Activity anorexia is when someone has limited access to food, say an hour or two once a day, and unlimited access to exercise. The less they eat the more they want to exercise. Inversely, the more they exercise the less they want to eat leading to a nasty cycle of weight loss. This problem is magnified in the world of ballet. Then it is reinforced by people telling these women how beautiful they are and how thin they are while the ballerinas put in hours and hours of work in each day. Nova, a PBS show has an episode “Dying to be Thin” which takes a good look into this world. It is a really good show to see how the individuals handle these situations, what their treatment can look like and how the psychology of treating the disorder works.