> Fatness is used as a signal of evil, dissolution, and/or moral decay, usually with the unspoken assumption that it's completely obvious that fat people are immoral and disgusting. My favorite novel that uses this trope has to be A Confederacy of Dunces.
I don't remember "fatness" being a signal of evil, and I don't remember any of the non-fat people being any better than the fat ones.
However, it has been quite a while since I read the novel, and I really didn't like it very much. So, my memory may be faulty, and your mileage may vary.