[HyperSane]

" It would be pretty disadvantageous for animals to have no regulation on their fat growth in times of abundance. Something more has to go wrong to cross the line from "saving for a rainy day" to "killing you". ""

I really can't blame you for assuming this, but it actually turns out that food was scarce enough in human history that humans never actually evolved a limit on how much fat we will store. If we keep consuming a caloric surplus the body will keep creating fat to store it. This is the body working as intended. Things would be different if humans had a more reasonable max body fat percentage.

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