Severe Obesity Rates Surge in U.S. and Driven by Rise in BMI

A research letter published in The Lancet Diabetes & Endocrinology reports a sharp increase in extreme forms of obesity in the U.S. Investigators from Pennington Biomedical Research Center found that while the overall prevalence of obesity (body mass index [BMI] ≥30 kg/m²) rose by 29.5% from 2001 to 2023, the prevalence of adults with a BMI greater than or equal to 60 kg/m² increased by 210% over the same period.

The analysis was based on measured height and weight data from non-pregnant U.S. adults aged 18 years and older, using the National Health and Nutrition Examination Survey (NHANES). Data was evaluated in 4-year intervals across 22 years. The study focused specifically on severe obesity, a subgroup often underrepresented in public health reporting, where all BMI greater than or equal to 30 kg/m² categories are typically combined.

“Most attention is focused on the category of general obesity, which starts with a BMI of 30 kilograms per square meter, but there is less attention paid to the prevalence of obesity of 60 BMI or greater,” said Dr. Philip Schauer, director of the Metamor Institute at Pennington Biomedical. This group faces greater clinical burden, impaired mobility, and higher healthcare costs.

The study is among the first to document increases in BMI categories between 50.0–59.9 kg/m² and greater than or equal to 60 kg/m². Individuals in the latter group are more likely to require mobility aids, experience frequent hospitalizations, and encounter employment limitations due to disability.

Despite the growing use of GLP-1–based medications for weight management, the researchers emphasized that the efficacy of these treatments in this population remains unclear, as most clinical trials enroll participants with average BMIs of 37–38 kg/m².

With more than 850,000 U.S. adults now estimated to have a BMI greater than or equal to 60 kg/m², the findings highlight urgent healthcare system challenges—including patients exceeding the weight limits of imaging equipment. The authors call for refined data segmentation and tailored clinical strategies to better support this high-risk population.

Reference:

Kachmar M, et al. Lancet Diabetes Endocrinol. 2025 Apr 24:S2213-8587(25)00069-5. doi:10.1016/S2213-8587(25)00069-5