Herman Pontzer

Excited to announce my new book ADAPTABLE coming this Spring!

!!Announcing the next round of Isotope Grants for DLW projects!! Successful proposals get free isotopically enriched water for human DLW studies. Proposals due Sept 1. Details & application here: sites.duke.edu/pontzerlab/dlw…

Honored to be elected a @aaas Fellow! More important than ever to promote solid science and communicate it widely. trinity.duke.edu/news/duke-prof…

In this episode, evolutionary anthropologist Dr. Herman Pontzer (@HermanPontzer) of the world's leading researchers on human metabolism and energy expenditure at Duke University—joins the show to share what decades of fieldwork with the Hadza hunter-gatherers of Tanzania have revealed about how our bodies really work. We explore what hunter-gatherers actually eat (spoiler: it's not the all-meat paleo diet you've been sold), why the healthiest hearts ever measured belong to a community whose staple foods are unrefined carbohydrates, and the shocking finding that the Hadza—despite walking up to 19,000 steps a day—burn no more calories than sedentary Americans. Dr. Pontzer explains his groundbreaking "constrained energy" model and why your body quietly reallocates energy from inflammation, stress hormones, and reproductive functions when you exercise more, rather than simply burning extra fuel. We also dive into Dr. Pontzer's landmark Science paper on metabolism across the human lifespan, which upends the popular belief that a slowing metabolism causes middle-age weight gain. The data from over 6,000 people show that your metabolic rate holds remarkably steady from your mid-20s all the way into your late 50s—meaning diet, not metabolism, is what's really driving the obesity crisis. Dr. Pontzer shares practical takeaways: prioritize minimally processed foods, get your fiber and protein, and stop blaming your metabolism for weight gain. The conversation closes with a powerful reflection on what modern life has lost—community, presence, and a healthier relationship with time—drawn from his years living among the Hadza. Dr. Pontzer also introduces his new book Adaptable, a guide to understanding human biology through the lens of evolution. Timestamps 00:00 Introduction to Human Metabolism and Energy Expenditure 02:35 Hunter-Gatherer Diets: What Do They Really Eat? 09:38 The Role of Honey in the Hadza Diet 10:25 Translating Evolutionary Diets to Modern Contexts 12:14 Health Status of Hunter-Gatherers 14:50 Lipid Profiles and Heart Health in Hunter-Gatherers 19:26 Adaptations of Arctic Diets: The Inuit Example 21:45 Variability in Animal Source Foods Among Hunter-Gatherers 24:29 Debunking Dietary Myths 29:11 Energy Expenditure and the Hadza 32:58 Metabolism Across the Lifespan 42:07 Nutritional Insights from Hunter-Gatherers 47:14 Lessons from the Hadza: Community and Time 50:14 Introducing 'Adaptable': Understanding Human Biology

@dietiti3n @TyBealPhD Yes that could definitely contribute. The analyses we’re discussing here hold LBM constant so we can compare across people of different sizes. But in absolute terms, lower LBM will lead to lower energy expenditure per day.

@TyBealPhD @HermanPontzer What about LBM loss over that time frame? Could this be a reason for perceived metabolic rate lowering ?

I turned 40 today and my metabolism is not slowing down. @HermanPontzer explains the real reason why we gain weight in middle age.

Yes, people training for ultras burn more energy each day than normies. We’ve shown that too: cell.com/current-biolog…

@davykevinp @TyBealPhD Work like your paper shows nicely that compensation isn’t 100% in well nourished pops. We’ve shown a positive effect of PA on TEE in other studies. Doesn’t mean compensation isn’t happening. In controlled intervention studies we can see that it is.

@davykevinp @TyBealPhD I think we laid this out in the recent 2026 paper pretty clearly. Compensation is typical. The degree seems to depend on calorie availability. In Hadza & some others compensation is ~100%.

