 Welcome to the Dr. Gundry podcast. Well, by now, you know I'm pretty obsessed with energy because of my new book, The Energy Paradox. I just published the brand new book. Well, on today's episode, my guests and I are going to dive really deep into our energy production. And we're going to do it by taking a close look at one of the last true hunter-gatherer societies on Earth, the Hadzah. I'm joined today by Herman Ponzer. Dr. Ponzer is an associate professor of anthropology at Duke University and just wrote a brand new book called Burn. New research blows the lid off of how we really burn calories, lose weight, and stay healthy. Now in today's episode, he and I are going to reveal the truth about your metabolism, explain why exercising won't necessarily lead to more fat burning. Oh, no! And why the 2,000 calorie a day diet might be all wrong. And just as an aside, off camera, we learned that, first of all, you may all know that Yale, my major, was in human evolutionary biology, which is what Dr. Ponzer studies. And my mentor, Dr. David Pilbein, was on his PhD committee at Harvard to look at his thesis. So, boy, do we go back a long way together. So, Dr. Ponzer, I'm so excited to have you on the podcast today. Thanks for having me. Great to be here. All right. So, yeah, this is going to be fun. And everybody pay attention because what Dr. Ponzer says may shake you up a little bit. Okay, so you're right in the book that metabolism is the unseen foundation underlying everything, slowly shifting and shaping our lives. What do you mean by that? Why is metabolism so important? Well, that's right. I can't think of any single measure you'd take of an organism that would tell you more about it and how it evolved and how its body works than how it spent its energy. Life takes energy. From an evolutionary point of view, which I'm sure you can appreciate, life is a game of turning energy into kids. That's kind of all evolution cares about. Amen. That's correct. So, your immune system, your nervous system, reproductive system, all the housekeeping stuff your body does to stay alive, all of it takes energy. And I think one of the reasons I wrote this book is I think energy expenditure gets talked about in terms of diet and exercise, and that's kind of it. But of course, it's so much more than that. And so, kind of taking the lid off of that and showing people how that all works was one of the motivations for doing the book. So, what do people get wrong about metabolism? Well, you know, I think the way that people are taught to think about your metabolism is in a really simplistic kind of, you know, the analogy is sort of like a car engine. You know, well, you're in control and you can rev it up faster or take your foot off the gas, and if you put more fuel in than you burn off, you get overweight. Well, that last part's pretty true. If you eat more than you burn, you're going to gain weight. But the other part's really wrong. You know, we're not a simple energy burning engine. We're a product of evolution. And so, you know, our bodies are much more sophisticated and dynamic and complex in the way that they take in energy and burn it off. If we don't understand those complexities, I think we're missing almost the entire picture here. So, that's what I think they get wrong is I think we're taught that our bodies are simple and they're not simple. So, you mean, I know you talk a lot about this in the book, but why won't more exercise lead to more fat burning? I mean, everybody knows that. Come on. Yeah, I know, I know. And, you know, I thought so too. And in fact, I was a young assistant professor at Wash U at the time, and I actually put together a grant to the National Science Foundation to go and show just exactly that that people who had really physically active lifestyles, these hunter-gather folks that I was going to go work with in northern Tanzania, would be burning tons more calories than you and me or everybody else kind of sitting here in our sedentary lives here in the west. And what I found instead was that when we went there, we actually measured calories burned per day in this hunting and gathering society, you know, incredibly physically active. But their total calories burned per day was no different than people in the U.S. and Europe. And so that put me on a whole, you know, that really changed my research focus because, wow, now we have this really big mystery to kind of understand. And the more you track it down, the more work we've done since and other labs too, it just shows that people who are more and more active, their bodies don't necessarily burn more calories. Instead, your body is making these adjustments to kind of keep total calories burned the same, regardless of your lifestyle, and instead sort of shift the way the energy is spent. So it seems that energy exercise doesn't change the way, sorry, it doesn't change how many calories you spend, it changes the way that those calories are spent. Yeah, your study, actually I talk about in the energy paradox, and maybe as we go along in this, we can talk about why I think the desk worker burns the same amount of calories as the hunter-gatherers in Tanzania. And you're right, that's true. You know, in my book, The Longevity Paradox, I talk a lot about the connection between longevity and metabolism. And I know you do too. So give me your thoughts on, are those two connected? Well, yeah, that's one of these million-dollar questions in biology. And there's a lot of tantalizing evidence out there and people are connecting those dots in different ways. The way that it seems to me, and I think a sort of evolutionary biology perspective would be, is that the pace of life, the speed at which you grow up, reproduce, grow old, if we look across species, from mouse to elephant to a wide range of species there, seems really nicely correlated. Animals that burn energy faster live