Hunter-gatherers most likely to be leaner than us due to differences in diet, not activity

Obesity is essentially unknown in populations that live a traditional ‘hunter-gatherer’ way of life. As is well recognised, it’s different in Westernised populations. Why? Well, one theory, at least, is that hunter-gatherers are much more active, and are burning off more calories than their Western counterparts, which affords them the ability to maintain health weights. It’s a plausible theory, but new research suggests it may well be utterly wrong too.

In a study published in the journal PLoS One here researchers measured the energy expenditure of the Hadza – a hunter-gatherer population living in northern Tanzania in East Africa [1]. The method of measuring energy expenditure in this study (doubly labelled water) is recognised as accurate. The total energy expenditure in a group of 30 Hadza was compared to that data from ‘Westerners’. The result? Once body weight was taken into account (bigger people tend to burn more calories), energy expenditure was essentially the same.

In other words, this evidence points away from differences in activity and energy expenditure as being a major explanation for why hunter-gatherer populations tend to be much lighter than those living a more Westernised existence.

If the evidence points away from energy expenditure, then it also probably more points towards energy intake as a or perhaps the major differentiating factor.

But I feel we’ve been here before, in that the evidence as a whole shows that if weight and fat loss are the goal, efforts in a dietary direction pays much more handsome dividends than exercise. This is not to decry activity and exercise: there are many benefits to be had from these endeavours, it’s just that significant weight loss is rarely one of them.

So, what it is about the diet of the Hadza that appears to make them resistant to obesity? Is it that they don’t eat that much, because of reduced food availability? Is it something to do with the quality of the diet, more than the quantity? Could a primal diet have hormonal and metabolic effects that help protect against obesity? Or is it a bit of both? Is it possible that, for instance, the type of food eaten in a primitive diet somehow protects against overeating by sating the appetite more fully and guarding against overeating?

There is some evidence which shows that opting for a primal diet naturally shaves an average of a few hundred calories off individuals’ intakes compared to when they are eating a more Western ‘Mediterranean’ diet [2].

How does this happen? I don’t know for certain, but there are at least a few ideas floating out there. Here’s a few:

  • Many sugary and starchy Western foods are destabilising for blood sugar levels, and may trigger false hunger and food cravings due to episodes of rapidly falling and/or low blood sugar levels. More primitive diets are more stabilising to blood sugar, and may be less prone to inducing false hunger as a result.
  • Primitive diets may offer relatively more protein than Western diets, and protein has been found to offer more appetite-sating potential than fat or carbohydrate.
  • Some hunger and food seeking behaviour may be the result of relative deficiencies in key brain chemicals including serotonin and endorphins. Brain chemicals such as these are made from amino acids, and a protein-rich diet may help counter these imbalance by helping to optimise amino acid and brain chemical levels. These and other issues are explored comprehensively in the recently-updated The Diet Cure by Julia Ross.
  • Primitive and primal diets are generally devoid of ‘rewarding’ foods that can drive overeating. The theory that food reward is a major driver of obesity has been popularised by Dr Stephan Guyenet over at A primitive diet will also be devoid of foods that have been deliberately crafted to be rewarding and moreish.

Untangling what it is about diets made up of natural unprocessed foods make them, for most people, inherently more satisfying may take some time, if it happens at all. More important, I think, is the fact that I’ve seen many individuals lose considerable quantities of weight and maintain that loss as a result of adopting a diet which is inherently satisfying and does not require having to put up with undue hunger.

I’ve seen, time and again, how eating the right sort of diet helps control the appetite and makes it easy to eat the right sort of diet. My overwhelming experience is that when someone changes what they eat in an effort to lose weight, the less hungry they are the more weight they lose and the easier they tend to find it to maintain that loss. My experience is also that eating a more ‘primal’ diet is an extremely powerful tool here.


1. Pontzer H, et al. Hunter-Gatherer Energetics and Human Obesity. PLoS ONE 7(7): e40503. doi:10.1371/journal.pone.0040503

2. Jonsson T, et al. A Paleolithic diet is more satiating per calorie than a Mediterranean-like diet in individuals with ischemic heart disease. Nutr Metab (Lond) 2010;30(7):85

21 Responses to Hunter-gatherers most likely to be leaner than us due to differences in diet, not activity

  1. Graham 26 July 2012 at 8:01 pm #

    This fits well with what everyone who has lost lots of weight knows…it’s 90% diet.

    You can lose weight without working out, but you can’t outwork a bad diet.