It's crazy that the Hadza hunter-gatherers burn the SAME calories as we do in the U.S. even though they walk 15,000 steps per day 🤯

@davykevinp @TyBealPhD It’s remarkable to me that the conversation has changed from “Hadza have higher TEE” to “actually (some) Americans have higher TEE”. FWIW from our study last year: accounting for FFM etc Hadza HZA = US adults pnas.org/doi/10.1073/pn…

@HermanPontzer @TyBealPhD Some do! Compensation? TBD

@TyBealPhD @davykevinp Yep, Americans with really high activity levels could show higher TEE. Diet and calorie available probably affect the degree of compensation. pubmed.ncbi.nlm.nih.gov/41653928/

@davykevinp Good point! @HermanPontzer? I can always discuss this with John Speakman when I speak with him next week.

@MohammedAlo Yep - Hadza and other foragers and farmers have low cholesterol pubmed.ncbi.nlm.nih.gov/30511505/

@HermanPontzer can an actual anthropologist who studied this for 20+ years handle this?

@sweatscience @cremieuxrecueil Here’s the regression of compensation vs exercise load. Includes all data including resistance training (open symbols) w negative compensation, so it will underestimate aerobic

@sweatscience @cremieuxrecueil Whether it’s ~30 or ~50 (we report ~50 for aerobic interventions without diet) there’s clear compensation happening.

On @HermanPontzer energy compensation model: Per @sweatscience the figures are incorrect. "30% of your exercise energy are added to your metabolic expenditure" is a modelling error biased by low exercisers whose data isn't informative open.substack.com/pub/sweatscien… Thoughts? @cremieuxrecueil

@yzilber @sweatscience Not a modeling error, a cohort size weighted mean. If you don’t like that figure, you can use the 50% compensation for all aerobic interventions without diet, or the 100% comp with diet.

@anup_malani Here’s the latest update and review of the constrained model cell.com/current-biolog…

Pontzer et al. (2016): "Constrained Total Energy Expenditure and Metabolic Adaptation to Physical Activity in Adult Humans" pmc.ncbi.nlm.nih.gov/articles/PMC48… Pontzer et al. (2018): "Hunter-gatherers as models" pmc.ncbi.nlm.nih.gov/articles/PMC58… @HermanPontzer

Weight is not just calories in minus calories out. How much you eat matters, but you cannot exercise it away. Your body compensates. After a certain point, total daily expenditure plateaus no matter how active you are.

@KurtFWenning It does. Env explains between group diffs. Alleles (which are shared across pops and don’t segregate nicely by “race” which is a social category) doesnt explain these group diffs but can affect var within pops. I invite you to read Turkheimer or as I suggested, Adaptable. Cheers!

@HermanPontzer This doesn't follow from "env is more than income" and "white people committed genocides in the past". You didn't even bother to explain the black IQ and crime gap. Do you want to elaborate on the idea that most blacks are wrongfully incarcerated?

This kind of “race science” for grades or IQ is why everyone should read #Adaptable Group diffs on tests tell us nothing about underlying biology - but that’s how they’re used.

@KurtFWenning That there are no meaningful biological group differences with respect to behavior (or cognitive ability). The (no doubt 1000’s) of alleles involved are shared across pops, and env has a huge effect.

@HermanPontzer Ok so what does this tell us about using underlying biological differences to explain group differences?

@KurtFWenning White people literally conducted genocides / mass murder for several generations in a row. Arguably still doing it. Other groups have too. All humans are capable of it.

@HermanPontzer I'm not sure how this is relevant about biology. If white people were starting a genocide every other generation, you could make a point that whites are biologically wired to do that. But africans were not much different in the past.

@KurtFWenning People killing people only counts when it’s in the time and context that supports your view. Ok.

@HermanPontzer Red herring fallacy

@KurtFWenning Remind me which group killed more humans in the 1940’s? Whites, Japanese, or Blacks? How about people killed and land stolen in North America between 1500 and 1900?

@HermanPontzer Ok, let's look at homicides. All homicides are usually investigated, but the police can't know ahead of time whether someone was killed by a black or a white person. Yet, blacks are responsible for most homicides, independent of income.

@shtuka70 Why? I think they speak to group differences in resources, early learning, the culture around schooling. The “race” groups here aren’t even genetically coherent populations - real trouble for an honest hereditarian.

@HermanPontzer These data are easier for the hereditarian to accomodate, though.