Only way to find out would be to ask her! If she doesn't know a lot about disordered eating, ask her if she can refer you to someone that does. You don't have to stop working with your current therapist, but could add in a new one if needed, just for this one issue.

You can also go here and search by state for therapists that specialize in eating disorders. Treatment facilities are listed first - scroll down past that to the health care professionals section. Treatment - The Elisa Project - Overcoming eating disorders through knowledge.