The difference is that fat people know they're fat and only a tiny minority of people try to justify it or say that it's an optimum state to be in. They might accept it but they don't extol it.
Hold my beer... you haven't met fat people in my family. I mean, my extended family. (pun intended)
There's this idea in (East) Indian and African cultures that being fat = healthy. Being slim is associated with poverty.
Every time I go back to East Africa, my relatives assume things are bad for my wife and me. I have to explain to them that being poor in America means you can't afford a lot of veggies and whole grain foods in the supermarket, that food deserts exist, and we don't live in one.
White bread syndrome:
America - cheapest you can find, bad for you.
East Africa - associated with wealth, because brown bread is more common and cheaper. Also, "White is Right"