The obese body image reflects the growing obesity of modern western culture. Too much food oil in contemporary art and not enough oil paintings.
We are what we look at. Because genetics rule over visual arts, at least in a (medical) scientific context.
Why do paintings like fat women? Art is futile, chicken are fatty.
Why do i like boobs? Paintings are oily.
Fernando Botero : Fat chicken don't know why boys like breasts.
Do we need pictures of ugly or fat people to fit contemporary realism ? Oil painting that fit fat people, and vice versa.
Most realistic paintings these days can handle the 'full fat' web.