I think when people have more of their needs fulfilled, it becomes more rational to tackle the final bits. When you're poor, you care about food and having somewhere to live, then at an intermediate level it's about paying the bills and not falling down into the poverty hole, then at a higher level it's succeeding at university, doing good research, making a successful company, but when you have all that, and you can't lose any of these things, then you start also wanting other things, and then playing sports reasonably often becomes extremely natural.
If someone is getting fat, or eating to excess, there has to be something wrong. Something stressing them, something they want to turn away from, to distract themselves. Happy people don't have such needs.
My point is that suggesting that people who eat and gain weight must be unhappy and coping, because happy rich people play sports, is a culturally based assumption. American WASPs and Northern Europeans absolutely stand out in that respect. Even in East Asian cultures with strong social pressure to not gain weight, adults playing sports isn’t common.