Eli5:What prevents our bodies to get rid of excess food/calories that are not necessary, and instead turns it into fat?

Question

Eli5:What prevents our bodies to get rid of excess food/calories that are not necessary, and instead turns it into fat?

In: 55

Answer 1

Millions of years of evolution where we never knew when/if our next meal would be coming, versus the last 3/4 of a century or so where sugar-laden fruits are easily accessible year-round and eating a pound of fatty meat at every meal is just one quick stop at the supermarket away.

Our bodies simply weren’t built to eat this way this much, and evolution is a sllooowwww process.