Biology of Bingeing, Part I

If you have seen the documentary “March of the Penguins” then you have seen why gorging on huge quantities of food has historically been a valuable habit for survival.

In the movie we see that each year the Emperor Penguins walk (with very small clumsy steps!) over 70 miles to their breeding ground, where they will court and mate. After laying an egg, the female will walk back 70 miles to the ocean to feed while the male stays behind to incubate the egg, trying to keep himself and the egg warm for 4 months of frigid cold and Antarctic storms. He can’t eat during that time and is near starvation by the time the baby penguin hatches. If all goes well, the mother returns with a belly full of food to share with the chick and the male walks back 70 miles (nearly starved) to the ocean to refill his belly. If the mother shows up too late, the chick will starve or the father will be forced to return to the ocean (leaving the chick to die) because he needs to eat or he will die.

Starvation is constantly a threat.

Now try to imagine a penguin who, during her brief feeding opportunity says “Goodness, I think I’m satisfied on a small quantity and I don’t want to stuff myself.” There probably have been such penguins. And they get weeded out of the gene pool very quickly! Only the ones that stuff themselves silly have enough food to survive the long walks and hard living until they will have their next feeding opportunity.

This is one example of why animals are programmed to overeat. Our ancient biology doesn’t know that food is plentiful and life is easy. I like to remind myself that rather than feeling guilty about wanting to overeat, I should feel lucky that my ancestors did so, because that’s likely the reason my genes survived this long.

Overeating is natural, so we shouldn’t feel guilty–but that doesn’t mean we shouldn’t use smart strategies for avoiding it. I’ll write more about that tomorrow. In the meantime, let your conscience be clear about overeating and blame your biology.