Most other weight-reduction programs have a 50 percent success rate. The key, say program organizers, is motivating kids to change their lifestyle. To qualify for the program, children or teens must have a body mass index (BMI) greater than the 95th percentile on the Centers for Disease Control and Prevention's growth chart. A child with a BMI greater than the 85th percentile may also be eligible, if the child's parent is overweight or the child has an obesity-related condition like diabetes or high cholesterol.

"Red light" items include cheeseburgers, chicken nuggets, whole milk and frozen yogurt. Grains, fruits, beans, meat and fish get a "yellow light," signaling they can be eaten frequently, but in moderation. Vegetables and water get the "green light." Pediatrician Thomas Robinson directs the Center for Healthy Weight at the Lucille Packard Children's Hospital. Recently, he moved certain popular foods, such as pizza, from cautious yellow to stoplight red. Stop Before You Eat Pizza With so many high-fat, high calorie foods in so many places — birthday parties, sports events, holiday parties, even Grandma's cookie jar — Zedeck says it's tough for kids to make healthy choices. The program combines an easy-to-understand traffic light system to help kids and their fiber optics understand that there are foods that should be consumed rarely.

At least one legal guardian must agree to attend each weekly, 90-minute learning session with the child. Yet the parent can't make the decision for the child. Both must want to enroll. They literally sign a contract promising to come every week for six months. "[Children have] to explain they want to do this [for] themselves," says Cindy Zedeck, an education specialist in charge of the program. "It can't be the result of pressure from the parent, because if they feel pressure or aren't clear why they're here, it won't be successful."