shorter lives, they kind of burn up faster. Now, that's interesting because when we look within a species, it doesn't seem to be quite so simple. You know, going exercising and you burn more calories, maybe well, you exercise doesn't seem to be bad for you. In fact, it seems to be really good for you. So there's an interesting nuance there. But in general, metabolism seems to set your pace of life. Well, yeah, I want to stay on that subject for a second. When I was at the NIH as a clinical fellow, one of my mentors, Andrew G. Morrow, heart surgeon, used to ascribe to the theory that we only have so many heart beats in our lifetime. And you can use them up fast, or you can use them up slow. And he was a rather large individual, and so he believed in using his heart beats slowly. Long story short, it didn't work out well for him. That theory always kind of comes around. Can you elaborate on that? Well, so it does seem to be the case. This is an idea that's at least a century old. In fact, you can see even people say Aristotle had this idea too that animals seem to sort of burn up faster if they're smaller. Anyway, so it's an old idea that's out there. Now, like I said, it's true that there is this pattern that animals that burn energy faster, because small animals, for example, burn their energy faster than per gram, per pound, than large animals do. And that seems to track with how fast they burn calories. Primates as a group, for example, humans, monkeys, apes, we burn our calories really slowly compared to other mammals. And that seems to be related to in a causal way to the fact that we also grow really slowly. So humans might live 70 or 80 years, maybe longer, but in animal size, you'd expect to actually have a shorter life. So metabolism is shaping the overall picture here. Now, when you get to within a species, it gets more complicated, because the reason probably that metabolism has this relationship to longevity is at least in part due to things like oxidative stress, other byproducts of metabolism that kind of wear you out and kind of eventually break you down. Your body has defenses against those byproducts. And so you can imagine a species would be better or worse at handling that kind of oxidative stress and that kind of thing that would come along with metabolism. See, you're going to have variation there that's not going to be just about metabolic rate. And also, things like exercise, things like aspects of your diet, which I know you've talked about, have big effects on how you handle that oxidative stress, how you handle that metabolic damage. And so there's going to be a lot of nuance into that. It's not going to be as simple as someone with a faster metabolic rate should have a shorter life than somebody with a slower metabolic rate. And yet, again, it's the sort of the big pattern fits, and when you get to more detailed looks at it, it kind of gets more complicated. So what do you mean in the book when you say that something is more costly in terms of energy than something else? Say walking versus climbing. Right, so we can talk about your energy budget, the way you bring calories in, the way you burn them off. We can think about that in the same way that we think about analogous to any kind of budget, a monetary budget. And so we talked about the cost of things in biology in terms of calories per hour, calories per mile, right? So running costs about twice as many calories per mile, about 100 calories a mile for most folks as walking. Walking costs about 50 calories per mile. So are you telling the runners that you're much better off walking if efficiency? No, I think all of that metabolic work you do to exercise is really good for you. And that's not news. I think we know how good exercise is for you. But I think what is new in this book is that the reason that all that energy spent on exercise seems to be so good for you is, again, it's that adjustment that it causes your body to make. So when you go out and exercise and you kind of adopt an active lifestyle, you're not burning more calories per day, necessarily. But your body is making adjustments in the other things it does to make room for that bigger exercise budget, that bigger exercise cost. And so if you go running, yeah, you're spending more calories than you would if you were to walk or, for that matter, just to sit on your couch. But those extra calories spent running are calories that you're not spending on inflammation, on stress reactivity, and other things that your body otherwise will do if you don't spend the calories in a good way, it might spend it in a bad way. And so those exercises are good even if they're burning more calories. And I think it's one of the reasons exercise is so good for you. Well, I think that's a really important point that you make. And I spent a lot of time talking about this in the energy paradox. And that is the desk worker maybe burning up the same amount of energy as the hunter-gatherer, which on the surface seems absolutely impossible, right? But at the same time, we're putting our energy into producing inflammation. And as you and I both know, producing inflammation is incredibly energy costly. And again, I used your paper to say, well, yes, it's true that the desk worker and the hadza have the same energy expenditure, even though that hunter-gatherer is walking five, eight miles a day and sitting on his haunches another five hours a day. But the desk worker is just burning up with inflammation, often that's unseen. And that costs energy. What say you? Absolutely. You're in the immune response, which is your inflammation is part of that. You need some of it, right? When you get a cut or you get a cold or whatever, you need that immune response. But it seems to be really, really tuned up too high, too responsive, right? And it's like you need the fire department, but you don't want them at your house all the