10 years to 14 years

Focus on: Healthy weight
Obesity is a problem that affects more than 15 percent of all children between ages 6 and 19 living in the United States, according to the American Obesity Association. Those children are at increased risk for type 2 diabetes, heart disease, asthma, high blood pressure, sleep apnea, and other serious health problems. Being overweight can also trigger depression and other mental health issues. Fortunately, weight problems in children can be prevented and reversed.

Let your child shop. Reinforce healthy food habits by getting your children involved in grocery shopping and meal preparation. "Let them pick out food you can both feel good about, or put them in charge of making dinner once a week," Marshall says. "This will provide them with the control they want and need."

Exercise regularly. Get your child outside more, or dancing to music inside, even if she isn't involved in soccer or other organized sports. "Exercise has many different forms," Tanner says. "Find activities your child enjoys and do them as a family."

Turn off the TV. U.S. children between ages 8 and 18 spend an average of 44.5 hours per week in front of a TV, video game, or computer, according to the Kaiser Family Foundation. The National Institute on Media and the Family reports that kids who watch more than three hours of television a day are 50 percent more likely to be obese than kids who watch fewer than two hours.

Monitor school lunches. Your child may be eating healthy at home but getting fat at school. That's because many school cafeterias and vending machines offer soda, hot dogs, pizza, candy bars, and more. The U.S. government has mandated through the Federal School Wellness Policy that schools begin to provide better nutritional education, physical activities, and healthier food. As part of this effort, help decide what food is sold at your child's school, says Marshall, who is involved in designing the healthy lunch program for her children's school in Madbury, New Hampshire. To learn more, talk to your school's principal or go to www.fns.usda.gov/tn/healthy/wellnesspolicy.html.

Be a Role Model. Your kids mimic you. "You cannot sit on the couch munching chips and cookies and expect your child to eat her fruits and vegetables," Tanner says. Besides, numerous studies have shown that a child is at greater risk of becoming obese if one or both of her parents are obese, Baral says.

Encourage balance. Swim practice. Music lessons. Study groups. Debate club. The number of extracurricular activities piled on a child's plate these days is growing. Many kids enjoy and thrive on these activities. But according to a 2007 study published in Pediatrics by the American Academy of Pediatrics, they also need time to do what kids do best: play. The study found that unstructured, exploratory play—which contributes to the "cognitive, physical, social, and emotional well-being of children and youth"—is being edged out for many kids by increased attention to academics and enrichment activities. The result? A growing number of kids are experiencing anxiety and stress, which can harm them physically and emotionally. The goal is to help your children find balance, says Luanne Southern, MSW, senior director of prevention and children's mental health services at Mental Health America. "Allowing time for play, friends, exercise, and rest is so important."

Build connections to nature. According to Richard Louv, author of Last Child in the Woods (Algonquin, 2005), children are becoming increasingly alienated from nature—in large part because of television time. This disconnect deprives children of an opportunity to enjoy and learn about nature, but it also may harm kids physically. One study suggests that "direct physical contact with nature reduces symptoms of ADHD," Louv notes. "It also may help with depression, obesity, and stress reduction."

Snuff out smoking. Girls 12 to 18 make up the fastest-growing group of smokers in the United States, and every day more than 4,000 kids ages 12 to 17 start smoking. Prevent your child from picking up this dangerous habit—which has been linked to increased risk of heart disease, diabetes, and many types of cancer—by talking to them early about why smoking stinks. Good resources include www.tobaccofreekids.org and www.kidshealth.org (click on "parents' site" and "positive parenting.").

Next page: 14 years to 18 years