More than 26% of people with normal BMI meet proposed clinical obesity criteria based on fat mass and organ dysfunction, US research suggests.

A 2025 Lancet Global Commission defined clinical obesity as excess adiposity, assessed via anthropometric measures rather than BMI alone, that affects everyday activities or contributes to organ dysfunction, such as microalbuminuria with reduced eGFR or steatotic liver disease with hepatic fibrosis.

In an Annal of Internal Medicine research letter this month, US researchers applied these criteria to 5624 non-pregnant adults, aged 20 and older, from the nationally representative National Health and Nutrition Examination Survey in 2021-23.

They found that 53.8% of participants met the definition of clinical obesity, including 26.1% of those with normal BMI and 50% of those deemed overweight by BMI, after adjusting for age, sex and race.