Humans are “lazy overeaters”
The following is my response to a post on another blog about why people crave bad foods. It references something Arthur DeVany said on his Evolutionary Fitness blog about humans evolving to be “lazy overeaters”, which I agree with:
Arthur DeVany suggested a big part of the reason for overeating is that we evolved to be “lazy overeaters”, which makes perfect sense in a pre-agricultural environment, where calories are scarce and require effort to obtain. For 250,000 years or so, our human ancestors (or a few millions of years if we include our pre-human ancestors going back to the australopithecines) had to forage or hunt for food, and when they found some had to eat what they could, not being certain of when they’d find or kill their next meal. There was no McDonald’s around the corner, no fridges full of hot pockets. In such an environment, it makes perfect sense to conserve energy (be “lazy”) and eat as much as you can when you find it.
The environment has changed dramatically, but from a genetic standpoint we haven’t, and over the past few decades, the effort required to obtain high calorie foods has continued to decrease. It is no longer necessary to spend time baking cookies or cakes or preparing big meals from scratch, which may have been a deterrent to overeating for some. If you wanted a slice of cake or a pizza you had to make it yourself.
The food industry has made it possible to now obtain massive amounts of calories with barely any effort, so being a “lazy overeater” is now a threat to one’s health rather than a necessity for survival.
I imagine if we turned the clock back only a few decades and got rid of the majority of packaged foods, fast-food restaurants and delivery services and convenience stores so people had to at least spend some time and effort making their own food, there would be far fewer obese people, since they wouldn’t have the ability to stuff their faces on a whim.
Evolutionary biologist Theodosius Dobzhansky wrote an essay titled “Nothing in biology makes sense except in the light of evolution”, and since exercise and nutrition are biological sciences, the same could be said for them. While I don’t agree with all of Art DeVany’s exercise recommendations, I believe his thinking on exercise and nutrition, as well as Loren Cordain’s writings on the paleolithic diet, are a big step in the right direction.
As for having evolved to be lazy overeaters, this does not mean humans are doomed to be fat, slow and weak as so many of our population have become, because we evolved something else – a highly developed ability to reason. We are not controlled by instinct. Influenced, perhaps, but not controlled. We have the ability to consider the consequences of our actions and whether they are consistent with our values and to act accordingly. If we value being strong, fit and lean we can choose not to do things which would result in consequences inconsistent with those values, like overeating and being lazy. We can choose to eat a healthy diet, we can choose to be active and to exercise intelligently. We are not slaves to our whims and impulses. Unlike animals, we are capable of self-discipline.
So while biology may predispose us to the kind of behaviors that have contributed to the current epidemic of obesity, it is not an excuse. The choice is yours.