I Didn't Evolve Under These Circumstances. Part 1: Food

It's struck me a lot recently how many problems we have because progress has outpaced our evolution. I've decided to write a few posts about these problems and hopefully do a final one about some of the possible solutions.

Perhaps the most classic example of this is found in the way we eat and use our food for energy. Human beings as far as we can tell were hunter gatherers for the vast majority of our evolutionary history. We ran, a lot, and a lot of that running was spent getting food. And since food was relatively scarce we also became very efficient at using the calories we consumed. In fact, anthropologists suspect one reason we may have evolved to stand upright is because it burns fewer calories than walking on all fours like other primates. We even evolved instincts to conserve our calories. If we weren't running to catch prey (or to avoid becoming prey) or a few other evolutionary essential functions we instinctively moved around as little as possible.

About 10,000 years ago humans began cultivating crops. While this may have created conflict with our evolved instincts almost immediately initially raising crops was labor intensive and crop yields relatively low. There is some evidence that humans did evolve some with this change-since people with ancestory coming from geographic regions with a longer history of agriculture tend to have less obesity problems than those who didn't-but the change was relatively modest. Regardless of one's ancestoral evolutionary heritage the leaps and bounds in agriculture that have led to explosive gains in food output have left almost all of us ill-fitted instinctively to stay healthy. Our insticts, evolved over eons of time with food scarcity-have led us to eat much more than we need for health and to be as sedentary as possible. On top of that we evolved cravings for foods that were relatively scarce or difficult to attain but that are essential in small quantities that are now readily accesible such that we overconsume them-like fat and salt.

It's interesting the remedies we've tried to come up with to solve this problem. One novel idea is exercise. In the movie Back To The Future III the character Doc Brown in a saddened stupor begins rambling about the future to a packed bar in the late 1800's. He tells them that in the future people will run for recreation. A man in the bar immediately pipes up with "Run for fun? What the hell kind of fun is that?" with the fellow townspeople laughing in agreement.

Indeed the idea of exercising for recreation or enjoyment is rather ridiculous through the lens of most people throughout human history. Exercise wasn't something they fit into their lives-it was something they did to stay alive. Consequently we aren't very good at motivating ourselves to do it as we were when not running meant starving to death or being eaten by a sabertooth tiger. We struggle to get ourselves moving because the urgency simply isn't there.

Likewise we are not very good rejecting food,particularly delicious foods that we crave. Again, having too much food was a problem that few if any of our ancient ancestors would have faced on a regular basis-while starvation was a constant possibility. In the rare event that a smorgasbord was made available to our ancestors the extra fat reserves kept by the body would almost certainly have been burned off in a time when food became relatively scarce.

As bad as we are at exercise our capacity to deprive ourselves of food is even more dismal. It seems over the course of time our bodies did evolve some neurological rewards for running. When we run endorphins are released giving us an improved sense of well-being. But with food depravation just the opposite occurs. While depriving ourself of food does have benefits to the function of many of our organs, neurologically we are punished for it. Cortisol, a stress hormone, is released when we fast or reduce our caloric intake. This made sense for our ancestors-since it probably motivated them to look for food immediately since the time from when they started looking for food and when they actually found it would have often been quite long. However for modern humans this creates havock-reducing calories leads to stress that often leads to increased food consumption which then relieves the stress but leaves us overweight.

So our evolutionary past has clearly put us at a disadvantage in the battle of the bulge.