New research has found that, for the first time in over 10 years, obesity prevalence in the United States has actually decreased.

However, the slight nudge downward may be due to factors other than improved diet and lifestyle.

Regional and Demographic Variations

The cross-sectional study, published in JAMA Health Forum on Friday, analyzed de-identified insurance data from Market Clarity Data, which includes linked medical and insurance claims and electronic health records from 2013 to 2023.

The researchers found that the average population body mass index (BMI) rose annually from 2013 to 2021, plateaued in 2022, and decreased slightly in 2023.

According to the findings, this decrease in obesity prevalence was particularly noticeable in females, people aged 66 to 75, and those residing in the southern United States.

“The findings suggest that BMI and obesity prevalence in the US decreased in 2023 for the first time in more than a decade,” the study authors wrote.

Important Caveats

Despite these findings, the researchers emphasized important caveats regarding the decrease.

The most significant reduction in obesity rates occurred in the South, which also recorded the highest per capita dispensing rates of glucagon-like peptide-1 receptor agonists (GLP-1RA), which include Ozempic, Mounjaro, and Saxenda, for obesity treatment.

Moreover, the researchers pointed out that the southern United States experienced disproportionately high COVID-19 mortality rates among individuals living with obesity. This factor may have contributed to a reduction in the overall population of people classified as obese in the region.

“Obesity and BMI are imperfect proxies for adiposity; thus, future studies should investigate alternative body composition measures and potential causes for the observed shifts,” the authors wrote.

According to the researchers, the findings are limited by possible selection bias and compositional changes. For instance, BMI recorded during participants’ medical visits may have distorted estimates and made the data suggest a slightly higher obesity prevalence. However, the authors added that early trends still mirrored authoritative data from the World Health Organization.

“While obesity remains a considerable public health concern, the observed reductions in obesity prevalence suggest an encouraging reversal from long-standing prior increases,” the researchers noted.