time, you know? You only want them there when there's a fire. And by taking exercise out of our lives, our bodies have spent the energy elsewhere, and it's on this sort of emergency response, only the emergency response is chronic, and now you have some real trouble. No, you're absolutely right. Okay, so what about our brains? You know, I write in the Energy Paradox that our brains are real energy hogs. That's right. And you know, it only occupies a little bit of our body, but it's a tremendous energy hog, right? It is. It's shocking how much you use. I mean, 300 calories a day by most estimates. You know, that's the equivalent of running for three miles or 5K. Your brain runs a 5K every day, and it's really expensive. You know, it's a really expensive organ. We call them expensive organs in biology, and we see sort of evolutionary trends in these expensive organs, because it's a big investment for an organism to have a big brain like we do. Your liver is expensive, too. You know, your kidneys are expensive, too, but that brain, humans are remarkable for having big brains. And you know, it's interesting why wouldn't other animals evolve big brains? It seems like such a good idea. Because again, metabolism is everything, right? And if you spend that energy on a big brain and not on reproduction, then evolution says, that's not favored. So you know, it's part of our strategy, but it's an expensive part of our strategy. So what you're saying is our big brains prevent us from reproducing like rabbits? Well, maybe that's right. Or I would say, you know, the only reason that evolution favors a big brain is because it helps you in the end be better at reproduction. And you know, this hunting and gathering strategy, we're all hunters and gatherers for the past two million years. And it was such an effective strategy, but it also has to be a very smart strategy, right? Because think about, you need to understand every plant on the landscape, every animal and how it works. You need to be able to hunt. And it's a really hard way to make a living. And so it's not surprising, I suppose, that it really only happened once, that this really sort of strange, clever way of getting by on your smarts. You know, it's such a hard thing to do. Of course, we feel like, you know, it's the obvious thing to do, but it's not obvious at all. No, not at all. Let's talk more about your work in Tanzania. What was the most surprising thing you learned while tracking and measuring the Hadza? Well, it has to, the one big surprise has to be that, you know, even though they're so physically active, I think if you're a step counter out there, the men are getting about 19,000 steps a day. The women are getting about 12 or 13,000 steps a day. So an incredible amount of walking, you know, it's just hard. It's a hard life. And the fact that they can do that and still have the same calorie, you know, burn the same calories a day as you and me is just, was just shocking. But you know, there are other things that were really fun too. You know, we are often told, oh, the hunter-gatherer diet was all meat. You know, that's a common thing you hear these days. Now the Hadza are out there, 10 or 15% of their diet or more is honey. You know, the men, when they're done hunting, they go out and get honey. The women are always bringing home these big starchy tubers and berries and stuff. So, you know, it's a really flexible diet. It's really, you know, day to day, season to season, it's super flexible. So the idea that there's sort of just one way to be a hunter-gatherer, you realize, no, you know. And I think it's also just adaptable and flexible in terms of just how they see life. And I think there's a lot of lessons there to be learned about, you know, getting out of your sort of mindset of it, you have to do things one particular way and giving yourself a break a little bit and being more flexible and finding an approach that works for you. I thought it's interesting that even they set a large portion of the day. But they sit on their haunches. And I've been to Africa a lot on mission work during surgery and digging wells for charity water. And it's interesting, most people, there aren't chairs that anybody sits on. They are on their haunches. And I've done this on myself and looked at my patients. It actually takes a lot of energy to sit on your haunches. It takes big muscle groups. Yeah. And especially if you don't do it regularly, right? I think I try, you know, the kind of typical afternoon, you know, you go out and maybe go out on a foray with a man or woman. And, you know, we're anthropologists. So we're interested in their daily lives. And so we're out there with them all day. But often you're home in the afternoon around, sitting around a campfire. And, you know, they just sort of squat down. And like you say, on their haunches and they're very comfortable. And you try to, I try to do it and I haven't been doing that my whole life. And I've lost that flexibility. So I look like, you know, I'm all discombobulated trying to do it. So, you know, if you don't do it your whole life, I think it's especially hard. But even for them, you know, we've done this measurement. Their muscles are core muscles and their big muscles are active, right? So that's one of the reasons, even though they might sit as much as we do, it doesn't seem to be as bad for them because they're staying a little bit active. And that little bit of activity seems to be really important for keeping them healthy. Yeah, no, I think you're absolutely right. And, you know, I took that message in my book, The Energy Paradox, to have people do what I call exercise snacking, where you just five minutes every few hours do something like sit on your haunches or try to for five minutes. And you're right. It's actually challenging if you haven't done it your whole life. Yeah, that's right. And I think, you