A study published in JAMA examines the prevalence of childhood obesity in the United States between 2003 and 2012.
Weight and height were measured in 9,120 participants in the 2011–2012 nationally representative National Health and Nutrition Examination Survey (NHANES). In infants and toddlers from birth to 2 years, high weight for recumbent length was defined as weight for length at or above the 95th percentile of the sex-specific Centers for Disease Control and Prevention (CDC) growth charts. In children and adolescents ages 2–19 years, obesity was defined as a body mass index (BMI) at or above the 95th percentile of the sex-specific CDC BMI-for-age growth charts. In adults, obesity was defined as a BMI greater than or equal to 30. Analyses of trends in high weight for recumbent length or obesity prevalence were conducted overall and separately by age across five periods (2003–2004, 2005–2006, 2007–2008, 2009–2010, and 2011–2012).
The researchers found that in 2011–2012, 8.1% of infants and toddlers had high weight for recumbent length, and 16.9% of those ages 2–19 and 34.9% of adults ages 20+ were obese. Overall, they found no significant change from 2003–2004 through 2011–2012 in high weight for recumbent length among infants and toddlers, obesity in those ages 2–19, or obesity in adults. In addition, the researchers found a significant decrease in obesity among kids ages 2–5 (from 13.9% to 8.4%). On the other side, there was a significant increase in obesity among women ages 60+ (from 31.5% to 38.1%).
The researchers concluded that "overall, there have been no significant changes in obesity prevalence in youth or adults between 2003–2004 and 2011–2012. Obesity prevalence remains high and thus it is important to continue surveillance."