Ep. 61: Why Exercise Won’t Help Weight Loss with Herman Pontzer
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Curious about how to lose weight? Most people think that when you want to drop pounds, you should eat better and exercise more. But Duke University Associate Professor and internationally recognized pioneer in human metabolism Herman Pontzer (above) argues that exercise — while really important for mental and physical health — plays no part in weight loss. In his new book, Burn: New Research Blows the Lid Off How We Really Burn Calories, Lose Weight, and Stay Healthy, Pontzer says the only way to move the number on the scale is by consuming fewer calories. Here, Pontzer is in conversation with Dr. David Macklin, director of weight management at Medcan. It’s a revealing and entertaining conversation that will have you rethinking how you eat, move and live.
Insights
Women have a lower total energy expenditure compared to men. That’s because women tend to carry more fat for reproduction. Women also tend to be smaller—on average —than men. “The biggest difference is just size and particularly the amount of lean mass that [women] carry,” Pontzer explains. As a result, it can be more difficult for women to lose weight as quickly as men are able to. (47:58)
Reproduction is energetically costly. Pregnancy costs 70,000 kilocalories. Breastfeeding also takes a lot of energy. “Any mother out there doesn't need me to tell them that, they understand that intuitively,” Pontzer says. (50:30)
When it comes to weight loss, it’s not exercise that’s the determining factor of whether you pack on the pounds or not. It’s diet. “You’ve got to focus on how many calories you bring in. That's going to be where you're going to have the best leverage to try to change and manage your weight,” Pontzer argues. (51:59)
Studies show that we can’t control our metabolic rate. Exercise doesn’t speed it up. If you try to lose weight too quickly with starvation diets, your metabolism will pull back. “The best approach would be to pull back kind of slowly to not try to lose five pounds a week, or whatever it is. Don’t go too far too fast,” Pontzer recommends. “You want to find a diet that makes you feel full on fewer calories.” (57:13)
Links
Get your copy of Burn by Herman Pontzer at Amazon or Indigo.
This New York Times article, Dieting vs Exercising for Weight Loss, published in 2012, was one of the first to share findings from Pontzer’s ground-breaking research on the Hadza tribe in Tanzania.
In The Exercise Paradox, published in the Scientific American, Pontzer shares his experiences in Tanzania, drawing energy expenditure comparisons not only with the Hadza but with great apes, too.
This Daily Mail article, Hitting the Gym Won’t Make You Thin, Pontzer explains how active people burn more calories on exercise, but spend less energy on other stuff, such as immune functioning.
In this National Post article, Kids Should Eat Better Because Exercise is a Terrible Tool for Losing Weight, Pontzer compares the calorie expenditure of kids from the foraging and farming Shuar tribe in the Amazon to kids in America and U.K. to find that the less active kids still burned the same amount of calories. He argues the only way to deal with child obesity is through diet.
Connect with Pontzer on Twitter.
Why Exercise Won't Help Weight Loss with Herman Pontzer final web transcript
Christopher Shulgan: Welcome to episode 61 of Eat Move Think. Christopher Shulgan here, executive producer. If you've gained the COVID-19, or even just a few pandemic pounds, then you might be thinking you should try to exercise more, to lose some weight before summer rolls around and you attempt to squeeze back into your favourite shorts. But here's the thing: getting exercise is a great idea. It's good for your heart, your lungs, toning your muscles, not to mention the positive impact physical activity has on depression, anxiety, relieving stress, improving your memory and helping you sleep better. But the one thing exercise has absolutely no effect on? The number that appears when you step on that scale. That's the argument Herman Pontzer makes in his new book, Burn: New Research Blows the Lid Off How We Really Burn Calories, Lose Weight, and Stay Healthy.
Christopher Shulgan: Pontzer is an anthropologist and internationally-recognized researcher in human metabolism. He's also associate professor of evolutionary anthropology at Duke University. Over the past two decades, Pontzer has studied the Hadza, a modern hunter-gatherer tribe in Tanzania. The Hadza spend eight, nine, 10 hours a day on their feet, burning calories. That's a very different lifestyle from our very sedentary one here in North America, which sees us sitting in front of our computers for eight, nine, 10 hours a day, then moving to the dining room table for dinner, to the couch to watch TV, then to bed, only to start the same routine over again the next morning.
