Q: My 15-year-old daughter seems to be run down all the time. She lives on candy and sweets. I wonder if she could have sugar intoxication.

A: We're not sure what you mean by sugar intoxication. Ingestion of large amounts of refined sugars (found in candies and other manufactured sweets but not in fresh fruits) may be bad for your teeth, and they should be consumed sparingly by individuals with diabetes.

But in people without diabetes, eating sweets (even in "large amounts") does not lead to the symptoms you describe. We do believe, however, that consumption of refined sugars should be limited since these products usually contain large amounts of fat (chocolate is an excellent example) but very few essential nutrients.

Many people claim that symptoms such as dizziness, fatigue andlethargy result from low blood sugar. However, a recent study showed that individuals who thought they suffered from this disorder had normal blood sugars at the time they experienced these symptoms.

There are a number of common conditions that could cause your daughter to feel tired all the time. These include anemia, depression, stress and infectious mononucleosis. If your daughter's symptoms have persisted for more than a few weeks, an evaluation for these and other conditions is in order.

Dr. Wilson is director of general pediatrics at the Johns Hopkins Children's Center; Dr. Joffe is director of adolescent medicine.