A 17 year old female is brought in by her parents. She states that “my parents think I’m too thin, but I just want to be healthy.” Her parents are concerned over her significant weight loss over the past 6 months. She was previously an active, high-achieving student and cross-country runner. Recently, she has become preoccupied with food, calories and exercise. She follows a strict diet of under 800 calories per day and exercises excessively, sometimes running twice daily. She denies feeling underweight and insists she still has “fat to lose”. She has not had a period for 5 months. She avoids meals with her family and cuts food into tiny pieces. She becomes irritable when her eating is questioned and has withdrawn socially. She denies any history of purging, binge eating or substance use. Her family say she has always been a perfectionist, whether it was to do with work or her sports, but are concerned she is “taking it too far.”