know, that's a great idea. And it's a very hard idea that you don't sort of make exercise this one hour a day thing that you do, you know, in a kind of... If that works for you, that's great. But for a lot of us, I think it's easier to think about it just as sort of something that we weave into our daily lives, right? And accumulate over the course of a day rather than, oh, I'm going to do that from seven to eight tonight or from five to six in the morning. That's great too. But weaving it in throughout your day, I think, is really a smart way to try to get as much activity as we're involved to get. So I want to... Since you've spent time with them, as you probably know, I'm sure you know, they have a very different gut microbiome than us in the West. They have a very diverse microbiome. It changes with the season. And as a microbiome researcher, I think diversity in the microbiome is one of the keys to great health. And I know in your book, you say a calorie is a calorie. But I want to challenge you, I think, depending on your microbiome, that a calorie may not be a calorie. It depends on what your microbiome takes for themselves or what your microbiome harvests and gives to you. All right, what say you, Professor? Well, that's a really interesting idea. And it's worth looking into. We don't have... I know the studies on what you'd call that metabolizable energy or the utility of metabolizable energy. I'm not sure that you have the data yet to know how different foods vary like that. What we can say, and I think you're right about this absolutely, some people, if you have a gut microbiome that's healthy and diverse, you're going to be able to handle fiber a lot better, for example. And fiber gets turned into short chain fatty acids, which your body can use for energy. So in that case, a calorie of fiber, which might pass through and be unused by somebody, might be able to get used by somebody else. So point taken, and I think you're right about that. No argument there. I think the calorie is a calorie thing. As somebody who studies energy expenditure, what I get upset by, or I know what I'd buy, are people who want to talk about the evil carbs or the magic carbs or the evil... I think we can get away from that a little bit. There are going to be some interesting things that we need to do to keep our guts healthy, and that's going to have to do with the foods we eat, absolutely. But in terms of, you know, obesity is all about carbs or something simplistic like that, I think the data just don't support that. And so if it were that simple, that'd be great. But it's, you know, as a first pass, a calorie is a calorie, and then we can talk about the caveats to that, I think I'd be fine with that. So I think one of the good takeaways of your book is that these hunter-gatherers are not doing the carnivore diet. No, no, I just reviewed this. So one of the people I work with over there is Brian Wood. He's a Hodza expert, been working there for over 20 years, I think. And, you know, he and I just went through all the long-term data we could find for Hodza food returns, because when you're in these camps that we work with, we measure all the food that comes in, and we see what they're eating. And so we have something like, you know, decades of food returns in this, you know, one of the only hunting and gathering groups that are still doing it, you know. And yeah, it's not a meat-heavy diet at all. You know, as a matter of fact, if anything, it's kind of a carb-heavy diet. But, you know, it's really a mix, and that's the, I think, the important thing there is it's not just one thing. You know, the idea that there's one perfect human diet, there's no evidence for that from the hunting and gathering literature I can tell you. And you've studied them. They, it's fascinating, and again, as my research at Yale as well, the diversity of the plants that they encounter in a year cycle is just mind-boggling. Yeah, yeah. Yeah, I mean, absolutely, you know. And if you think about, you know, what foods make it into your fridge on a weekly basis? You know, it's probably not the same number that you're going through if you're not at the Hodza camp. You know, and also, I think, is also important to mention, I'm not talking about this, but they don't have a lot of processed foods, do they? I mean, they have zero. They don't have any crops, no domesticated animals, even, you know? But they certainly don't have any packaged foods, and, you know, I think about the foods that come through an American household, over half the calories are these ultra-processed things, and, you know, it's not that it's any one particular nutrient, it's that it's just completely changed. And the way that your body handles that, the way that your brain handles it, it's just very different. So a lot to learn from Hodza diets and from other small-scale societies, for sure. Let's talk about, let's talk about breakfast. Break fast. Yeah. That's not a, something that these guys do. They don't wake up in the morning and start munching on Cheerios. No, they kind of wake up in the morning and have whatever was left over from last night, you know? If there is leftover, if there are leftovers from last night. And so, you know, I don't say, I wouldn't say that they sort of skip breakfast. They, not intentionally, you know, usually there's something left over that they'll have, but it's not this big sit-down and have 2,000 calories of anything, you know? It's sort of a small meal to get you going. You know, and a lot of times they'll head out without anything, and you know, when they find something, that's break fast, right? That's right, that's right, yeah, yeah. So, you know, for our viewers and listeners, what's one of the most important takeaways from your book that everybody can put into practice for their health today? Yeah, I'd say the big takeaway is diet and exercise are two different