It's funny, I was just thinking last night about which is worse, the fat rich or the thin rich.
The reason for the image change comes out of Veblen I guess. Now that the poor/working class are sedentary, overworked, and overweight, being thin and in good shape is a major signal that you are not working class. A hundred years ago, when the poor were on this side of starvation, it was cool for the rich to be fat. In countries, where most are still nearly starving, it's still cool to be fat.
The other difference between the fat rich and the thin rich is the level of righteousness: the fat rich look like pigs -- so the opprobrium of gluttony/greed is still upon them. But the thin/well-exercised rich look like "beautiful people" who are capable of the "hard work" and "discipline", which, as we all know, will make us all rich.
All in all, being able to nurture contempt for the rich in the masses would be a good thing. Some kind of Monty Python upper-class-twit-of-the-year award, but translated into American terms....
Joanna