Anorexia and bulimia are very serious problems for young girls that's true. However more and more these days obesity is also becoming a serious problem as well, and it is just as dangerous. It can cause an enormous amount of health and emotional problems just as the other two can.
Teens are under more and more stress these days and for some of them food is becoming their drug of choice. It's easy to get, cheap, and can give a quick "high" or feeling of relief or comfort.
Everyone is talking about the cosmetic appearance of being overweight but for alot of teens it goes deeper than that. Anorexia and bulima are merely symptoms of a much deeper problem. So is obesity.