In my experience, mostly no. But that could have been painted by the fact that I, too, was the fat kid for most of my youth. Despite that, I found that I could sometimes buddy up with a more attractive guy with either a better physique or social skills. I was a loser, but I could do that because I naturally treat everyone the same. Anyway, even attractive young men seem to view themselves as lesser creatures whose esteem would be improved by obtaining an attractive female. True, that often boosts one's esteem, but there's little self-love in that picture. Of course some guys do have a level of independent self esteem, but it is surprising how many attractive men don't think highly of themselves.

As far as stability, I think it has to do a lot with your physical and mental health. I noticed that most of the guys I knew who were out of shape and had basement dweller habits tended to stick with self-hating tendencies. And some people who didn't have key periods in their life, like having a mate or living on their own, have stayed that way after about age 26.