Some families go too far by turning healthful eating into a new religion. "Anorexia often starts with healthy eating behaviors, like cutting down on bread and other starches, that evolve to become too restrictive," says pediatrician Tania Heller, director of the Washington Center for Eating Disorders and Adolescent Obesity in Bethesda, Md. "My mom was always into organic food, so she didn't notice when I got on a health kick, running more miles and avoiding all fat in my diet," says Marina Leith, 17, who was treated by Heller for anorexia after dropping 30 pounds in less than two months four years ago. She's now a high school senior, back to a normal weight.
Think positive. How to get a child to a healthy weight in the healthiest possible way? Most experts now favor a positive approach—showing, for example, ways that exercise strengthens the body and refreshes the mind and how certain nutrients in foods help cells, organs, and bones grow properly. Hundreds of schools are now trying out Planet Health, a curriculum developed by Harvard University researchers that disguises obesity prevention by integrating healthful messages about the power of food and exercise into various subjects. Students in math class, for example, come to appreciate the importance of reducing TV viewing by calculating the hours they've spent over their lifetime in front of the set. A 2005 study published in the Archives of Pediatrics & Adolescent Medicine found that middle school girls who had Planet Health in their schools were half as likely to purge or use diet pills as those in schools without it.
A second program adopted by 7,000 elementary schools nationwide, the Coordinated Approach to Child Health, similarly puts the focus on good health habits instead of weight. In class, students use a traffic-light system to identify "go," "slow," and "whoa" foods and take breaks to do jumping jacks. In the cafeteria, fruits, vegetables, low-fat milk, and whole-grain starches are labeled with green-light tags, and pizza gets a yellow light. Gym activities are designed to keep students constantly moving. "Every kid gets a ball to dribble or a hula hoop; there's no lining up and waiting to take a turn," says Philip Nader, professor of pediatrics emeritus at the University of California-San Diego, who helped develop catch. One study found that the program succeeded at preventing the growth in number of overweight students that normally occurs from grade 3 to grade 5. catch schools in El Paso, Texas (with one of the highest obesity rates in the nation), held the line between those grades; elsewhere in the city, the share of overweight girls increased from 26 percent to 40 percent and of overweight boys from 39 percent to 49 percent.
Grass-roots efforts can make a difference, too. Hillcrest Elementary School nurse Kim Glielmi implemented a voluntary walking program last year in which 200 students, parents, and teachers put in 1 mile a day around the neighborhood to reach a grand total for the group. "Our goal had been to walk enough miles to get to California by the end of the year," she says, "but we actually got as far as Hawaii." A community garden project in New York City's Harlem section has increased inner-city kids' appreciation of fresh fruits and vegetables. A program to build bike paths and sidewalks in Marin County, Calif., is prompting more kids to transport themselves to school.
At home. Parents, of course, will have the biggest impact. In her book "I'm, Like, So Fat!" Neumark-Sztainer says the most important thing parents can do is to model healthful behaviors—not preach them—by avoiding fad diets, skipped meals, and too much junk food and by hitting the gym and planning active family outings on a regular basis. A slew of studies have shown that teens who regularly eat home-cooked family dinners enjoy healthier weights, higher grades, lower rates of smoking, less depression, and a lower risk of developing an eating disorder.
Clarified on 9/19/07: This story states that 17 percent of kids are now obese, which means they're at or above the 95th percentile for weight in relation to height. The reason that a greater percentage of kids now fall into the "top 5 percent" category is that the standard measurement charts that define obesity were created using data from the 1960s and '70s when kids weighed less than they do now.