Christopher Shulgan: So you'd think that the Hadza would be a much thinner group of people, with lower body fat than those in Western populations. But that's not the case. While the physical activity level is much higher in the Hadza men and women, their total energy expenditure and their metabolic rate was no different to that of Westerners. That's because the only way to effect a change on your weight is through calories in. In other words, your diet. Here's Herman Pontzer's conversation with Dr. David Macklin, Medcan's director of weight management.
David Macklin: Hi, everyone. I'm David Macklin, and welcome to the Eat Move Think podcast. Today's going to be a real exciting conversation with Herman Pontzer. Herman, I'm super excited to have you here and to jump in and have some discussions around the really remarkable, game-changing work that you're doing in the field of energetics and metabolism. So welcome. You know, Herman, I just want to jump in. If I go right now into my basement and jump on my treadmill and burn, you know, 200-300 calories of energy in my workout, your findings describe that over the next number of either hours or days or weeks, my body is then going to burn about 200-300 calories less than it was going to, just to make up for that silly thing that I did, trying to increase my daily energy expenditure. And I'm kind of not going to get credited those calories, right? And that's mind blowing to most people. So I'd love to hear kind of a little bit about your experience of discovering that yourself.
Herman Pontzer: Yeah, well, that was a surprising observation to me, too. And I think you got it exactly right. I'm an anthropologist, evolutionary biologist. I'm interested in how humans evolved. And so I'm very interested in how our bodies burn calories, because that's kind of where the rubber hits the road in evolutionary biology: turning energy into kids, right? That's kind of all evolutionary biology cares about. And so I was trained under the sort of traditional way of thinking about this, which is the more you move, the more you burn. And so species that are more active will burn more energy than species that are less active, and if we look within a species like within humans, if you're more active, you'll burn more calories than if you're not as active. And that's just kind of the way that it's been thought of is it's so intuitive that it's hard to imagine a different way of thinking about it, actually.
Herman Pontzer: And so my colleagues and I went and we wanted to measure the total energy spent per day because we wanted to know just how big of an impact physical activity has in a context that's sort of more ecologically relevant for humans, which is a hunting and gathering community, right? Because cities and supermarkets are all really new and strange and weird, and we're actually evolved as hunter gatherers. And so there are a handful of populations left that still hunt and gather. So there's these wonderful opportunities, places to go and sort of see what that lifestyle does to your body.
Herman Pontzer: And so we went and worked with the Hadza community in northern Tanzania, this hunting and gathering group. You know, we got the funding in 2009. I think we got the funding predicated on the idea that we're going to see these really high expenditures. And we measured total energy expenditures with men and women using this state of the art method, which is called doubly labelled water, an accurate measurement of energy expenditure averaged over about a week or 10 days. And so it's not just like, you know, a one-off snapshot, it's like a pretty good measure of daily expenditure. And we were totally shocked to learn that, even though they're really physically active, you know, Hadza men and women get more daily activity in a day than most of us get in a week, their total daily energy expenditure was still the same as it is for men and women in the US and Europe and other industrialized countries. So that was a huge shock to me.
Herman Pontzer: And then the next shock was, as I kind of chased this down, was that it shouldn't have been a shock. Because when you actually look at other species and other models of looking at the impact of activity on expenditure, what you see again and again and again, across human groups—across species even—is that the body is juggling its different requirements, its different tasks. Exercise is one of those tasks. And it's juggling them in a way to keep total energy expenditure within a pretty narrow range. If we exercise, especially when we kind of do it long term, we adopt an exercise lifestyle, so our body has time to adjust to it, well, that adjustment will mean less energy on other stuff. And so the total energy we spend day to day is actually not going to be much different, maybe no different at all, than when we started our exercise or before we started our exercise.
David Macklin: So Herman, that's a ton of stuff. And I want to break that down step by step. You guys are going to Tanzania, and you're using a technology that allows you to really get a sense of the total amount of energy that someone is burning in a day. And it's called doubly labelled water technique.
