Monday, December 24, 2012
Debunking the Hunter Gatherer Workout
The interesting take home is that the hunter gatherers were all thin while effectively been more sedentary than we ever are. The difference of course is in the quality of the carbohydrates and in the application of short bursts of exertion.
More seriously though we need to respect sedentary protocols and obviously practice racket ball. Distance running has its own merits but is is hardly the only way to physically prosper.
This is a surprise to those of us who ever thought that our ancestors entered a life of unrelenting toil because it has more rewarding and it allows us to understand the reluctance of hunter gatherers to adopt modernism. If your family has not gone hungry for little effort for thousands of years, it is hard to merit a change.
It is also noteworthy that 80 year old grandmothers remain strong and vital.
Al Sears, MD
December 14, 2012
I’m blessed to have been in Tanzania three times now. I was lucky enough to meet with the Masai, the ancient hunter-gatherers who shared with me all of their herbal knowledge.
I was also blessed to be able to visit the Ngorongoro Crater and get a personal tour from the chief conservator of the crater. He told me the inside story of how they take care of the biggest lions on the planet.
And I also went to see Olduvai Gorge, the birthplace of humankind. It’s one of the most important archeological sites in the world, where the archeologist Mary Leakey discovered almost 2-million-year-old australopithecine pre-human remains.
It’s amazing one country has all those things in it... and now I’m making plans to go back there to visit another ancient tribe of hunter-gatherers.
Because after reading a recent article in The New York Times, I’m definitely planning on seeing the Hadza people.
At the time I read the article, I was reading the latest research on exertion and oxygen uptake for my new subscription newsletter Confidential Cures.
I read a study called “Hunter-Gatherer Energetics and Human Obesity” and noticed that the lead author had written an article in The Times. His article is titled “Debunking the Hunter-Gatherer Workout.”
The gist of it is that the author and his colleagues wanted to try and figure out if a lack of physical activity is the reason that modern human beings are fat. So they decided to measure calories burned in a hunter-gatherer group in Africa and compare it to our calories burned.
They looked at the Hadza from northern Tanzania, a group pretty much untouched by the West, which is very rare in the modern world. And they found that the Hadza didn’t burn more calories than we do.1
I’ve visited many of these tribes myself, including the Batwa and the Masai in Africa, and the Ashaninkas in South America. And it’s not surprising that they don’t burn that many calories...
They don’t hunt that often. We push ourselves at a low level of exertion all day long every day because of our busy lifestyle. They sit back and pretty much lie around most of the time.
The lead author went on to write in The Times that, because we burn the same amount of calories, we are not fat due to being sedentary... and that this debunks the hunter-gatherer style workout.2
But what they studied has nothing to do with proving why people are fat. The researchers never looked at the quality of the Hadza’s exertion, or the intensity of it, or even what kind of exertion it was... which makes all the difference.
What they should have done was open their eyes and look around and see that the Hadza were all thin. And being thin is not about burning calories. It’s about the kind of calories you take in, and the way you exert yourself.
Compared to how hunter-gatherers ate, we more than doubled the percentage of carbohydrates that we consume. Plus, the character of the carbohydrate has changed to a much higher glycemic index.
Your body converts carbs into either sugar or fat. So if you religiously follow the latest low-fat, high-carb diet, your waistline will only get bigger.
And the modern notion of constant, low-level endurance exercise to get in “the fat-burning zone” makes it worse. Exertion for short periods and a total of less than 20 minutes, like I show you how to do in my P.A.C.E. program, will use these carbs during exercise and signal your body that you don’t need fat. You burn off the fat after your workout while you replenish the carbs for your muscles.
Debunking the Hunter-Gatherer Workout
By HERMAN PONTZER
Published: August 24, 2012
DARWIN isn’t required reading for public health officials, but he should be. One reason that heart disease, diabetes and obesity have reached epidemic levels in the developed world is that our modern way of life is radically different from the hunter-gatherer environments in which our bodies evolved. But which modern changes are causing the most harm?
Many in public health believe that a major culprit is our sedentary lifestyle. Faced with relatively few physical demands today, our bodies burn fewer calories than they evolved to consume — and those unspent calories pile up over time as fat. The World Health Organization, in discussing the root causes of obesity, has cited a “decrease in physical activity due to the increasingly sedentary nature of many forms of work, changing modes of transportation and increasing urbanization.”
This is a nice theory. But is it true? To find out, my colleagues and I recently measured daily energy expenditure among the Hadza people of Tanzania, one of the few remaining populations of traditional hunter-gatherers. Would the Hadza, whose basic way of life is so similar to that of our distant ancestors, expend more energy than we do?
Our findings, published last month in the journal PLoS ONE, indicate that they don’t, suggesting that inactivity is not the source of modern obesity.
Previous attempts to quantify daily energy expenditure among hunter-gatherers have relied entirely on estimation. By contrast, our study used a technique that calculates the body’s rate of carbon dioxide production — and hence the calories burned per day — by tracking the depletion of two isotopes (deuterium and oxygen-18) in an individual’s urine over a two-week period.
It was a testament to the Hadza’s graciousness, and their years of friendship with several of my colleagues, that they welcomed us into their camps and participated in the study. As we sat back and observed, the Hadza went about their normal routines.
The Hadza live in simple grass huts in the middle of a dry East African savanna. They have no guns, vehicles, crops or livestock. Each day the women comb miles of hilly terrain, foraging for tubers, berries and other wild plant foods, often while carrying infants, firewood and water. Men set out alone most days to collect honey or hunt for game using handmade bows and poison-tipped arrows, often covering 15 to 20 miles.
We found that despite all this physical activity, the number of calories that the Hadza burned per day was indistinguishable from that of typical adults in Europe and the United States. We ran a number of statistical tests, accounting for body mass, lean body mass, age, sex and fat mass, and still found no difference in daily energy expenditure between the Hadza and their Western counterparts.
How can the Hadza be more active than we are without burning more calories? It’s not that their bodies are more efficient, allowing them to do more with less: separate measurements showed that the Hadza burn just as many calories while walking or resting as Westerners do.
We think that the Hadzas’ bodies have adjusted to the higher activity levels required for hunting and gathering by spending less energy elsewhere. Even for very active people, physical activity accounts for only a small portion of daily energy expenditure; most energy is spent behind the scenes on the myriad unseen tasks that keep our cells humming and our support systems working. If the Hadza’s bodies somehow manage to spend less energy in those areas, they could easily accommodate the elevated energy demands of hunting and gathering. And indeed, studies reporting differences in metabolic-hormone profiles between traditional and Western populations support this idea (though more work is needed).
Our findings add to a growing body of evidence suggesting that energy expenditure is consistent across a broad range of lifestyles and cultures. Of course, if we push our bodies hard enough, we can increase our energy expenditure, at least in the short term. But our bodies are complex, dynamic machines, shaped over millions of years of evolution in environments where resources were usually limited; our bodies adapt to our daily routines and find ways to keep overall energy expenditure in check.
All of this means that if we want to end obesity, we need to focus on our diet and reduce the number of calories we eat, particularly the sugars our primate brains have evolved to love. We’re getting fat because we eat too much, not because we’re sedentary. Physical activity is very important for maintaining physical and mental health, but we aren’t going to Jazzercise our way out of the obesity epidemic.
We have a lot more to learn from groups like the Hadza, among whom obesity and heart disease are unheard of and 80-year-old grandmothers are strong and vital. Finding new approaches to public health problems will require further research into other cultures and our evolutionary past.
Herman Pontzer is an assistant professor of anthropology at Hunter College and a co-founder of the Hadza Fund, a nonprofit organization that supports the Hadza population.