High Prevalence of Clinical Obesity Seen Even With Normal BMI

THURSDAY, June 4, 2026 (HealthDay News) — The prevalence of clinical obesity is high among those with normal body mass index (BMI) values, according to a research letter published online June 2 in the Annals of Internal Medicine.

Hirsh Elhence, M.D., from the University of Colorado Anschutz Medical Campus in Aurora, and colleagues quantified the prevalence rates of excess adiposity, preclinical obesity, and clinical obesity by BMI class using anthropometric measures. Each patient was classified by BMI class (underweight, normal, overweight, or class I, II, or III obesity), excess adiposity status, preclinical obesity status, and clinical obesity status.

Data were included for 5,642 nonpregnant U.S. adults. The researchers found that the overall adjusted prevalence of excess adiposity varied by definition from 40.9 to 77.6 percent for abnormal BMI plus one abnormal anthropometric measure versus two to three abnormal anthropometric measures, regardless of BMI. Lower overall adjusted prevalence was seen for preclinical versus clinical obesity (24.2 versus 53.8 percent). There was an increase in adjusted clinical obesity prevalence by BMI class: 26.1, 50.3, and 85.3 percent for those with normal BMI, overweight, and class III obesity, respectively.

“BMI is problematic because it does not specifically measure body fat and instead reflects total body weight, which includes muscle and bone,” principal author Brian P. Lee, M.D., from the University of Southern California in Los Angeles, said in a statement. “So a muscular person can have a very high BMI but not have excess fat, while someone without much muscle can have a normal BMI but have excess fat causing health problems.”

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