The National Health and Nutrition Examination Survey (NHANES) is a survey conducted through the Centers for Disease Control and Prevention and the National Center for Health Statistics that collects data on the prevalences of various diseases. Every two years, a sample of over 5,000 people from 15 different counties are surveyed around the country as a representation of the demographics of the general population. NHANES uses a stratified, multistage sample of non-institutionalized civilian residents and is comprised of an at-home questionnaire and standardized health examination performed by trained individuals (NHANES). The age-adjusted prevalence of obesity in 2013-2014 was 40.4% among women and 35.0% among men. For morbid obesity, the rates were 5.5% and 10% for men and women, respectively (JAMA). The overall obesity prevalence showed that while trends in male obesity have somewhat stabilized since 2005, there is a significant, linearly-increasing trend for women (JAMA).
JAMA. (n.d.). Trends in Obesity Among Adults in the United States, 2005 to 2014. Retrieved June 10, 2016, from http://jama.jamanetwork.com/article.aspx?articleid=2526639
NHANES. (2015). Questionnaires, Datasets, and Related Documentation. Retrieved June 10, 2016, from http://www.cdc.gov/nchs/nhanes/nhanes_questionnaires.htm