Six states now make schools measure students' heights and weights for so-called body mass index report cards.

Children who are inactive—spending time watching TV or sitting at a computer—are at higher risk for obesity, especially when their diet contains lots of high-calorie foods and beverages.

For overweight children 7 and older, the initial goal is to keep them from gaining more weight. Changes in eating habits and exercise are gradually introduced to trim pounds.

Childhood obesity is more prevalent in the Northeast, followed by the Midwest, South and West. It is also more prevalent in cities than in rural areas.

Ask a parent to name the greatest health threat to children and you'll hear about drinking or drugs. Rarely will anyone cite obesity -- even though it can lead to heart disease, high blood pressure or diabetes.

Most weight problems are caused by too little activity and too much food. Most children who are overweight don’t need to diet.