  2. John Walker 27 July 2012 at 6:42 pm #

    I never felt that exercise was of any real use in making me slim, keeping me slim, or in keeping me fit. Perhaps the vascular system is most affected by exercise, and aerobics will give stamina, regulate blood pressure and recovery heart-rate. But that’s about it. All the exercise I did as a youth (And I did a lot) has left me with ruined knees, (One replaced, and awaiting a bed-space for the other to be done.) Unless advances in growing new cartilage speed up apace!
    All things being equal, that is the worst of my problems, and as my weight comes down, my need for pills and potions diminishes. So it ain’t how much you eat, and how much you do, but WHAT you eat that counts. I am convinced.

  3. Aidan 27 July 2012 at 6:48 pm #

    As rigorous studies go, would you class this as poor or terrible?

    Let’s see, n= 30, 17 women with no statistical significance in PAL vs western women. So now n=13 for a non intervention trial.

    Then let’s take note of the average BMI of just over 25 in the Western population, so not an obese population, and depending on fat distribution, not an ‘overweight population’ either. Sorry what are we actually comparing in this study?

    And, lastly where in this study does it describe the calorie intake of the Hunter Gatherers? Perhaps it does, I just cannot find it. What I do see, is a small population bordering on underweight status. So most likely they have low caloric intake. And, what does low caloric intake i.e. dieting do, it lowers total energy expenditure (hence the flaw in dieting). So are we surprised with these inconsequential findings?

    As a low carb advocate for health, I ask: let’s not shoot ourselves in the foot by reporting bad science in an attempt to sell the low carbohydrate diet as the solution to all our woes, and in the end only garner the reputation of snake oil. Overzealouness will be the downfall if we report any science with no merit given to the real weight it carries.


  4. Dr John Briffa 27 July 2012 at 7:11 pm #


    Whatever deficiencies this study may have, its findings are consistent existing evidence that:

    1. diet, rather than activity, is the major determinant of weight (fatness)

    2. primitive diets appear to be better for weight control, at least in part because they’re generally more satisfying

    What I’ve tried to do here is put this new study in this context.

  5. hilda glickman 27 July 2012 at 7:26 pm #

    The other good thing about primitive diets is that they are richer in nutrients. In the West we do not eat the nutrients needed to produce energy and get energy from food. Much modern ‘food’ is just like polyfilla.

  6. Aidan 27 July 2012 at 7:43 pm #

    Hi John,

    You say the study is consistent with point 1, as though it is a given, but really this evidence for a population wide recommendation is equivocal.

    The recent physical activity series from the Lancet shows how sedentary our lifestyles have become. Accelerometer data, shows in these surveys people likely inflate the results i.e. the shocking results reported actually flattered a truth. Are we really to accept that this has no impact on our calorie expenditure, and use this anecdotal at best study as evidence?

    An analysis of the National weight Registry in the US shows physical activity to be a major determinant in not only weight loss success, but in keeping the weight off. This is in agreement with what we now know: that caloric induced weight creates an over-compensatory decrease in non resting energy expenditure.

    Literature shows the studies, in which physical activity was an inferior or ineffective weight loss agent, simply prescribed too low an activity amount/intensity. People may not like to hear it, but your body was abused for years, a leisurely walk of 30mins a day is not going to cut it. Studies which use a proper intervention such as ‘walk fast, walk often’ are proven in clinical studies as effective.

    And anecdotally (so for whatever it is worth) I have yet to have a person who has not lost weight through exercise .

    Point 2. you get no argument here that such diets are far superior to the processed, sugar laden diets which define our current way of eating


  7. Debra 27 July 2012 at 8:34 pm #

    Interesting because just before leaving work this morning I was reading an article about a man that is 61 and not missed a day of running, average an hour a day (sometimes more, sometimes less) since high school, and yet he said he has to really watch, has had a tendency to gain weight in the last few years….and he runs every single day, so exercise is NOT the issue in his case. Instead he has to watch what he eats.

  8. Polly 27 July 2012 at 9:19 pm #

    I often wonder what effect sensory issues play in weight gain. I often find that even though I am not hungry… I crave some thing sweet or crunchy or salty.

  9. Stephanie 27 July 2012 at 10:54 pm #

    As someone who has lost over 100 pounds and has kept 95 pounds off for 1 1/2 years, I can confidently say diet is the primary reason. Stress causing, high intensity workouts tended to make me hungry, but long (1 hour) walks, reduced stress and made it easier. The intense work outs worked against me. I’m still overweight and would like to lose another 30 pounds, I’m pre-diabetic, and found that insulin resistance was the main cause of the weight gain. Although protein/fats have helped to keep the weight off, along with plenty of green vegetables, I still struggle with cravings. Stress caused by life can only be aggravated by intense workouts, raises my blood sugar, then when it drops again, I’m hungrier than before I started. The quality of the proteins today, compared with hunter/gatherers should be mentioned, since I primarily rely on corn fed beef and chicken. I wish I had more access to venison, but even then aren’t they eating primarily crops except when acorns are available? My experiments with what works for me has only led me to the confidence that highly processed anything is bad, (not to mention my liver was severely affected, but is now much better) but highly process sugary and starchy foods will eventually lead even the most blessed metabolism into resistance as they age. I’ve had a weight problem all my life, and have been on a perpetual diet journey for most of it. The answer is too complicated for a ‘one diet fits all’ recommendation. But I’m confident anyone will see improvement by severely cutting sugary and starchy foods from their diet. Especially the artificial food primary pushed from the food industry today. This information only confirms what I have recognized myself, intense workouts will not result in significant weight loss and can sometimes cause things to get worse because the body is put into a ‘stress’ mode eventually causing more weight gain when the activity is reduced.

