Valid for what? You have no obligation to eat what your ancestors ate. Our ancestors certainly didn't, which is why they didn't eat like single-celled organisms. If what you are thinking were true, it would be true for them as well.

Not to mention the fact that your food has evolved as well.

I didn't say obligation. After reading here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4091895/

My question was an oversimplification.