Updated prevalence estimates of obesity among adults in the United States, 2005-2018

Body mass index is an imperfect measure of excess adiposity but is ingrained in both research and clinical practice to define and diagnose adult obesity. The addition of waist circumference measure is recommended to fully capture obesity-related health risks at a population level. The latest reframing of obesity by the Lancet Commission relies on body mass index and waist circumference, as well as organ dysfunction and functional limitations, to differentiate between preclinical and clinical obesity.

Using data from the National Health and Nutrition Examination Survey (2005-2018), we adhere to the proposed redefinition to examine obesity trends in the adult U.S.

In line with previously published estimates of obesity defined solely by body mass index, we show that the prevalence of both preclinical and clinical obesity increased between 2005 and 2018. However, the prevalence of preclinical obesity calculated by BMI plus WC is lower than the estimates derived from using BMI or WC as the sole metrics.

Using the Commission's added measures yields refined population estimates for two categories-preclinical and clinical obesity. These updated estimates separate preclinical cases-at elevated risk and eligible for prevention-from those meeting clinical-obesity criteria, who require intervention.