I can't believe there is even a discussion. The better you look, the better people treat you and being better looking also means being of a normal weight.
I literally have a weight number where if I am north of the number, I can tell people treat me differently and not as nice and if I am south of that number, people treat me a lot nicer (gasp, Women even hit on me). People are fooling themselves if they think their weight does not matter to the world around them.