tools with two different jobs, right? The work we do with the Hatha says that maintaining your weight is mostly to do with your diet and what you're eating. A lot of other aspects of your health, heart health, you know, brain health, that has to do with the exercise and how you're spending those calories. And so, you know, you can't sort of trade diet and exercise. You kind of have to do both. That's the, you know, that's the tough news. The easy news is there's a lot of good ways to do that. You know, you can find an approach that works for you, but I think we have to think about diet for weight, exercise for everything else. That's what I would say. Yeah, I think you're absolutely right. There's, you know, exciting research about when we exercise, our muscles make hormones called myokines. And these things are incredible for producing BDNF and stimulating neuron growth. I mean, who knew that, you know, moving would help your brain? I mean, yeah. Really? Yeah, absolutely. And especially as people age, we're finding, this is a work, another guy I work with it in, when I work with the Hades, there's a guy named David Reiklin at USC now. And he's done really interesting work looking at people as they age. Physical activity seems to stave off a lot of cognitive decline. It seems to be protective against that for the reasons you're saying that it's not just your muscles, right? Exercise gets everywhere. And so really exciting stuff on that end of things too, for sure. Yeah, in the longevity paradox, I write about women who routinely exercise for most of their lives have an 80% reduction in Alzheimer's dementia compared to women who don't routinely exercise. And even women who carry the Alzheimer's gene and who eventually may develop Alzheimer's, it arrives 11 years later than if they didn't exercise routinely. Wow. And when you think about that, it's one thing to get Alzheimer's at 80 and quite another to get Alzheimer's at 91. I mean, 11 years of a good life at the end of your life is well worth the investment. Yeah, yeah. I mean, if you've got grandkids, it's the difference between losing touch when they're five or losing touch when they're 15. That's a big difference. Absolutely. Well, it's been a great pleasure to have you on the podcast today. And I really could talk to you for hours, and maybe we should. I'll call you up. So where can listeners learn more about you and your incredible work? Sure. Well, so I'm at Duke University and our lab website there, the Poncer Lab is pretty easy to find. I've got a funny name. So if you look for Herman Poncer, there aren't too many of us out there. We also, if you want to find out more about the Hodza, please check out thehodzafund.org. And of course, yeah, all of this stuff that we talked about today is in the book. Byrne, please check it out if you're interested in this work. Yeah, I know this is really fascinating. And, you know, your work up ends a lot of the current thought. And I like what you're bringing to this. So good for you and good luck with the book. And really appreciate having you on the podcast. Thanks so much. It was really fun. All right, take care. Okay, it's time for our audience question. This week's question comes from Julian Hahn on DrGundry.com who asks, does pressure cooking brown rice or black rice, forbidden rice, neutralize electrons? Okay, great question. One of the things you'll learn in the energy paradox is that black rice and red rice actually have quite a good content of melatonin. And you're going to learn in the energy paradox how good eating foods with melatonin can be for you. So shockingly, red rice and black rice are in the energy paradox as approved foods, as long as you pressure cook them. But please be aware that any rice comes at a cost because most of you are now aware that rice concentrates arsenic in the grain. And not a whole lot of us want a whole lot of arsenic in us. So you ought to view these as, in a way, special treats. But please, please pressure cook them. Now, even when you pressure cook rice, you want to get more resistant starch from your rice, and this is true with any starch. So remember, one of the keys is pressure cook your rice or cook a sweet potato, for example, and then refrigerate it, let it cool, and then reheat it. And the process of cooking, cooling, and then reheating actually dramatically increases the amount of resistant starch. And one fun fact, the best resistant starch out there is the purple sweet potato cooled and then reheated. The resistant starch content is out of this world. And interestingly, the purple sweet potato is 85% of the traditional Okinawan diet, and the traditional Okinawan diet made some of the longest living people in the world, one of the blue zones. So if you're going to have sweet potatoes, get the purple ones, they're pretty available now in most grocery stores, and cook it, cool it, and then reheat it. Great question. Now it's time for the review of the week. This week's review comes from, and I'm going to butcher this name, I apologize. M. Judd Figge. M. Judd W. Figge on Apple Podcasts who left a five-star review and wrote, Finding Dr. Gundry has changed my life. He is passionate about helping people and his well-researched way of living can help you too. Well, thank you, M. Judd W. Figge. Thank you very much. You know, all of your reviews are really super helpful. So if you haven't yet, please rate and review us on iTunes or wherever you get your shows. And I really take your reviews seriously, and I hope you can tell how excited I am to bring you these podcasts and to bring you my research, because as you know, I'm Dr. Gundry, and I'm always looking out for you. We'll see you next week. Before you go, I just wanted to remind you that you can find the show on iTunes, Google Play, Stitcher, or wherever you get your podcasts, because I'm Dr. Gundry, and I'm always looking out for you.