Wanda Hoffman was a 24-year-old white woman who presented with a chief complaint: "I have problems throwing up." These problems began in early adolescence, when she began dieting despite a normal BMI. At age 18, she went away to college and began to overeat in the context of new academic and social demands. A 10-pound weight gain led her to routinely skip breakfast. She often skipped lunch as well, but then famished, would overeat in the late afternoon and evening. She felt out of control. Worried her habits would lead to weight gain; she saw self-induced vomiting as a way of controlling her fears. She appeared well nourished. Her BMI was normal at 23. Based on these symptoms, the best diagnosis for Wanda is:________