Health Moves

…helping you toward your goal of optimal health for your mind, body, and relationships

Q: I have a friend who is 5 feet 4 inches tall, weighs 100 pounds, and looks thin. She is 15 years old. According to the Body Mass Index chart, her BMI is 17.2. A number under 18.5 means the person is underweight. I’m afraid she may have an eating disorder. What should I do?
A: The answer to your question has two parts. The first part addresses how you are interpreting the BMI value. For an adult, a BMI under 18.5 can indicate underweight. However, there are special charts for interpreting the BMI of boys and of girls ages 2 to 20 years (Body Mass Index-for-Age). According to this chart, your friend’s BMI is not a cause for concern. The BMIs of children and teens are interpreted differently because their bodies are still growing. It’s normal to grow at different rates and in different ways. In addition, some people are naturally slim; they come from slim families. The second part of the answer to your question addresses your concern about a possible eating disorder. If you are basing your suspicion on the BMI alone and your friend has no signs of an eating disorder, you probably have nothing to worry about. If you are noticing certain behaviors (regardless that her BMI is in the "normal" range), you are right to be concerned. Has she been losing weight? Does she: Complain about how her body looks? Think she is too fat? Talk a lot about dieting? Throw away her food without eating it or eat extremely small amounts? Go to the bathroom a lot, perhaps to make herself vomit or because she is using laxatives? If you suspect your friend needs help, you can try talking to her. You also should tell your concerns to an adult you trust, such as a parent, the school nurse, or a favorite teacher. They may talk with your friend or her parents. It may turn out to be a false alarm, but it’s better to be safe than sorry.

Q: Sometimes I get tiny, white sores on the inside of my cheek. Does this mean I have herpes?
A: What you describe sounds like a canker sore. These painful ulcers appear inside your mouth—on your tongue, your soft palate, and inside your cheeks—not on your lips. Doctors don’t really know what causes them. Stress, eating certain foods, or biting the inside of your mouth may bring them on. They are not contagious. The herpes type I (and sometimes type II) virus causes cold sores (or fever blisters) that almost always appear on the lips, rarely inside the mouth. They are contagious. A doctor can tell you for sure if what you have is canker sores. You should see a doctor if the sores spread, last more than three weeks, are extremely painful, or if you get a high fever when they appear.