Just had dinner with friends. They said a classmate just got diagnosed with eating disorders. I didn't know what to say. Why would someone get that?

Lo self image. Binge eating may relieve anxiety. Purging or restricting are attempts to feel in control when there is self disgust or feeling overwhelmed. Related to obsessive-compulsive disorder, as food becomes an obsession. Biological-esp serotonin-disorder. Meds and behavioral tx help.
Genetics. Play a role in the development of eating disorders as well as other factors. It is not their fault!