Redefining Obesity: New Criteria and Implications

A recent study introduces a revised understanding of obesity, highlighting potential underestimations of its prevalence. The traditional reliance on body mass index (BMI) as a marker may not suffice in identifying all individuals with the condition.

Currently, it’s estimated that 40% of adults in the United States are affected by obesity. These figures predominantly stem from assessments involving BMI, which calculates weight in relation to height. However, BMI fails to differentiate between body fat and lean mass, like muscle and bone. This limitation has spurred a re-evaluation of obesity definitions.

Last year, an international commission described “clinical obesity” as a chronic illness marked by systemic and tissue dysfunction due to excess body fat. Dr. Brian P. Lee from Keck Medicine at the University of Southern California aimed to gauge how many individuals might fall under this updated definition.

Dr. Lee and his team analyzed data from a representative sample of 5,600 adults. They calculated excess body fat prevalence using waist and other body measurements alongside BMI, as advised by the commission. They also examined organ dysfunction and limitations in daily activities. Preliminary results indicate that half of the adults categorized as overweight by BMI could be classified as having clinical obesity under the new criteria. Even individuals with a normal BMI might qualify as having obesity.

Dr. Francesco Rubino, chair of the Lancet Diabetes & Endocrinology Commission on Obesity, praised the initiative to recalibrate obesity prevalence calculations. Yet, he expressed concern that the study might have overestimated numbers due to its criteria. The study classified those with excess body fat and clinical complications like liver fibrosis or walking difficulties as having obesity.