Herman Pontzer: Yeah, that's right. So the way that you do it in the lab, in your office, is the way that it's typically done, and actually has been done for over 100 years now, which is capturing people's expired air, and using the oxygen content and CO2 content of that air to calculate how many calories they're burning at that moment, minute to minute. And that's great if you want to measure the energy expenditure of somebody who's resting in your office to get a resting metabolic rate. Or you can do that with different techniques. You can do that for somebody who's, like, on a treadmill or doing an activity kind of thing. It's a snapshot in time, and it's not practical for measuring energy expenditure over the course of days, right? Which is what we really want to know. We want to know about total energy balance, total energy expenditure.
Herman Pontzer: For that, what you do is this technique that uses isotope tracking to calculate how much carbon dioxide your body produces every day. It's a really cool technique. So basically, you drink some water that's isotopically tagged. So some of the hydrogens are deuterium, some of the oxygens are oxygen-18. Those are just different forms of hydrogen and oxygen. So we can use those like tracers. And then after you drink that water—it's totally stable and not toxic or anything like that. It's very safe. We use it all the time. After you drink that water, those tracers go up, they diffuse through your body. So if we get a urine sample a few hours after you drink it, we'd see those levels are much higher. We could measure that. And then over time, we see that you flush those isotopes out. How do you flush them out? Well, you flush them out with the water that you lose in urine and sweat and water vapor that you exhale. You also lose the oxygens as the CO2 that you breathe out, which is a really kind of cool chemical trick that is happening in your body. And so if we track the depletion of those isotopes in your urine samples over a week or so, every couple days we get a sample, we can measure down, down, down as they go, and we measure the depletion rate. We can compare the depletion of hydrogen—which is our water turnover signal, our water loss signal—to oxygen, which is water plus CO2. Well, the difference in those rates is CO2. And so we get a really accurate measurement of CO2. You can't make CO2 without burning calories, you can't burn calories without making CO2. So this is the gold standard, right? This is not an estimate, we're not making stuff up here, we're not guessing. It's a really accurate way of doing it.
David Macklin: So then you take this technology to compare with this great tool, the total energy expenditure of, say, that the mostly sedentary North American person, and comparing this to a group who theoretically are burning a whole bunch more energy because of their high levels of physical activity, this hunter gatherer group in northern Tanzania. And so you guys get there and you're going to prove that this hunter gatherer group is burning way more energy, because they're digging, and they're climbing, and they're doing a ton of walking. And so what's that like when you first get the start getting the results back of the measurements? What do you think? So I think you mentioned surprise, but do you realize that this is kind of game changing when you start to see that data?
Herman Pontzer: I didn't realize how much of a game changer it was going to end up being, to be honest. We had a short field season at the end of 2009, and we had some preliminary data that looked like it wasn't much different than other Westerners. And I thought, oh, I bet when we get a bigger sample, we'll see the difference.
David Macklin: Right.
Herman Pontzer: And then we got the bigger sample, and of the 30 men and women, still no difference. And I thought, what the heck is going on? And the first thing I did is—you know, the first thing you think of, I mean, I hope this is true for any researcher, but certainly for us—the first thing we thought was that we must be wrong.
David Macklin: Right. Something's wrong.
Herman Pontzer: You know, Bill Wong at Baylor, one of the leading labs in the world doing this kind of stuff, I went back to him and I said, "Bill, tell me what's going on. Show me where we did it wrong, or show me what"—you know? And he said, "No, no. These are right. These are good." What I was realizing is, as I talked to him and Dale Sheller and a couple other people about this, the realization was, if you spent your career measuring energy expenditures, you know. These folks already kind of knew, but we're kind of not being heard, I think. That there really isn't this correspondence that we think there should be between activity levels and expenditures.
David Macklin: So just to jump a little bit clinical, because you talk about this in your book as well, in the book Burn. I describe the constraint model of energy expenditure quite regularly with my patients and have been since 2016, and appropriately, this is part of clinical medicine when you're counselling individuals who are living with obesity to help them understand what we call the place of exercise in weight management. And you talk about this in the book so well, but when I go through the constrained model of energy expenditure with patients, probably about 90 percent of the time, the next sentence out of a patient is, "Oh, so why am I exercising?"
Herman Pontzer: Yeah.
David Macklin: Yeah, that must be something kind of you faced regularly. I'd love to hear what that's been like for you.
