Why We Get Fat

I just posted a video about why we get fat. It results from cravings for high-calorie foods. These cravings were given to us by natural selection. They were an essential part of survival back in cave man days. Cravings made us eat every bit of food we could find. Our bodies then stored excess calories in the form of body fat. We would feast on food when it was briefly available, then live off of the stored calories in our body fat during times when food was not available—times of deprivation or famine.

Body fat is the safest way for us to store calories. The calories are safe from pests and mildew. And body fat has advantages other than just storing calories, which is its main function in natural selection. Visible accumulations of fat can make sexual characteristics more noticeable, and thus be favored by sexual selection as well. Also, since we walk upright on two legs, we also sit upright, and it is very nice to have a fat butt to sit on.

But today, our bodies are storing calories for a famine that never comes. There are more obese people than hungry people in the world today. Today, for our health, we have to deliberately do things for which our caveman ancestors had no choice. We must limit our calorie intake, and make sure many of those calories are in healthy food—that is, just about the only kinds of foods available to our evolutionary ancestors. We also need to make sure we get plenty of exercise, something our evolutionary ancestors had no choice about.

This is just one example of many in which modern medical problems are best understood in the light of our evolutionary history.