Why do we ignore human evolution when it suits us?

In recent years, I’ve written a few health science pieces, including pieces on body weight and body image. For example, ”Pudging the Truth“.

One widely advertised public nostrum that I came to question was the idea that being overweight* was a serious cause of health problems. The evidence seems to show that lack of exercise, often associated with overweight, is a bigger problem. Fat active people typically did not enjoy worse health than thin active ones. Public angst over weight loss relates to body image problems, fuelled no doubt by a huge diet industry.

Now, what does this have to do with human evolution?

Let’s assume humans evolved. Well, here are two scenarios to choose from:

1. Humans evolved in such a way that carrying even a little extra weight would be bad for our health.

2. Humans evolved in such a way that carrying a little extra weight would not be bad for our health. The weight might come in handy in times of hunger or disease.

The second seems far more likely to me.

Now, here are two other scenarios:

1. Humans evolved in such a way that lots of exercise is good for us.

2. Humans evolved in such a way that lots of exercise is bad for us.

Again, based on ancient lifestyles, I’d certainly pick #1 and I’d be right.

So you could have made a prediction about the best supported health evidence just by assuming that humans evolved.

Yet very few people seem to have done so. When reasonable conclusions from human evolution contradict the obsessions of the Lose-Weight-Fast cover stories, who wins? Don’t even ask.

Popular theorizing from human evolution seems instead to feature a lot of bizarre stuff instead.

But you know, come to think of it, a special creationist could draw the same inferences from the evidence. If you were designing a human being, you would build in some tolerance of a few extra kilograms, wouldn’t you? So in neither case should we have come to the conclusion that popular culture actually endorses.

Maybe the idea of human evolution functions for a lot of people as Apes ‘r Us! That is, it is a cultural icon. And perhaps a way we forgive ourselves for what we know we should be ashamed of.

(*Here I am not discussing clinical obesity - I mean being overweight according to standard height and weight tables but not obese.)