Herman Pontzer: Oh my gosh, yeah. So first of all, when the Hadza data came out, and we suggested in that first Hadza, paper in 2012, hey, maybe it doesn't work like we think it does, we hadn't formulated the whole constrained energy idea yet, but the inklings were there. Oh, my gosh, the pushback we got back was really severe, right? People hated it.
David Macklin: Yeah.
Herman Pontzer: Because they thought, well, you're saying we don't have to exercise. And it didn't help that the media, the clickbait headlines—it's a double-edged sword of getting your research covered in the media. You want people to know about what you found, that's the reason you did it. But, you know, you kind of can't control how that gets messaged very well. And certainly, I wasn't doing a good job, I guess. And yeah, the clickbait headlines were pretty atrocious, you know? "You never have to exercise again," kind of stuff. So yes, that reaction, I think, is normal. The reason that you should exercise is that those adjustments are part of what makes exercise so good.
David Macklin: So this is really cool. So you're describing—I think this is such a key point, you're describing in your book and with your data, that if the body is going to have to find less energy to burn somewhere else, because you just ran on the treadmill and burned 300 calories, and it wants to keep your total energy expenditure within this narrow band. So it's going to have to burn less somewhere. And you start to talk about how it goes to the less necessary kind of things, right? And explain to me, by becoming more efficient in the less necessary things, this may be a real insight into the underlying health benefits of exercise. Yeah, I'd love to hear more about that.
Herman Pontzer: Yeah. So you know, again, we're an evolved organism, right? And for 500 million years of vertebrate evolution, our metabolisms have been tuned. You know, metabolism is this multi-headed beast that has to do every task in your body, and your bodies are really well tuned to juggle all those priorities. And after 500 million years, you'd expect that our bodies are pretty good at figuring out what to cut out first.
David Macklin: Right.
Herman Pontzer: When things get tough, you cut out the things you don't need first. Your prioritization is pretty good. And so what humans seem to cut out—and this is something that we're actively researching in the lab, so we don't know all the answers here yet, but this is what we see when we look at this—people are cutting down inflammation, right? Inflammation is immune system activity that you don't really need to do. Chronic background inflammation isn't necessary. Acute inflammation to respond to something, yes, you need that, but a chronic inflammation is not necessary. You crank that down. Stress reactivity. So cortisol levels, epinephrine levels, right? We all get a bump whenever we get stressed, which over the course of our day happens multiple times. But if you're somebody who exercises a lot, or just regularly, that bump is smaller, and you return back to baseline levels faster.
Herman Pontzer: There's a nice study of this with women doing exercise to treat depression. I think with just moderate jogging versus being sedentary, they were producing, like, 30 percent less cortisol, 30 percent less epinephrine over the course of a day. We think that exercise helps you keep your reproductive hormones in a more healthy place. Hormones, estrogen and testosterone and progesterone levels are actually really high in the West, in industrialized countries, compared to what we see in more physically-active populations. And by the way, those physically-active populations, they don't have any problem with fertility. So we're not talking about cutting that out, but just to get you into a sort of healthier level. And we know that exercise is really protective against reproductive cancers, like prostate cancer, breast cancer. So I think there's a syndrome here, there's a constellation of responses, that are your body prioritizing and spending less energy on all this stuff that you don't need to be doing, and that's why it's so darn good for you to exercise.
David Macklin: So a quick tangent, because there'll be a lot of our listeners who are female, and you describe kind of in a nice, efficient way, why women compared to men will have overall lower total energy expenditure, lower metabolic rate. I'm wondering if you might speak to that, because the gut instinct of so many women out there are, "I don't burn that much," right? My husband, he started this diet, and he's down by 10 pounds now. So maybe you could speak to that to kind of fill in our listeners—especially the females—as to why the difference in metabolic rate between men and women?
Herman Pontzer: The biggest difference is just size, and particularly the amount of lean mass that you carry. So women just naturally tend to carry a bit more fat. Again, that seems to be kind of to carry a bigger reserve for reproduction, because reproduction is so energetically costly that evolution has upped the amount of body fat that women just naturally carry. Women tend to be smaller anyway, just on average. Of course, you'll find variation there, but women tend to be smaller anyway. And then they also tend to carry a bit more fat. So the lean mass is even smaller still. And so yes, total energy expenditures are a bit smaller for women.
