Americans are facing an epidemic of overweight children. Among children and adolescents, an estimated 16.9 percent are obese, according to the National Health and Nutrition Survey.

Overweight children suffer from being teased and from the resulting poor self-esteem. They may also avoid sports or have trouble succeeding in them.

Being overweight can lead to medical problems in childhood (high blood pressure and cholesterol, sleep apnea and joint problems, among others). It also means that these and other disorders are likelier in adulthood (for example, cancer, diabetes and heart disease). Childhood obesity is a major risk factor for obesity in adulthood.

Genetics plays a role in obesity, so any child with overweight parents may inherit the tendency. In the U.S., children also run a gauntlet of fast foods and processed foods, full of unhealthy fats, sugars and salt in oversized portions, nutritionally “empty” calories that don’t supply a balance of necessary nutrients.

Healthier foods, with more fiber and protein, are not the ones being pushed in TV ads and fast-food joints — and they may be more expensive. Sadly, our country’s poorest children are most at risk.

Added to our unhealthy diet is our couch-potato culture. TV, video games and the Internet take time away from physical activity.

Additional factors affect weight gain. Some children may turn to food for comfort and soothing. Others may never have learned to pay attention to hunger and fullness cues. We’d expect these factors to be more common in children who rarely get the chance to enjoy sitting down for relaxed mealtimes with their families, but instead eat in front of the TV and snack and graze all day.

Children can better manage their appetites when meals occur at regular, predictable times with a beginning, middle and end — such as salad to start, then the main course and finally dessert.

If you are concerned about your child’s weight, let your pediatrician know — early. In any case, your pediatrician should be monitoring your child’s growth (weight and height) at each routine visit. Overweight children under 2 are likely to be obese as older children. Uncommon medical causes of weight gain, including hormone abnormalities, need to be considered. Depression can also lead to excess weight gain.

Many children gain a little weight just before entering puberty. Unless the gain is excessive, it shouldn’t be cause for concern. Children this age are often very sensitive about their appearance, and a parent’s reaction to bodily changes can be very upsetting.

Don’t comment on such a predictable gain. If you’re concerned, discreetly ask for your pediatrician’s advice at your child’s routine visit. If your child is concerned, listen to her and let her know that you understand that the weight gain bothers her — but assure her that this is a normal change and that you’re not worried.

PREVENTING OBESITY

• No grazing: three square meals (and maybe a morning and afternoon snack) — and that’s it.

• No TV at mealtimes, no eating while watching TV and no TV in children’s rooms — ever. The total number of hours per day of TV is a strong predictor for obesity.

• Keep junk foods (high-fat, high-sugar foods like fries, chips, soda, candy, doughnuts and so on) out of your home. Once your child becomes addicted to their intense tastes, healthy foods are likely to lose out. Don’t make an issue of it, though, lest junk food just seem more desirable.

• Your child needs physical activity every day. Walk or bike together instead of driving whenever you can. When you can’t get out of the house, you can put on some music and dance together. Keep exercise fun, low-key and without pressure to perform.

• Make meals a fun, relaxed time for being together as a family.

Questions or comments should be addressed to Dr. T. Berry Brazelton and Dr. Joshua Sparrow, care of The New York Times Syndicate, 620 Eighth Ave., 5th Floor, New York, N.Y. 10018. Questions may also be sent by email to:

nytsyn-families@nytimes.com