  10. Ani 27 July 2012 at 11:48 pm #

    I agree with you Hilda, primitive diets do tend to be more nutrient dense. A nutrient dense diet can impact hunger levels : Joel Fuhrman J et al. 2010. Changing perceptions of hunger on a high nutrient density diet. Nutrition Journal 2010, 9:51doi:10.1186/1475-2891-9-51. Published 7th November 2010. The study authors conclude: “A high micronutrient density diet mitigates the unpleasant aspects of the experience of hunger even though it is lower in calories. Hunger is one of the major impediments to successful weight loss. Our findings suggest that it is not simply the caloric content, but more importantly, the micronutrient density of a diet that influences the experience of hunger. It appears that a high nutrient density diet, after an initial phase of adjustment during which a person experiences “toxic hunger” due to withdrawal from pro-inflammatory foods, can result in a sustainable eating pattern that leads to weight loss and improved health. A high nutrient density diet provides benefits for long-term health as well as weight loss. Because our findings have important implications in the global effort to control rates of obesity and related chronic diseases, further studies are needed to confirm these preliminary results”.

    Often popular weight loss diets provide low levels of micronutrients : Christopher D Gardner CD et al. 2010. Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study. Am J Clin Nutr. E-Pub doi:10.3945/ajcn.2010.29468

    Certainly in my work with women who have emotional eating issues I find that a high nutrient density diet is really helpful (I believe this to be, in part, due to the positive impacts on mood).

    Another great post John, thanks!

  11. Sherry 28 July 2012 at 12:31 am #

    It seems obvious to me that if we Westeners only ate what we could catch or dig up we would be a lot thinner and fitter. Other than that, I`m not terribly sure what this study proves. You say they ate a Primitive Diet, but exactly what does that entail?The study does mention they ate a lot of honey, so that does rather throw a bit of a cog in the theory of low carb eating! If it was high in protein, someone in the tribe must have done a fair bit of hunting unless the game just wanders into the village and waits around to be turned into chops. “Gathering “or cultivating plants must also involve a fair bit of action one way or another. That`s just the energy expended getting the food,let alone whatever else needs to be done. Just because bigger people use more energy getting off the couch and driving to the supermarket…..? It hardly compares,does it? I`m sure if I`m missing something here, you`ll set me straight.

  12. kate 28 July 2012 at 12:54 am #

    My two role models for the impact of exercise on health are 1) the man who rode his bike several miles to the train station every day before boarding the train to go to work, in his business suit! He was in his mid-60s. 2) my boss, who was in his mid 40’s and ran to work in shorts and tee, about 10 miles, every day, and changed into a business suit in the restroom.

    Consider that each had to return home at night, the same way they came from home. In inclement weather. My boss ran in marathons. The other man simply looked good for his age. But in both cases, they ‘ate whatever they wanted, as much as they wanted, whenever they wanted.’ At that point, diet simply didn’t matter as much as staying on track with bike and jogging shoes.

    Definitely not for everyone, but inspiring.

  13. Dr John Briffa 28 July 2012 at 1:08 am #


    Other than that, I`m not terribly sure what this study proves.

    The study doesn’t prove anything. It has, however, provided some data that challenges the idea that differences in ‘adiposity’ between ‘primitive’ and ‘Western’ populations are down to differences in energy expenditure, and points towards diet as the major differentiating factor.

    The energy expended during the gathering or foods (and other related tasks) and how this compares to more sedentary existences is essentially irrelevant here: the fact is, once body weight is taken into consideration, the Hadza don’t burn more calories than typical Westerners.

  14. Dr John Briffa 28 July 2012 at 1:20 am #


    Good for them (genuinely). Unfortunately, we have no idea whether these men’s exercise habits contributed in a significant way to their weight control. They may, for example, both be naturally thin, not prone to weight gain, and could ‘eat whatever they liked’ irrespective of their exercise habits.

