Key takeaways:
- Using NHANES data from 2017 to 2023, obesity prevalence in the U.S. is 75.2% when excess adiposity cutoffs are used.
- Among adults with a BMI of less than 25 kg/m2, 38.5% had obesity under new Lancet criteria.
The prevalence of obesity was 75.2% among adults in the U.S. when new criteria proposed by The Lancet Diabetes & Endocrinology Commission was used to diagnose the disease, researchers reported in a JAMA Network Open research letter.
As Healio previously reported, a paper published by The Lancet Diabetes & Endocrinology Commission in January 2025 stated adults could be diagnosed with obesity if they had one measure of excess body fat plus a BMI that indicated obesity, two measures of excess body fat without using BMI, or by measuring body fat directly in a DXA scan. Using BMI, waist circumference, waist-to-hip ratio and waist-to-height ratio cutoffs detailed in the commission’s paper, researchers assessed the prevalence of obesity using National Health and Nutrition Examination Survey data from 2017 to 2023.
“Using nationally representative data, we found that three in four U.S. adults were estimated to have obesity,” Kamil Faridi, MD, MSc, assistant professor in medicine in the section of cardiovascular medicine, department of internal medicine at Yale School of Medicine, told Healio. “Importantly, we found that practically all adults with BMI of 30 kg/m2 or higher have obesity, as do 80% of adults in the overweight BMI category of 25 kg/m2 to 30 kg/m2, and nearly 40% of adults in the normal BMI category of less than 25 kg/m2. These findings demonstrate that a large majority of the U.S. population are at risk for or already have adverse health consequences related to excess adiposity and highlight the significant limitations of using BMI alone to define obesity.”
The study group included 14,414 adults, of whom 39.9% had obesity as measured through BMI alone.
Excess adiposity common
When an obesity cutoff of a waist-to-height ratio of more than 0.5 was used, 75.2% of adults had obesity using The Lancet Diabetes & Endocrinology Commission’s criteria. The prevalence of obesity was 100% for adults with a BMI of 30 kg/m2 or higher, 80.4% among those with a BMI of 25 kg/m2 to 29.9 kg/m2, and 38.5% for adults with a BMI of less than 25 kg/m2.
Faridi described the high prevalence of obesity among the study participants as “very concerning.”
Kamil Faridi
“It demonstrates most Americans are at risk of poor health related to obesity-related conditions such as cardiovascular-kidney-metabolic syndrome, including diabetes, heart attack, stroke, heart failure and many other diseases including cancer and infection,” Faridi said.
Of the study group, 80% had an elevated waist-to-height ratio that indicated obesity according to the commission’s criteria, 73.1% had an elevated waist-to-hip ratio and 58.3% had a waist circumference indicating obesity.
Faridi said one of the key takeaways of the study is that health care professionals should not rely solely on BMI to diagnose obesity.
“Waist circumference more appropriately identifies excess adiposity, particularly the metabolically harmful visceral adiposity, but unfortunately waist circumference is rarely measured or used in clinical practice,” Faridi said. “In light of the Lancet Commission’s new obesity definition and recommendations, millions of adults are therefore not appropriately screened, identified or managed for health risks directly related to excess adiposity. Waist circumference measurements should be standardized and included as part of routine health visits and should be documented in the electronic health record.”
More research needed
When researchers used a higher waist-to-height ratio of 0.6, obesity prevalence dropped to 58.4% of the study group. Faridi said using a waist-to-height ratio cutoff of 0.5 may potentially overestimate excess adiposity and some studies use higher cutoffs, which is why researchers also analyzed an alternative cutoff of 0.6.
“Our study was not designed to determine the optimal cutoff values of anthropometric criteria for either obesity prevalence estimates or individual clinical care,” Faridi said. “Even so, our findings indicate that further research is needed to determine the optimal criteria cutoffs under the Lancet Commission definition. In particular, further research on cutoffs is needed based on age, sex and race and ethnicity, and future studies should explore the potential implications of these criteria for screening and management.”
Faridi said the study combined the commission’s definition of preclinical and clinical obesity, and more research is needed to assess the prevalence of each of those conditions separately.
For more information:
Kamil Faridi, MD, MSc, can be reached at kamil.faridi@yale.edu.
