• Mayo Clinic Minute: What to do if your teen has an eating disorder

More than half of all American teens will exhibit concerning disordered eating. Dr. Jocelyn Lebow, a Mayo Clinic child psychologist who specializes in treating eating disorders, says parents don't often see the damage even relatively mild eating disorders can cause. Parents usually have no idea what to do when they find out their child has an eating disorder.

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"[Eating disorders] can have long-term effects on your [gastrointestinal] system, on your reproductive system," Dr. Lebow says. "The things that we really worry about [are] obviously there [are] a lot of cardiovascular complications. A lot of kids have arrhythmias or can have heart attacks."

Eating disorders also can affect bone density, which can have long-term health effects.

Dr. Lebow says 1 in 5 teens with severe eating disorders will die – mostly from suicide.

"One of the biggest myths about eating disorders is that they're choices," she says. "Your brain is impacted. When we look at an MRI scan of someone with anorexia, their brain looks different."

Dr. Lebow says that's why it's important for parents to pay attention to their teen's eating habits and get them help right away if they suspect a problem. She says parents should treat an eating disorder as they would any other serious disease such as diabetes or cancer.

"Take your kid to get evaluated," Dr. Lebow says. "Don't hesitate. We know early intervention is key. So overreact. You have my permission."