Eating disorders are emotional disorders, and are not just about eating. People with eating disorders might have depression and/or anxiety as well as other emotional issues. For example, people who have eating disorders often have felt sad, even in childhood. Sometimes these people have felt anxious in general, or have had anxiety in social situations for most of their lives. These are examples of some of the emotional/genetic precursors to eating disorders.
The actual eating disorder behaviors (restricting, purging, excessive exercising, etc.) become the coping mechanism for the anxiety and/or depression. This is why it can be difficult to get over the eating disorder if the primary focus is on eating and regulating behaviors. Eating is the surface issue and the coping mechanism, but NOT the actual root of the problem.
In summation, when thinking about an eating disorder or treatment for the disorder, realize that the behaviors are only on the surface. When in therapy, it is important to make sure that issues of relationships/connecting, self-esteem, body image, anxiety, depression, coping, family issues, and more, are being addressed. Therapy is an exciting process to becoming and discovering a happier and healthier you, while working on experiencing emotions in a balanced and healthy way.