DEAR DOCTOR K: I'm worried about my 15-year-old daughter. She eats like a bird. She is very thin, but thinks she is fat. I'd like to think this is just a phase some teenagers go through, but could she have anorexia nervosa?
DEAR READER: As with most illnesses, there is not a magic dividing line between having anorexia and not. In fact, there's a big gray zone where people don't meet the criteria for a disease, yet they're not normal, either. An example is "pre-diabetes." Tens of millions of people in the United States have blood sugar levels that are not high enough to be called diabetes, but also aren't normal. It's important to recognize them, because such people have a higher risk for developing diabetes in the future.