U.S. is fat and getting fatter

There has not been significant change in the prevalence of obesity in the U.S., with data from 2009-2010 indicating that about one in three adults and one in six children and teens are obese; however, there have been increases in certain demographics, according to two studies being published by JAMA. 

Katherine M. Flegal, Ph.D., Cynthia L. Ogden, Ph.D., M.R.P., and colleagues with the Centers for Disease Control and Prevention, Hyattsville, Md., analyzed data from the 2009-2010 National Health and Nutrition Examination Survey (NHANES) to determine rates of obesity in the U.S. In the analysis for prevalence among adults, rates of obesity (defined as a body mass index [BMI] of 30 or greater) were compared with data from 1999-2008. NHANES includes measured heights and weights for 5,926 adult men and women from a nationally representative sample of the U.S. population in 2009-2010 and for 22,847 men and women in 1999-2008.

In 2009-2010, the age-adjusted average BMI was 28.7 for men and women. The researchers found that overall, the age-adjusted obesity prevalence was 35.7%. Among men, the prevalence was 35.5%, and within race/ethnicity groups, prevalence ranged from 36.2% among non-Hispanic white men to 38.8% among non-Hispanic black men. There were significant increases in obesity for men over the period 1999-2000 through 2009-2010.

For women, the prevalence of obesity was 35.8%, and the range was from 32.2% among non-Hispanic white women to 58.5% among non-Hispanic black women. Over the period from 1999 through 2010, obesity showed no significant increase among women overall, but increases were statistically significant for non-Hispanic black women and Mexican American women. For both men and women, the most recent two years (2009-2010) did not differ significantly from the previous six years (2003-2008).

The age-adjusted prevalence of overweight and obesity combined (BMI 25 or greater) was 68.8% overall, 73.9% among men, and 63.7% among women.

"Obesity prevalence shows little change over the past 12 years, although the data are consistent with the possibility of slight increases," the authors write. "Many efforts both at the national level and at state and local levels focus on reducing childhood obesity. Yet results from NHANES indicate that the prevalence of childhood obesity in the United States remains unchanged at approximately 17 percent; although increases in obesity prevalence may he occurring among males."