What species are you including in mankind? Cause homo sapiens (sapiens) haven't been around nearly that long...

"Natural" food is not necessarily good. "Unnatural" food is not necessarily bad.

https://en.wikipedia.org/wiki/Appeal_to_nature

Well, mankind didn't use medicine for around a million years. Then after using herbal medicines for around 10,000 years, we've only been using antibiotics during the last century. So the "hipster fad" is actually the using of medicine. It's not a natural thing for mankind to be doing.

Well, mankind practiced almost universal cannibalism for around a million years [note: this is true]. Then after restricting cannibalism to certain tribes and certain occasions for around 10,000 years, we've only ceased cannibalism entirely during the last century. So the "hipster fad" is actually the lack of cannibalism. It's not a natural thing for mankind to not be consuming the brains of its vanquished enemies.

Wash, rinse, and repeat.