautifully.
- 1:16:07 – 1:19:40
Muscle & Basal Metabolic Rate
- AHAndrew Huberman
You talked about EPOC, the post-exercise oxygen consumption-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... not being that significant in terms-
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
... of energy utilization. Even though today we're talking about endurance and different forms of endurance, I do have to ask whether or not people consider the elevation in basal metabolism that occurs when there's more muscle around.
- AGAndy Galpin
Yeah.
- AHAndrew Huberman
Because muscle is such a metabolically demanding tissue, um, you know, if, is there a straightforward-ish equation, you know, if one adds one pound of, of-
- AGAndy Galpin
Mm-hmm.
- AHAndrew Huberman
... lean muscle tissue to their body, even if it's distributed across m- multiple muscle groups, does that equate to, uh, a caloric need of X number of calories per day?
- AGAndy Galpin
Yep.
- AHAndrew Huberman
And is that because of the muscle protein synthesis needs of that muscle or its glycogen storage needs or both?
- AGAndy Galpin
If you don't have enough muscle, you start to have problems with fat loss. It's- it's a difficult challenge. If you have enough muscle, uh, and you're just trying to get extremely large, if- if your FFMI is 24 and you're 15% body fat, adding more muscle's not really gonna play a lot in the equation, and here's why. Muscle is more metabolically active at rest than fat, but fat is not inert, so fat is still going to burn a- a small number of calories. Muscle burns more, but it's not nearly what people think it is. I'm a muscle guy. I'm a muscle physiologist. I would love to get people to have more muscle for any excuse I can. It's not honest to say that, though. Um, you're talking about when I was in undergraduate, we would say numbers like 50 kcals per day per pound is what you can look at, right? So if you put on a- a pound of muscle spread across the body, your basal metabolic rate would go up by around 50 calories, um, per day. I think that number is grossly exaggerated. It's probably a 10th of that, six to 10 calories maybe. Um, it's- it's hard to know exactly what that number is, but the more recent estimates are- are something like that. So now on one hand you could say, "Oh my gosh, that is not even meaningful." On the other hand, you could say, "That's super meaningful." It just depends on time domain you want to put that out, right? So if you were to put on five pounds of muscle and your basal metabolic rate went up 30 or 40 calories a day, well, over the course of 1,000 days, like, that actually adds up. So you- you could slice this any way you want. Um, now maybe that number is somewhere in between. I don't really know. It's not a field I pay that much attention to, candidly, because it's- it's not a metric, kind of like EPOC, um, where it's like we used to really harp on it and now it's sort of like, well, maybe we exaggerated that, like, honestly just a bit. But to me it doesn't change the equation much because if you don't have enough muscle, as I described, there are other consequences that are gonna make fat loss hard. And so you need to have sufficient muscle.If the additional caloric expenditure is the carrot, great. If it's something else, I don't really care. Um, there's just enough evidence that you need to have it. Or I should say, there's enough evidence that it will really help you in your path. Um, maybe a few calories here or there is not really the thing. E- especially if you understand a normal food item, anything you pick is going to be probably a couple of hundred calories. One bad food choice a day will out-kick almost any amount of coverage you got on a- adding muscle mass to you. So like, you're, you're really stepping over a dollar to pick up a dime if you're worried about how many calories you're getting from adding muscle. Um, fat loss is gonna be about regulating that carbon intake above and beyond anything else.
- 1:19:40 – 1:20:43
InsideTracker
- AGAndy Galpin
Episode duration: 3:48:52
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