From what I've read, fructose stimulates hunger (causing you to want to eat more of it) and is processed by the liver directly into stored fat. That is not what my question is about, because those both make sense to me from an evolutionary standpoint: the plant wants its fruits to be eaten and seeds spread, and the body wants to store extra energy during times of plenty (when fruits are in season) for later when times are scarce.
Why, exactly, is fructose hepatotoxic? Is it because we are consuming it in such great quantities, greater than we ever would have encountered in natural, wild fruit? Or is there some sort of evolutionary benefit to either us or the plant? Is it a chemical defense, like capsaicin? Just curious.