David Macklin: So the total amount of energy we're burning in a day, just to kind of stay at a 10,000-foot level, every cell in our body does work and needs energy. And how many? 37-trillion cells?
Herman Pontzer: 37-trillion cells, give or take.
David Macklin: Give or take some decimal points. So 37-trillion cells, all doing work in our body. So the smaller someone is, to start off with, just the less cells that are there doing work?
Herman Pontzer: Yeah, it really is that simple, you know? If you think about each of your cells as a tiny factory, and they each need to get energy in and get nutrients and burn them off to do their work, the work their little factory does, well, if you are bigger and have more of those factories, you're going to burn more calories. It's really that simple.
David Macklin: So cells that are part of lean body mass, like muscle, and cells that are part of our stores of fat, the lean body cells use more energy than fat cells?
Herman Pontzer: Yeah, that's right. Fat cells are pretty quiet in terms of just how much work they're doing. And that's based on just their biology. Also, we measure these sort of on a per-gram basis. And on a per-gram of fat, if you have them full of lipid, then there's actually less cell and more fat there. Whereas if you look at a gram of liver, it's kind of pure cells all working, if that makes some sense. So the density of active parts of your cells are higher in active tissues.
David Macklin: Cool. And then because of the energy requirements of reproduction, and the importance of stored energy, women will carry around just naturally more of the fat cells rather than the lean tissue.
Herman Pontzer: That's right, yeah. I mean, a pregnancy cost something like—I'm just going to try to remember—I believe it's about 70,000 kilocalories, right? Which is a ton of calories. And any mother out there doesn't need me to tell them that. They understand that intuitively. And then if you breastfeed your baby, that takes a lot of energy too, as much as pregnancy does actually, for the first few months. And so evolution has prepared you. You don't want to kind of go into that without a reserve fuel tank. And so women just happen to carry more fat because of that.
David Macklin: So what about what about the other side of the equation then? So an obesity epidemic globally—let's call it the other pandemic. And if you can't really run or jump or climb out of this, and that's not an effective method of losing weight then, does that point us then naturally to the other side of the energy equation? How do you kind of communicate that? You must get that a lot, right?
Herman Pontzer: Yeah. No, I think you're absolutely right. I think fundamentally, we have to understand that weight gain or weight loss or weight balance, it's fundamentally about how many calories are coming in in terms of your diet, and how many calories you're burning off. And my work shows, along with other people, that it's really hard to change the energy part of that. It's really hard to change how many calories you burn. And so you got to focus on how many calories you're bringing in. That's going to be where you're going to have the best leverage to try to change and manage your weight—it's diet. Now people don't always like to hear that, because people have been trained to be suspicious of "calories-in, calories-out," right? There's a lot of kind of smoke and mirrors about, "Oh, it's not about calories." I promise you, it is really just about calories. And so we've got to focus on the diet to fix the calorie issue here.
David Macklin: You're saying that if you're going to focus on your weight, so there's, let's say, a subject of eating healthfully, which is a separate and wonderful subject, there's a subject of exercise and fitness and strength and flexibility. But you're saying the subject of weight really does boil down in your experience, to overall the amount of calories that we take in?
Herman Pontzer: That's right. Diet is the tool you need to focus on for weight.
David Macklin: And by diet, you're talking about overall energy, like, how much you take in. Yeah, the total number of calories.
Herman Pontzer: Yeah, exactly. Exactly. It is. The reason I would say diet and not just calories, is that different foods push people to overconsume, right? I mean, obesity isn't a choice. The pushback you get back—I've gotten anyhow, and I'd be very curious to hear your perspective on this, but the pushback I've gotten is, well, if you focus on diet, then you're blaming people for overeating. And that's part of fat shaming and doesn't help. And I agree that fat shaming doesn't help and is not good for anybody or anything. But I would say that when we say let's focus on diet and calories in, that doesn't carry with it blame about overeating, because most people don't choose to overeat. The question is, why are the foods that we're surrounded with leading so many of us to overeat? And I think that's the kind of societal food environment question that we have to think about.
