In 2001, the U.S. Surgeon General issued the Call to Action to Prevent and Decrease Overweight and Obesity to stimulate the development of specific agendas and actions targeting this public health problem. In 2002, Congress charged the Institute of Medicine (IOM) with developing a prevention-focused action plan to decrease the number of obese children and youth in the United States. The primary emphasis of the charge was to examine the behavioral, social, cultural, and other broad environmental factors involved in childhood obesity and to identify promising approaches for prevention efforts. To address this charge, the IOM appointed a committee of 19 experts in child health, obesity, nutrition, physical activity, and public health. The committee's action plan is described in this report, titled Preventing Childhood Obesity: Health in the Balance.