Burn: New Research Blows the Lid Off How We Really Burn Calories, Stay Healthy, and Lose Weight, Herman Pontzer (Avery, 2022). Compare these two covers. The one on the left, with the cover design that says “this is pop science to shelve with your Malcolm Gladwell,”
Thanks for the review. My sole comment is; I think, because over the last 60 years of trying to keep fit (and maintain weight within a 20 lb range(up and down), that exercise builds muscle that weighs more than the lost fat. Perhaps the studies of limited (or zero) weight loss over controlled time periods may have not taken into account the amount of fat that was lost and replaced by muscle.
Muscle also has higher energy burn per pound. I definitely felt I could eat more and maintain weight when more of my bodymass was muscle than if the same weight was fat.
I realize I'm a year late to this party, but isn't the big thing being missed (at least I didn't see it addressed at all) is that Hadza hunter gatherers are *much* smaller, men and women, in both stature and weight?
"How can we both be burning roughly 2000 calories a day?"
You're comparing extremely active 5' 3" 115 pound men and 4' 11" 95 pound women to 5' 10" 190 pounds western men and 5' 6" 170 pound western women. Raw number of calories burned daily isn't the relevant metric when comparing vastly different size / weight adults, why isn't this regularized by some height * weight metric, or at least fat free mass?
I realize the chart is trended by body weight, with imputed lines, but that isn't really doing that regularization in a way that makes sense either, considering Hadza men are probably 10% body fat and western men are 40% body fat, and Hadza men are well below any western men in the chart.
I've never got this generally when people talk about hunter gatherers. I've read Lieberman's Exercised (great book, highly recommend it), and he talks a lot about them too, but everyone seems to just not pay attention to the fact that they're tiny and have lower caloric needs total, and this in large part explains their calorie budgets.
I got the book from the library so I don't have it in front of me any more, but if you look at Pontzer's original paper you'll see he controls for body size (or, technically, fat-free mass). You can see his methods section here and the results below: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0040503#s2
Sorry if my flippant "roughly 2000 calories" was misleading -- this is indeed an obvious objection and I hope I didn't give the impression Pontzer missed it.
Ah thanks! Yeah, some great stuff in there, and FFM was indeed the largest predictor of TEE, as we'd expect.
I'd still take the basic conceit with a grain of salt - he's doing simple linear regressions, and the R^2's are all pretty low and noisy. I'm not sure it's shown to a standard I'd be happy with that we genuinely burn about the same, regularized by FFM - indeed, he calls it out himself referring to his figure S3 (TEE vs estimated BMR, with atrocious r^2's):
"These results, and the possible interaction between PAL and body size (Fig. S3), indicate more work on the physiology of traditional populations is clearly needed. Moreover, the lack of correspondence between TEE and daily walking distance (a large component of Hadza daily activity), or between TEE and maternal status (pregnant/nursing or not), along with other investigations of forager physiology, suggest that interactions between metabolic physiology, physical activity, and the environment are more complex than often thought."
AKA - results are noisy and unexpected, and we're not quite sure why we're getting these results. More study needed.
Still, extremely interesting directionally, and thanks much for sharing this next level of depth!
Hmm, if not exercising means that we burn more calories through other body processes which increase inflammation, does that mean that less exercise is the reason behind the increase in allergy prevalence in modern times compared to the past?
That’s certainly one implication. I’m not sure how you would disentangle it from the hygiene hypothesis, since unusually active populations tend to be unusually outdoorsy (and thus exposed to dirt, parasites, etc) populations, and a lot of allergies first show up in children small enough I’m not sure there’s a lot of difference in physical activity levels cross-culturally, but it’s not incompatible with Pontzer’s theory.
This is great, thanks. It's been plane* for years that the vanilla CICO model of weight had problems, but I had no good model to replace it with. Separating diet and exercise seems like a key insight and I'm going to have to let the ideas process for a while.
Have you read "The Emperor of Scent", it's a fun science story centered around the mechanism by which we smell things. And it's got all the 'right' actors. The hide bound, stuck in group think, establishment. And plucky individual researcher... I won't spoil the rest of the tale.
I'm not totally sold on Pontzer's model, but it seemed intriguing! And I haven't read Emperor of Scent, but I have read Burr's other book about perfume and, uh, I own both big volumes of Luca Turin's books about perfume, so it's very much the kind of thing I'll want up for middle-of-the-night reading after the baby's born.
Yeah kids! My kids are 24 and 22, (fully launched) and perhaps my only regret would be we didn't have more. But we started late. Yeah I have no idea about Pontzer's model, it's better than any other I've heard about. (My only other idea was some 'fat' set point in your body, but I'm an engineer so set points and control loops are my first thoughts.)
Oh please write a review about smell! But no hurry, kids first.
Thanks for the review! Fits into a broader pattern where efficiency and nuance (in this case, exercise and diet) matter way less than massive impacts to critical bottlenecks - I think you made a similar point in your review of Energy and Civilization.
