While eating well is an important part of a healthy lifestyle, some eating disorders in adolescents are being masked by “successful dieting.”

It can be difficult for doctors to draw the line between healthy eating and an eating disorder, especially in the case of “Sophia,” who at 15-years-old was fit but not too thin. But Dr. Sara Buckelew, an associate professor of adolescent and young adult medicine in the Department of Pediatrics, and Daniel Le Grange, the Benioff UCSF professor in children’s health in the Department of Psychiatry and Pediatrics, say that anorexia nervosa is determined by eating patterns, not just weight.

Sophia was an active teen who loved sports. At five foot four and 105 pounds, she wasn’t considered to be dangerously thin. But when Sophia’s pediatrician discovered she weighed 150 pounds at her last annual check-up, she knew something was amiss. The pediatrician’s suspicions of anorexia nervosa were confirmed when she learned Sophia’s diet was restricted to fruit and crackers, and that she performed 200 sit-ups before school every day.

“With the prevalence of childhood obesity, eating disorders can masquerade as ‘successful dieting,’” Buckelew and Le Grange wrote. “But anorexia, a disease of self-starvation, is no longer only seen in people whose weight dips to double digits. Increasingly, we see it in adolescents of normal weight who used to be overweight. Like typical anorexia, their condition can be fatal if healthier eating patterns can’t be re-established.”

Buckelew and Le Grange understand that parents can feel responsible for their children’s eating disorders, but assures them they are not. They suggest that parents talk to a pediatrician or contact an eating disorder facility if they suspect their children are suffering from anorexia nervosa.