This video segment, adapted from NOVA, documents a ballerina's experience with a potentially deadly eating disorder: anorexia nervosa. Research suggests that a brain chemical called serotonin plays a prominent role in regulating appetite—a key factor in eating disorders. The disruption of serotonin levels by dietary changes can lead to a vicious cycle that prolongs the disorder. By restoring nutrition to her diet, however, the dancer in the video is tackling her eating disorder and resuming her career.This video is available in both English and Spanish audio, along with corresponding closed captions.