David Macklin: Right. So we published in 2020, clinical practice guidelines for the treatment of obesity in Canada. We talk about this concept of challenging what is internalized weight bias. So the messaging out there that is external, that somehow struggling with weight is a flaw in character, a lack of willpower, someone just not trying hard enough. And eventually, those thoughts and characteristics and traits get internalized, and someone struggling with weight believes themselves. Unfortunately, those thoughts become internalized, that their struggle is because of a moral failure of them just not trying hard enough. And really, where we've landed on this is—and I think this ties really well into your work, where we've landed on this is the method of communicating is so important that actually struggling with weight is a real medical condition, centred in the brain. Much is conferred genetically. And as someone loses weight—I'm curious your thoughts on this—we know that certainly, Kevin Hall talks a lot about how certainly appetite goes up. So I'd love to hear a little bit more kind of your thinking. What about this other homeostatic response? What about this other metabolic compensation that anyone who's listening is going to face if they start losing weight? Have they been advised about that? What would be your advice to them?
Herman Pontzer: It's just more evidence that we're not in the driver's seat when it comes to our metabolic rate. You can't rev it up with exercise, and if you try to lose weight too quickly with kind of a starvation diet sort of thing, your metabolic rate will pull back. Yeah, I think we don't know enough about how severe that metabolic response will be, that sort of breaking will be in response to how quickly we pull back on calories, right? So I think that the best approach would be to pull back kind of slowly, to not try to lose five pounds a week or whatever it is, not go too far too fast. And I think also, you want to find a diet that makes you feel full on fewer calories. So if you are feeling miserable and hungry, then you can be sure that all of those neural circuits that are also going to be reducing your metabolic rate, those are all active, because usually they can be active even when you're not aware of it. If you are aware of it, you can be sure they're active. And so finding a diet that helps you feel full on less is the Holy Grail. And, you know, there are plenty of snake oil salesmen out there who will tell you exactly how to do that. And I don't think there is any one way to do that for everybody. I think that's the big lie here is that I have the one diet for you that works. No, but we have some principles that people could try. And, you know, you've got to individualize it for yourself and find what works for you. But that is the trick, is what diet works for you that you don't feel hungry all the time, but you are eating a few less calories.
David Macklin: If you stand back to a more of a 10,000-foot level, we start to realize in weight management science that hunger versus fullness may be a much smaller player than we think. Instead, kind of the homeostatic system seems to be overpowered by a system just above it called the hedonic or reward or motivation system. So where we would land is, rather than kind of working on making sure your satiety and fullness is enough—which people can be pretty good at and yes, the principles of protein and fibre can help with—but we really introduce what are the underlying causes of someone overconsuming calories, which we think of as much more of a conditioned response, kind of a Pavlovian learning. If you stand back, a brain built for—especially the midbrain, which generates wanting and desire and urge and craving, which is different from physical hunger—so we think more midbrain, and how certain sets of cues have been associated with the ultra-processed food and abundant food. So many times that now a learning is taking place in the human brain such that, you know, if the couch, the TV and the end of the day has been paired thousands of times with a hyper-palatable food or an abundant food, there's a conditioning that's taken place, another neurological kind of sensitization process called incentive motivation or cravings or desire or urge or wanting is kind of a common phrase.
David Macklin: And so we help patients learn that these settings now, actually—because you'll hear a lot from individuals that you know, "Was I hungry? No. Actually, it was 9:00 p.m., and I had eaten dinner at seven. Like, was I physically hungry? No. But I certainly had my attention drawn to food."
Herman Pontzer: That makes sense, you know, and that speaks to something that helps me make a connection, which I think is interesting: that humans are the only primate that shares food to the extent that we do, right? And that's an old, old old piece of our puzzle, that's an old strategy that's unique to us. It started probably two and a half million years ago with hunting and gathering, you know? And you think about hunting and gathering. What other species has half the group do one thing and half the group do another thing? And how can that even work unless you have the "And?" And you're sharing at the end of the day. And you share the hunting with the people who did the gathering. And so, you know, two and a half million years of selection to be pro-social, to be—and particularly to be pro-social about food and sharing food, means that, just like humans come into the world or born into the world ready to learn language, and we're ready to walk on two legs, and all these other things our brains are built to make us want to do, we are built to want to share, and specifically to want to share food and to be social and to be in that network, that social network. And I think that what you're describing just speaks so powerfully to the applied piece of that today, which is that it's the social world that can be as big of a driver for eating and food, right? Because you're sharing the food like we're talking about, as it is the actual—the kind of cues that a dog might respond to, which is "Oh, I'm actually hungry right now," right? So that's interesting. That's really a nice piece to connect those two.
