I'm American. In my country, people are fat F's. I'm not. I workout and take care of my body. What's bad?

Fat people tend to give me dirty looks when I run the neigborhood. People at the firehouse, when I volunteered, got weirded out when I would not join them for pizza. They got strange when I was doing push-ups when they were wathing Nascar. People in general think it is alien to see people jump rope. all these things in physical activity and taking care of yourself are all rather common. Why do people get all defensive around me? I did nothing wrong other than do what I like to provoke these actions.