A 17-year-old female patient presents for a routine health visit. She has lost 15% of her body weight since her last visit 6 months ago, despite a reported increase in food intake. Her mother expresses concern about her excessive exercise and preoccupation with her body image. During the review of systems, the patient admits to feeling cold all the time, experiencing abdominal pain, and noticing hair thinning. Based on these findings, which of the following conditions should the medical assistant be most concerned about?
Binge eating disorder
Pica
Bulimia nervosa
Anorexia nervosa