There's a positive feedback loop involved as well. Beautiful people are more likely to have others want to befriend them. This social practice makes them more sociable. Which makes more people want to befriend them.

I don't know if anyone here has lost a significant amount of weight (50+ pounds) while they were still young, but they will confirm this effect. In fact, this effect is often so strong, that people who have lost weight often become very skeptical of people's motivations. People who had never noticed them are now suddenly nice and friendly. This starts to make you wonder if the interest of other people in you, is purely based on your looks or who you really are.