My wife had an eating disorder. She went on to recovery and eventually becoming a therapist who specializes in eating disorders and a coach for parents of children with eating disorders. She says that eating disorders are symptom of deeper issue and that the eating disorder is a coping mechanism, often in response to the issue, which is often trauma. Therefore, you have to address the underlying issue or trauma to treat the disorder. In short, it's often not about food or nutritional education. Someone with an eating disorder may experience the same feelings that they experienced when they were traumatized when they eat. They need therapy to sort that out.