There are two to three times as many obese children in the United States today as there were 20 years ago (Ogden et al. 2002). Data from the National Health and Nutrition Examination Survey (NHANES) indicate that more than one in four preschoolers in the United States were overweight or obese in 2003–2004 (Ogden et al. 2006). Obesity poses serious problems for children’s health and emotional well-being (Institute of Medicine 2005). Many obese children will become obese adults and will experience health problems associated with obesity, such as type 2 diabetes and coronary heart disease, earlier than the current generation of adults (Olshansky et al. 2005). Even more alarming, escalating rates of childhood obesity may lead to a reduction in life expectancy (Fontaine et al. 2003). To arrest this trend, both the Surgeon General (U.S. Department of Health and Human Services 2001) and the Institute of Medicine (2005) have suggested that efforts to prevent obesity should begin early in life.