David Macklin: So we only have a few minutes left. I thought we might leave just a few minutes at the end, because I love the kind of the discussion of the scientist. You're sitting in the fields of Africa, you're living amongst the bugs. I mean, this is real kind of applied science. I'd love to hear a little bit more about that experience.
Herman Pontzer: Yeah, well, that was one of the reasons I wrote the book, and one of the things that was so fun about it was talking about those experiences, either with the Hadza or doing archaeology in Georgia, or doing rainforest ecology with chimpanzees. It was really just fun to do all that stuff. I feel so lucky to have the career I have. But yeah, you go out and embed with the Hadza community, there's nothing that can really prepare you for it, other than camping. You know, it's basically a big camping trip with all your science equipment that you can pack into a Land Rover. And so, you know, it just feels so foreign. I think the arc for me is—and you kind of re-experience this every time you go back—you get to Africa after a big long trip on the airplane, and you get to Arusha. Arusha is the last sort of little city that you can kind of really stock up in. And you're going to the markets, and you're shopping for the food you're going to eat for the next month, and you're buying mosquito nets to give out to the community, and you're making sure everything's in order. And you're getting your Land Rover checked out to make sure it's going to keep together, because if that breaks, you're really done. And you're getting every last thing done, and it feels like you're going to the moon, you know? Because there really is—once you get out there, you can get back but gosh, it'd be tough. So, you know, you don't want to. You want to be able to be out there in your capsule in a Hadza camp and doing your thing.
Herman Pontzer: Everything's in Swahili. And my Swahili is okay, but not great. So it feels kind of foreign that way, trying to get by in a foreign language. Yeah, you get packed up, everything goes, and then you're just driving and driving. And you go through little towns and then even smaller towns. And then the last little outpost of a town is called Mangola, in the dry kind of savannah there on the shores of Lake Eyasi. And then you're on just Land Rover track. And then you're off the Land Rover track and you're still driving, and you're following—you know, Brian Wood, who's my colleague, he's got—in his GPS, he's got every Hadza camp he's ever visited. He's like, "Let's try this one," you know? And so you're following the track on your phone while you're driving through. It's kind of crazy. And you roll up into this Hadza camp, and you feel like you walked into—I don't know what it feels like. Maybe like you walked into a National Geographic magazine, or you walked into—I mean, it's kind of cliche, but it really does feel like that. There's grass huts around, kids running around, adults coming back, men walking around with bow and arrows, you know? It feels really foreign. And it's just incredible and amazing. And it's wonderful.
David Macklin: Hey, Herman, thanks so much for taking the time. Thank you so much, just personally, for the work that you're doing. You're helping a ton of people where the rubber hits the road. And thanks for taking the time today for our discussions. Really, really interesting. Yeah, much appreciated, and keep up the good work.
Herman Pontzer: So fun to talk with you. Thanks so much.
David Macklin: All right, Herman. All the best.
Christopher Shulgan: That was Medcan director of weight management Dr. David Macklin in conversation with the world-renowned expert in human metabolism Herman Pontzer of Duke University. Pontzer is on Twitter @hermanpontzer.
Christopher Shulgan: I'm executive producer Christopher Shulgan. Find show notes and full episode transcripts at EatMoveThinkpodcast.com.
Christopher Shulgan: Eat Move Think is produced by Ghost Bureau. Senior producer is Russell Gragg. Chantel Guertin and Tiffany Lewis produced this episode. Social media support from Emily Mannella.
Christopher Shulgan: Remember to rate and subscribe to Eat Move Think on your favourite podcast platform. Follow our host Shaun Francis on Twitter and Instagram @Shauncfrancis—that's Shaun with a U—and Medcan @medcanlivewell. We'll be back soon with a new episode examining the latest in health and wellness.