I blame the culture. Fat shaming is wrong, but the culture has turned that around and made healthy living almost a de-facto "fat shaming by proxy" type weird thing. Anyone who does not agree that a fat person is healthy (but they call it "beauty"), is deemed to be automatically insulting that person.

And, corporates are happy to push around "any body is beautiful" because it rakes in the money.

Edit : The other side of the problem is eating processed and ultra-processed food. Its basically cans and pouches of chemical compounds that overwhelms the body.