Could be interesting to see if this theory foots on a broader level with the data we see in societies - e.g., assuming fixed energy burn, does the weight increase per person since ~1970 foot with the increased per-person calorie intake?
Thanks for the review. My sole comment is; I think, because over the last 60 years of trying to keep fit (and maintain weight within a 20 lb range(up and down), that exercise builds muscle that weighs more than the lost fat. Perhaps the studies of limited (or zero) weight loss over controlled time periods may have not taken into account the amount of fat that was lost and replaced by muscle.
Muscle also has higher energy burn per pound. I definitely felt I could eat more and maintain weight when more of my bodymass was muscle than if the same weight was fat.
I realize I'm a year late to this party, but isn't the big thing being missed (at least I didn't see it addressed at all) is that Hadza hunter gatherers are *much* smaller, men and women, in both stature and weight?
"How can we both be burning roughly 2000 calories a day?"
You're comparing extremely active 5' 3" 115 pound men and 4' 11" 95 pound women to 5' 10" 190 pounds western men and 5' 6" 170 pound western women. Raw number of calories burned daily isn't the relevant metric when comparing vastly different size / weight adults, why isn't this regularized by some height * weight metric, or at least fat free mass?
I realize the chart is trended by body weight, with imputed lines, but that isn't really doing that regularization in a way that makes sense either, considering Hadza men are probably 10% body fat and western men are 40% body fat, and Hadza men are well below any western men in the chart.
I've never got this generally when people talk about hunter gatherers. I've read Lieberman's Exercised (great book, highly recommend it), and he talks a lot about them too, but everyone seems to just not pay attention to the fact that they're tiny and have lower caloric needs total, and this in large part explains their calorie budgets.
I got the book from the library so I don't have it in front of me any more, but if you look at Pontzer's original paper you'll see he controls for body size (or, technically, fat-free mass). You can see his methods section here and the results below: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0040503#s2
Sorry if my flippant "roughly 2000 calories" was misleading -- this is indeed an obvious objection and I hope I didn't give the impression Pontzer missed it.
Ah thanks! Yeah, some great stuff in there, and FFM was indeed the largest predictor of TEE, as we'd expect.
I'd still take the basic conceit with a grain of salt - he's doing simple linear regressions, and the R^2's are all pretty low and noisy. I'm not sure it's shown to a standard I'd be happy with that we genuinely burn about the same, regularized by FFM - indeed, he calls it out himself referring to his figure S3 (TEE vs estimated BMR, with atrocious r^2's):
"These results, and the possible interaction between PAL and body size (Fig. S3), indicate more work on the physiology of traditional populations is clearly needed. Moreover, the lack of correspondence between TEE and daily walking distance (a large component of Hadza daily activity), or between TEE and maternal status (pregnant/nursing or not), along with other investigations of forager physiology, suggest that interactions between metabolic physiology, physical activity, and the environment are more complex than often thought."
AKA - results are noisy and unexpected, and we're not quite sure why we're getting these results. More study needed.
Still, extremely interesting directionally, and thanks much for sharing this next level of depth!
Hmm, if not exercising means that we burn more calories through other body processes which increase inflammation, does that mean that less exercise is the reason behind the increase in allergy prevalence in modern times compared to the past?
That’s certainly one implication. I’m not sure how you would disentangle it from the hygiene hypothesis, since unusually active populations tend to be unusually outdoorsy (and thus exposed to dirt, parasites, etc) populations, and a lot of allergies first show up in children small enough I’m not sure there’s a lot of difference in physical activity levels cross-culturally, but it’s not incompatible with Pontzer’s theory.
This is great, thanks. It's been plane* for years that the vanilla CICO model of weight had problems, but I had no good model to replace it with. Separating diet and exercise seems like a key insight and I'm going to have to let the ideas process for a while.
Have you read "The Emperor of Scent", it's a fun science story centered around the mechanism by which we smell things. And it's got all the 'right' actors. The hide bound, stuck in group think, establishment. And plucky individual researcher... I won't spoil the rest of the tale.
*sorry my writing sucks :^)
I'm not totally sold on Pontzer's model, but it seemed intriguing! And I haven't read Emperor of Scent, but I have read Burr's other book about perfume and, uh, I own both big volumes of Luca Turin's books about perfume, so it's very much the kind of thing I'll want up for middle-of-the-night reading after the baby's born.
Yeah kids! My kids are 24 and 22, (fully launched) and perhaps my only regret would be we didn't have more. But we started late. Yeah I have no idea about Pontzer's model, it's better than any other I've heard about. (My only other idea was some 'fat' set point in your body, but I'm an engineer so set points and control loops are my first thoughts.)
Oh please write a review about smell! But no hurry, kids first.
Thanks for the review! Fits into a broader pattern where efficiency and nuance (in this case, exercise and diet) matter way less than massive impacts to critical bottlenecks - I think you made a similar point in your review of Energy and Civilization.
Could be interesting to see if this theory foots on a broader level with the data we see in societies - e.g., assuming fixed energy burn, does the weight increase per person since ~1970 foot with the increased per-person calorie intake?