The reason why I mosly I play Elves and Tieflings in D&D is so I can be hot, handsome, fit and at least be popular with the opposite sex for once.
And thats a totally valid reason, no less than others. I am not fat IRL and I'll gladly play as a fat merchant or nobleman, because I think it adds the extra flavor and conveys the looks of someone who can afford some meats and jellies more often.
Edit: but I have to admit that I'd been fat before I served in the army and I know how it feels when compared to being lean.
