Imagine a coffee-skinned African woman living the simple life of a gatherer on the northern plains of Tanzania.
During the day she is constantly active — walking kilometres away from home, gathering berries and roots, and carrying her heavy load back to the village. She is fit. She has to be, her very survival depends on it.
Her lifestyle is far removed from the Western world where a woman jumps in the car and drives over to the nearest Coles to buy a few groceries for dinner. In contrast to African women, Western women live a sedentary existence.
So who has the highest Total Energy Expenditure (TEE) in a day? Who is burning the most calories?
Hunter-Gatherer Energetics and Human Obesity
A recent study1 published last month, set out to answer this question by monitoring and recording the activity level of the Hadza tribe of hunter-gatherers.
In this study, we examined daily energy expenditure and physical activity level in Hadza foragers to test the hypothesis that hunter-gatherers expend more energy each day than subjects in market and farming economies.
Their results were surprising, shattering previously held beliefs about exercise and weight loss.
The hunter-gatherers of Tanzania have the same total energy expenditure per day as Westerners. In other words, even though they were highly active, they didn’t burn any more calories.
Measurements of TEE among Hadza hunter-gatherers challenge the view that Western lifestyles result in abnormally low energy expenditure, and that decreased energy expenditure is a primary cause of obesity in developed countries. Despite high Personal Activity Level (PAL) and dependence on wild foods, Hadza TEE was similar to Westerners and others in market economies.
It seems the body has a mechanism to regulate your metabolism to a set point whether you’re running a marathon or writing a novel. It doesn’t matter how much exercise you do, in the end your body will adapt and return to ‘normal’ amounts of energy expenditure.
The similarity in TEE among Hadza hunter-gatherers and Westerners suggests that even dramatic differences in lifestyle may have a negligible effect on TEE, and is consistent with the view that differences in obesity prevalence between populations result primarily from differences in energy INTAKE rather than EXPENDITURE.
I’m not suggesting exercise isn’t good for you. It is good for your organs, circulation, bones, strength, joints and psychological health. But it’s a myth that going to the gym or heading out for a run will neutralise those calories in the cupcake you just ate.
“Move more” is no longer part of the weight loss equation.
Move because you love your body, move because it clears your head, but don’t worry about moving if you’re expecting to see a smaller number on the scales.
——————
- Pontzer H, Raichlen DA, Wood BM, Mabulla AZP, Racette SB, et al. (2012) Hunter-Gatherer Energetics and Human Obesity. PLoS ONE 7(7): e40503. doi:10.1371/journal.pone.0040503 ↩
I sort of can’t agree because I think I am living proof of exactly the opposite – I’ve just crossed over the -50kg mark in my weight loss journey and whilst I credit most of it to simply eating well and not nearly as much as I had been, I know for a fact that without exercise I wouldn’t have come so far. My best weight loss results have come from a week of steady (not gut-busting but definitely ache-worthy the next day) exercise that’s outside of the normal incidental stuff I do.
So… happy for someone to explain how else it’s working, unless what I am doing is kick-starting my metabolism back into gear. I think that comparing a naturally (and by necessity fit) woman from a completely different culture and environment to an admittedly lazy western woman with access to all the mod cons is like comparing the proverbial fruit, to be honest.
Great article. It did give me something to think about. 🙂
Congratulations on your weight loss Ren — if you’re enjoying your exercise then please don’t stop.
Without knowing your exercise routine or history, I’m guessing that ‘a week of steady exercise’ is not what you do week in and week out so your body hasn’t adapted to it yet. Anything non-routine will spark a boost in energy expenditure but I don’t think it is sustainable.
There are also other factors the might be responsible for the boost exercise gives your weight loss — your belief that you’ll lose more if you exercise, the greater connection you have with your body, a greater connection with nature (if you’re outside), a more positive outlook from exercise endorphins (letting go of your emotional baggage) and your improved self-esteem/self-love from liking what you see in the mirror.
Thanks for taking the time to add your voice to the conversation x
i was going to try to run this morning. i think i may just walk instead : )
Brilliant ♥
Awesome article! The study is very interesting but the results are rather counter-intuitive. Our bodies cannot make energy out of thin air so more activity must lead to more calories burned, unless the bodies of hunter-gatherers of Tanzania behave differently due to genetic differences. Here’s another very interesting study showing that genetics is a much more important determinant of body weight than a lifestyle –> http://youtu.be/_6-A0iHSdcA
Thanks for your comment Yevgeniy.
Interesting! I think though that exercise is still important for weight loss because it helps people regulate their appetite and also helps our bodies deal with the higher sugar diets that Westerners tend to eat. The study needs to be looked at critically, in context. For example, if the tanzanians stop exercising so much, what happens? I doubt their TEE would stay the same, even after years of doing it. Look at what happens to retired athletes. It’s a very interesting study, but the interpretation of it isn’t completely straighforward. For example, these people don’t have the metabolic problems that arise from a westernised diet. I agree though, that diet is mainly responsible for what body composition you are currently at. What is that saying? ‘You can’t out-exercise a bad diet’.
Thanks Sara for your critique. I agree things are always more complex than they first appear.