I agree with a cultural approach to endemic obesity a lot more, not 100% sold on it because societies like Japan have low obesity rates, despite being alienated as fuck

Well I'd say the fact that there's such a difference between Japan and the US shows that the root is cultural, as otherwise you're left with "Japanese are better at personal responsibility than Americans". It's just that alienation isn't the only important factor. I'd say that having a highly alienated population isn't, on its own, sufficient to cause high obesity rates, but fixing it is necessary to seriously address obesity in the US.