Obesity Trends May Be Going in the Right Direction for the First Time in a Decade

For the first time in more than a decade, the prevalence of obesity among adults in the United States appears to be on the decline, according to an analysis of nationwide trends in body mass index (BMI) and obesity.

In the cross-sectional study, the mean population BMI increased annually between 2013 and 2021 before plateauing in 2022 and decreasingly slightly in 2023.

“While obesity remains a considerable public health concern, the observed reductions in obesity prevalence suggest an encouraging reversal from long-standing prior increases,” write investigators led by Benjamin Rader, PhD, MPH (Boston Children’s Hospital, MA), in a research letter published December 13, 2024, in JAMA Health Forum.

Rader and colleagues say the rising popularity of glucagon-like peptide 1 receptor agonists (GLP-1RAs) for weight loss may be behind the shifts in BMI, although they don’t rule out other explanations like demographic and behavioral changes that may have occurred as a result of the COVID-19 pandemic.

For the study, the researchers examined linked medical and insurance claims to electronic health records from the Optum deidentified Market Clarity Data on 16,743,822 US adults, the majority of whom were between the ages of 26 and 75.

The most notable decrease in BMI occurred in the South, where a sensitivity analysis found that the proportion of adults with obesity was 46.2% in 2021, 46.0% in 2022, and 45.6% in 2023. The South also had the highest rate per capita of GLP-1RA dispensing at 6% compared with 5.1% for those living in the Midwest, 4.4% for those in the Northeast and 3.4% for those in western states.

However, “dispensing does not necessarily mean uptake, and the South also experienced disproportionately high COVID-19 mortality among individuals with obesity,” Rader and colleagues note.

Obesity and BMI are also imperfect proxies for adiposity, so “future studies should investigate alternative body composition measures and potential causes for the observed shifts,.” they add.

Commenting on the study for TCTMD, Sean Heffron, MD (NYU Langone Health, New York, NY), said the analysis has limited statistical power in comparison with those done using data from other sources like the National Health and Nutrition Examination Survey (NHANES), which as of September 2024 indicated only a nonsignificant downtick in obesity prevalence in the US between 2021 to 2023.

While there is reason to be hopeful that the prevalence of obesity may be trending downward and continues to do so, Heffron said, the NHANES data suggest a troubling increase in the percentage of the population with severe obesity (BMI > 40) over the past 10 years.

Last month, the Global Burden of Disease (GBD) study showed that more than 170 million US adults 25 years and older are living with overweight or obesity, with the prevalence in both sexes exceeding 40% in all 50 states and Washington, DC.

Heffron said it’s unclear how long it may be before substantial shifts are seen in obesity trends in the US as a result of efforts to get eligible patients onto GLP-1RAs or what proportion of patients with obesity would need to use them to see an epidemiological impact.

“These are very important medications that not only help patients achieve weight loss, but they improve cardiovascular outcomes,” he added. “I think they will eventually have a huge role in decreasing the obesity epidemic . . . but we have a long way to go. These medicines aren't going to fix institutional and environmental and societal problems that contribute to obesity.”