News release

From: American College of Physicians

Many adults with a normal BMI may still have obesity-related health risks

Study highlights the limitations of defining obesity using only BMI

A brief research report estimated how common “clinical obesity” is in the United States using a broader definition that combines body measurements with evidence of obesity related health conditions, rather than defining obesity using body mass index (BMI) alone. The study found that many U.S. adults may meet criteria for clinical obesity even though they would not be classified as obese using BMI-based definitions, highlighting the limits of using BMI as a standalone screening tool. The study is published in Annals of Internal Medicine.

To address the limitations of defining obesity using only BMI, the Lancet Diabetes & Endocrinology Commission introduced “clinical obesity,” a measurement based on expert opinion that considers the presence of both excess adiposity by anthropometric criteria (such as waist circumference) and evidence of subsequent reduced organ or physical functioning. Researchers from the University of Southern California and colleagues analyzed data for 5,642 adults in the 2021–2023 National Health and Nutrition Examination Survey to quantify the prevalence of excess adiposity, preclinical obesity, and clinical obesity using BMI class and anthropometric measures alongside indicators of organ or physical dysfunction. They found that 26% of those with a normal weight BMI and more than 50% of those with an overweight BMI met criteria for clinical obesity. Additionally, the prevalence of excess adiposity was 78% when using two or three abnormal anthropometric measurements compared to 40.9% when using abnormal BMI and at least one abnormal anthropometric measurement. The findings highlight the potential importance of identifying abnormal anthropometric characteristics in clinical settings to better capture individuals at risk for obesity-related health complications.