I don't really sympathize with the obese part. That is a health issue that a person does have control over. I am overweight myself and I am trying to do something about it. But the emotional and self esteem issues that go along with being heavy I can empathize with. I certainly wouldn't go and insult a larger sized person, or a thin person. (The bias does go both ways). I also think people don't really understand what a healthy weight is.
I guess what I'm saying is my being overweight is my own fault, maybe that's not the case with everyone. (medical issues and whatnot) I don't want or need sympathy for it. There is a difference between not sympathizing with someone and having outright hostility towards them.
Another poster said people started to treat him better after he lost weight. I don't doubt that, many people are shallow and don't recognize it. But did you act any differently after you lost the weight? Maybe you felt better about yourself and it showed? I know that when I started losing weight I felt a lot better about myself and people seemed nicer. A persons frame of mind tends to influence how they perceive they are being viewed.
I remember reading once this story about a man walking down the road. One traveler asked what the people in the village up ahead were like. He asked, how were the people in the last village. The traveler said they were horrible and dishonest. To that the man said, that is how you will find the people in this village. The next traveler he met asked him the same question, and again he asked them how the people were in the previous village. They said, oh they were wonderful and kind. To that he said, you will find these villagers the same.