> I don’t think it’s unexplained at all. People just don’t like the explanation. People simply eat too much and don’t move enough. It wasn't sourced, but if t

> I don’t think it’s unexplained at all. People just don’t like the explanation. People simply eat too much and don’t move enough. It wasn't sourced, but if the claim that animals on controlled diets have also gotten fatter over recent decades it would mean that there is something more going on here. While weight gain is nearly always an issue of excess calories that doesn't explain why it's suddenly a huge and worsening problem seen all over the planet. An explanation for that is certain to be far more nuanced and will likely involve a large host of factors (your "secondary reasons" for example). At the scale and timeline we're talking about here "People simply eat too much and don’t move enough." is about as useless an explanation as saying "Don't eat so much fatty!" is a solution.