Ok atheists... explain this one why dont ya?

Stumped? Hardly. Naturally, humans (as well as most, if not all organisms) find fattier and more calorie-rich foods to be more attractive as, without our domestic animals, infrastructure, etc. these foods would be rare and harder to find. Consider this; in a region, here are many apple trees and plenty of apples. Apples are in good supply. An animal wanders into the area. This is uncommon. You kill it and eat it. The animal, or meat in general, an important source of proteins, etc. is more attractive to a person that has less of that. This has carried over to modernized life. Makes sense, don't you think? Also, scientific logic (If a required resource is in short supply, getting more is of priority.) And I'm agnostic, not atheistic.