Obesity and Severe Obesity Prevalence in Adults: United States, August 2021-August 2023.

Introduction: This report provides prevalence estimates of adult obesity and severe obesity during August 2021-August 2023 by age and sex, as well as obesity prevalence by education level. Trends in the prevalence of adult obesity and severe obesity over the previous 10 years are also shown.

Methods: Data from the August 2021-August 2023 National Health and Nutrition Examination Survey (NHANES) were used for prevalence estimates, incorporating examination survey sample weights into the analysis and accounting for the survey's complex, multistage probability design. Measured height and weight were used to calculate body mass index (BMI) to define obesity (BMI at or above 30) and severe obesity (BMI at or above 40). Differences between estimates overall, among subgroups, and compared with 2017-March 2020 were evaluated using tests at the 0.05 level. Data from four NHANES cycles (2013-2014, 2015-2016, 2017-March 2020, and August 2021-August 2023) were used to assess 10-year trends. Polynomial regression was used to test the significance of linear and nonlinear 10-year trends, accounting for the unequal spacing and lengths of survey cycles.

Key Findings: During August 2021-August 2023, the prevalence of obesity in adults was 40.3%, with no significant differences between men and women. Obesity prevalence was higher in adults ages 40-59 than in ages 20-39 and 60 and older. The prevalence of obesity was lower in adults with a bachelor's degree or more than in adults with less education. The prevalence of severe obesity in adults was 9.4% and was higher in women than men for each age group. From 2013-2014 through August 2021-August 2023, the age-adjusted prevalence of obesity did not change significantly, while severe obesity prevalence increased from 7.7% to 9.7%.