Why do you think that anorexia nervosa is so much more prevalent in the U.S. than in other developed countries?

Why do you think that anorexia nervosa is so much more prevalent in the U.S. than in other developed countries?
Why are we seeing a rise in children and adolescents who are diagnosed with anorexia nervosa?
What part does the media (especially social media) play in anorexia nervosa?