OBJECTIVES: To describe the prevalence and secular trends of high weight-for-length among infants (ages, 3-23 months) in the biennial US Department of Agriculture Women, Infants, and Children Program and Participants Characteristic (WIC-PC) Survey from 2000 through 2014 (n = 16 927 120). METHODS: Weight-for-length was considered to be "high" if it was ≥2 SDs above the sex- and age-specific median in the World Health Organization growth standards. Poisson regression was used to calculate adjusted prevalence ratios. RESULTS: The overall prevalence of high weight-for-length increased from 13.4% in 2000 to 14.5% in 2004, remained constant until 2010, and then decreased by >2 percentage points (to 12.3%) through 2014. The prevalence of high weight-for-length was associated with sex (higher among boys), race-ethnicity (highest among American Indians/Alaskan Natives), and with both age (positive) and family income (inverse). The secular trends, however, were fairly similar within categories of these variables. From 2010 to 2014, the prevalence of high weight-for-length decreased in 40 states and 3 (of 5) US territories, with the largest decreases seen in Puerto Rico (-9 percentage points) and Kentucky (-7 percentage points), and the largest increase (+2 percentage points) seen in West Virginia. CONCLUSIONS: Although the current results cannot be considered representative of infants in the populations, the prevalence of a high weight-for-length has decreased among infants in WIC-PC since 2010. These decreases were similar across categories of most characteristics, but there were substantial differences across jurisdictions, possibly reflecting differences in policy and local programs that target maternal and infant health.

Childhood obesity is associated with negative health consequences in childhood that continue into adulthood, putting adults at risk for type 2 diabetes, cardiovascular disease, and certain cancers. Obesity disproportionately affects children from low-income families. Through a collaboration with the United States Department of Agriculture (USDA), CDC has begun to use data from the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) Participants and Program Characteristics (WIC PC) to replace the Pediatric Nutrition Surveillance System (PedNSS) for obesity surveillance among young children from low-income families. CDC examined trends in obesity prevalence during 2000-2014 among WIC participants aged 2-4 years using WIC PC data. Overall obesity prevalence increased from 14.0% in 2000 to 15.5% in 2004 and 15.9% in 2010, and then decreased to 14.5% in 2014. During 2010-2014, the prevalence of obesity decreased significantly overall, among non-Hispanic whites, non-Hispanic blacks, Hispanics, American Indian/Alaska Natives and Asians/Pacific Islanders, and among 34 (61%) of the 56 WIC state agencies in states, the District of Columbia, and U.S. territories. Despite these declines, the obesity prevalence among children aged 2-4 years in WIC remains high compared with the national prevalence of 8.9% among children aged 2-5 years in 2011-2014. Continued initiatives to work with parents and other stakeholders to promote healthy pregnancies, breastfeeding, quality nutrition, and physical activity for young children in multiple settings are needed to ensure healthy child development.