    Plus, I (like others) have know many people who have found that regular exercise simply does not help their weight loss efforts in a meaningful way, and also the evidence in this area supports this. I’m not decrying exercise, and neither do I deny that some may benefit in terms of weight loss. On the whole, though, exercise is not a particularly efficient or effective way to regulate weight, and dietary efforts normally pay more handsome dividends here.

  15. Steve Pretty 28 July 2012 at 8:56 pm #

    I read this article. Very interesting. I do feel it is important to note what the authors have to say in their discussion:

    It is important to note that this was not an intervention study; we examined habitual TEE, PAL,
    and body composition in hunter-gatherers and Westerners, but did not examine the effects of imposing increased physical activity on Westerners. Physical activity has important, positive effects on health
    [39], and increased physical activity has been shown to play an important role in weight loss and weight-maintenance programs [40].

  16. Steve Pretty 28 July 2012 at 9:38 pm #

    Further to my previous comment, the reference in the article (shown as [40], from the Journal of Obesity) is available on line. It is a review article, which concludes:

    The vast majority of scientific evidence supports a beneficial role of exercise on achieving body weight stability and overall health.

  17. Helen Howes 29 July 2012 at 5:00 pm #

    Have you considered the correlative idea – that thin people with excess energy may be more inclined to exercise, and therefore give the impression that the exercise leads to the thin-ness?
    I was a Fat Fit Kung-fu Instructor for years – no amount of running, jumping, and kicking-people-under-the-chin made any odds to my weight.

    When I altered my diet, I got thin(ner) very fast (25 kilos in 3 months), down to my “ideal” weight. I then adjusted the diet a little and stabilised..

    After 7 years, I’m still where I stopped. However, in the meantime, my arthritises (3 sorts) and assorted other physical problems have almost completely removed my ability to move at any pace or for any length of time.. I have a Broken Metabolism, sure, but I can’t see how I could fix it with Eatlessmovemore, when the the proper solution appears to be Eat Right, Move as much as you can..

    I love my bike, but cannot ride at present.. Last time I weighed myself I was 200g heavier than my ideal (not statistically significant)

    I’m never unsatisfiedly hungry, eat High Fat Low Carb Moderate Protein, and get to have heavy cream on my breakfast..

    It’s a Hard Life


  18. PhilT 29 July 2012 at 5:05 pm #

    The daily energy expenditure range of the Hadza women at average 20 BMI and 43 kg was entirely within the range of energy expenditures for western women at average 27.5 BMI and 74 kg but the average of the former was 500 less. So we can’t argue that Western women are fat because they expend less energy, which I think is the key point – they expend *more* energy on average (despite being a bit less active).

  19. Megan 30 July 2012 at 11:32 pm #

    When thinking about the differences in exercise levels and weight, I always compare myself and my husband. He has a very physically active job and eats in excess of 3000 cals a day (mostly sugar and carb based to keep up his energy – so he says) and is very slim. Prior to changing jobs he was desk bound and still the same weight he is now. No exercise at all but he ate much less.
    I survived on less than 1500 cals for years and lost little weight despite regular workouts and walking.
    I changed to low carb and lost 50 pounds and yet I stopped exercising other than walking.
    My point is that if lots of carbs are being consumed, it is essential to work them off or you will put on fat. However if you cut those carbs, you can be as lazy as you like and still lose weight. I know what path most of us will take.
    Those of us with “broken” metabolisms have to take the low carb route because no amount of exercise will ever allow us to eat the carbs consumed in the average diet.

  20. Barb 1 August 2012 at 10:45 pm #

    I am also wondering if other factors are at play here. For instance, in western society, a large percentage of us are exposed to the following things almost from birth: processed formulas, (some containing soy), vaccinations, antibiotics, other medications, processed food, polluted air, treated water, light pollution, cosmetics made with chemical ingredients (starting with our Johnson’s Baby lotion and No More Tears shampoo), noise pollution, sunscreen, pesticides, fungicides, CAFO meats and eggs, dental work such as amalgam fillings and root canals, EMF radiation, X-Rays, toxic fumes from our clothing, draperies and carpets… etc, etc, etc.

    I am a 44 year old woman, not in menopause. I have been paleo for about 2 years now. With or without exercise, I remain obese. I have tried various caloric amounts. I have tried intermittent fasting as well as a ketogenic paleo diet. Nothing works.

    I am in good health, and show no issues with blood glucose, or hormone issues (as far as the tests can be trusted. A salivary cortisol shows that all is normal there. So my n=1 experiment is leaning towards the idea that there has to be more than meets the eye, even in this study.

  21. Pete Grist 8 August 2012 at 3:55 pm #

    All pretty tenuous. A more obvious explanation is that they just don’t have as much food available, so don’t eat as much as we might. The recent Horizon programme suggest that going hungry for two days (600 cals) a week is all you need…..

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