A recently released study on human energy expenditure (“Hunter-Gatherer Energetics and Human Obesity,” Herman Pontzer et al.) has garnered some attention in the media. The reason for all the attention? The study debunks a commonly held belief that our obesity epidemic is in large part due to our decreased physical activity.
Up until now, we’ve all heard one of the main reasons we are fat, and getting fatter, is we move far less than our ancestors (namely the hunter-gatherers). Images of animal-skinned Neanderthals chasing wild game across miles, picking at the last berries on a bush, and scratching mere mouthfuls from the dirt pervade our minds. When compared to our cushy lifestyles of cube-farm offices, drive-thrus, and delivery pizza (don’t forget Roomba, clothes dryers, and telecommuting), we look downright slothful. When’s the last time you did more than tear open some plastic for a big ol’ piece of beef?
I too was bought into the notion of decreased, daily caloric expenditure as a primary contributor to our gluttonous predicament. I loved to compare the “cost” of food in the way-back to today by how many calories you had to spend to acquire it. It made perfect sense to me. Back in the day you probably had to expend a few hundred calories to get maybe 50 – or so I thought.
Based on Pontzer’s research, we all need to step back and re-evaluate our self-flagellating model of laziness. Those purposeful, insane workouts meant to compensate for our post-Agrarian lifestyles ain’t gonna help that much. According to Pontzer and his team, when comparing Western culture to Hunter-Gatherer culture, we burn about the same calories. Even more fun to notice is Westerners actually burn more calories if you look at the total (in the study, they compensated for fat/lean body mass). That’ right; factor in our girth and we burn more. More. Hunter-gatherer women in the study averaged about 1,877 calories/day. Western women? Try 2,347. Hunter-gatherer men averaged around 2,649, while western men racked up 3,053 calories/day. Physical activity calories burned across the two groups was about the same, regardless of culture/lifestyle.
So what’s the “so what?” of all this scientific-mumbo-jumbo? It means we are all eating too dang much. And I have to say, I actually felt vindicated when I read numbers like 1,800 and 2,600. My tirades against 1,800 calorie mega-burgers (for lunch) are justified.
And yes, you could argue the types of foods we eat are impacting hormonal systems, firing off genes heretofore dormant, pesticides, herbicides, and plastics are jacking us up. But I’m telling ya, the easiest answer here is we eat too much. Mocha-choca-lattes as “drinks,” burgers that could serve a family of four, “personal” pizzas that used to be called “medium,” and the eradication of “small” from most menus are among the overindulgent proof.
And before a few of you have a freak out, I’m not proposing tossing in the gym towel. Exercise, both moderate and vigorous, have numerous – NUMEROUS – health benefits. Just don’t go expecting the scale to start zinging down to pre-pubescent weights from a mere 60 minutes a week.
Wanna test me? Track everything you eat for a week. I mean everything. If it crosses your lips, write it down. Weigh it. Measure it. Add it all up. See how many calories you are taking in. Bet you’d have to exercise vigorously, non-stop, for a decade to undo the damage. Betcha.