@dardardit,
I like some people who are fat and I dislike some people who are thin, but I do have a visceral aversion to the obese.
It may be, as High Sea suggests, genetic programming, but this would belie the fact that in a number of cultures obesity signifies prosperity and is something for which to strive.
For me, it is the vice of gluttony that repels.
Of course, excessive consumption is not limited to food, and so I feel an aversion towards anyone who insists on having, consuming, possessing or experiencing in the excess.
Interestingly enough, some people who share this attitude have been able to modify it based on their ideology: People who live excessive life styles, in terms of what great quantities of wealth can provide are despicable, while people whose eating habits are pathologically excessive to the point of suicide are to be pitied or at least tolerated. People whose sexual appetites are excessive can be understood if they hunger for same gender sex, but less so if they are heterosexual hounds, pigs, players etc. The power mad are OK when they promise to wield their power in ways that compliment personal sensitivities: Thus Obama, Reid and Pelosi can be agents of Good while Bush, DeLay and Gingrich are foul beyond reckoning.
There is room, in a healthy life-style, for some indulgence. Chocolate provides no nutrition, but can be enjoyed with grace, and oral sex is incapable of perpetuating the species but is to be properly appreciated for the pleasure it provides.
One need not be a hardcore Puritan to recoil from behavior so excessive that it jeopardizes physical and mental health.