The bad news: In the U.S., approximately 17% (or 12.5 million) of children and adolescents ages 2 to 19 are obese. Since 1980, obesity among children and adolescents has almost tripled.

The good news: This increase may be leveling off, at least in the U.S. Child and nutrition experts have determined that the best strategy is “prevention,” rather than the very unsuccessful strategy of “cure,” which has been used to fight adult obesity. Implementing strategies that focus on health and wellness and not weight seem to work best.

In 2007, an expert committee from 15 associations concerned with childhood obesity wrote a report outlining causes. Both genes and the environment can contribute to the risk of obesity. Twin studies have clearly demonstrated a genetic risk, and the discovery of leptin, ghrelin, adiponectin and other hormones that influence appetite, satiety and fat distribution provide insight into metabolic mechanisms for physiologic risk. Genes, however, are not destiny. Just as behavior and environment strongly influence a person’s risk of developing skin cancer, behavior and environment can influence the development of obesity in genetically at-risk people.

In addition to genetics and environment, recently developed theories point to gut microbiomes as a possible contributor to obesity. Several microbes are linked to obesity in animals and humans, but conclusive evidence for a causative role of microbes in human obesity is lacking. There are numerous concurrent studies from around the world on this topic, including a $30.8-million grant to University of Gottenberg in Sweden last fall to investigate the role of intestinal microbes in childhood obesity. Stay tuned.

In the meantime, we need to implement strategies known to be successful in preventing childhood obesity. The Academy for Eating Disorders Guidelines for Childhood Obesity Prevention Programs states that it’s unrealistic to expect all children to fit into the “normal weight” category. Thus, interventions should be “health promotion,” as the ultimate goal is the health and well-being of all children and health encompasses many factors besides weight.

When programs are based on weight, they often cause untended consequences as demonstrated in an overweight prevention pilot study in Cambridge, Mass., of 8,203 girls and 6,769 boys. When parents were told by schools that their children were overweight or at risk for overweight, they most commonly reacted by starting their children on a diet, making them skip meals or giving them diet pills or herbal supplements. The resulting data suggest that for many adolescents, dieting to control weight is not only ineffective, it may actually promote weight gain.

The Centers for Disease Control and Prevention’s Youth Risk Behavior Surveillance System (2009) recommended limiting “screen time” to no more than two hours a day, while the 2007 National Survey of Children’s Health stated that keeping televisions out of children’s bedrooms and participating in family meals were successful strategies in helping to prevent obesity.

It’s important, too, that parents and teachers control bullying of overweight children and be good role models for healthful eating and regular exercise. Making fruits, vegetables, whole grains, low-fat dairy and lean meat easily accessible for snacking and part of every meal is important. Engaging in walking, hiking or biking with children increases their exercise and their safety.

If shaming overweight adults and children about their weight worked, obesity wouldn’t be an issue. A person’s worth is not based on a number on a scale, but on the individual’s contribution to his or her family, community and world. It is time we all worked together to stop the increase in childhood obesity.

My thanks to Joanna Ikeda, MA, RD, nutritionist emeritus at the University of California in Berkeley, for her assistance with this article.