It seems like there's a middle ground here, which is that there are innate propensities or drives that are then molded and directed by our cultures, in both healthy and unhealthy ways.

I mean, I don't trust the processed food industry either, and will readily admit that they do everything they can to manipulate human desires for profit. Do people have an innate desire for Coke and chicken nuggets? No. But looking at what the industry does, and then using that to conclude that (most) humans have no instinctual tendency towards sugar and high fat foods seems mistaken.