I judge heavy people.
That feels very specific, do you have something against heavy people?
No, I think they can be fat and funny.
It's natural to make snap judgments about people based on their appearances, just be willing to see past your initial impressions. People are rarely how they seem at face value, and if you take the time to get to know them then you may be surprised. By judging people too harshly, you deprive yourself of the opportunity to learn their true character.
Nah, I'm going to keep proving them wrong and judge them for being fat.
Judging people by their appearance is a very shallow attitude to do, and you don't want people calling you shallow. If you do not want to change your attitude, then I am afraid that people will see that as a weakness and probably will avoid you for being someone that they cannot have deeper connections with, so I really suggest that you change for the better.