My brother's girlfriend is a trainer and just graduated with a degree in nutrition. She constantly guides my family through what is healthy and necessary and what is not. Honestly, what I personally see (from experience) eating disorders to be is ignorance paired with insecurity. A lot of people simply do not have the correct information readily available as to how to 'diet' and do it properly. There is one diet I find particularly interesting because it is the diet of some of the most beautiful women of the world, or at least what beauty is considered to be now a days. It is the diet that Supermodel and Victoria's Secret Angel, Adrianna Lima, uses before runway show day. It seems ridiculous, paired with their strenuous workouts, but it is what gives them the final touches to their insane bodies before runway day and makes a lot of young women feel awful about themselves come time for the big day.
It all comes down to what is healthy versus what is sightly. What is in versus what is out. In the long run though, the only thing that should matter is the prize of health and vigor of body paired with self-esteem to match regardless of a man or woman's shape.
http://www.eonline.com/news/hwood_party_girl/adriana_lima_defends_liquid_diet_double/274140 (Here is the article!)