Bodies essentially needing to act as life support for a full human or two worth of extra tissue age like shit. On top of that, fat's really just a single symptom of an underlying issue with these people. And that's an inability to say no to immediate gratification in order to prevent something bad in the future. They do it with everything. The person who can't say no to cake also can't stop herself from going out without sunblock. Or smoking. Or drinking too much too often. They're usually a big mess of things that have a high chance of causing someone to age poorly. And they're pretty much the norm these days. It's hard not to age well in comparison.