Defining obesity or delaying treatment? New paper sparks medical controversy

Elizabeth Cooney is STAT’s cardiovascular disease reporter, covering heart, stroke and metabolic diseases. You can reach Liz on Signal at LizC.22.

Love it or hate it, BMI is in the news again. But that’s just the starting point for the debate over the definition of obesity.

Critics have long charged that the weight divided by height squared measure is too simplistic for defining obesity. Using body mass index (BMI) or body mass index alone, we can ignore population differences and place people with excess muscle mass into the same bucket as people with excess fat. More than a year ago, the Lancet World Commission on Diabetes and Endocrinology aimed to redefine obesity, relying more on consensus measures such as waist circumference, waist-to-hip ratio, or waist-to-height ratio, rather than BMI.

What was new in the committee’s framework was that it drew a clear line between preclinical obesity and clinical obesity, with the goal of more accurate diagnosis starting with BMI and other body fat measurements. People with preclinical obesity have excess body fat and may be at risk for cardiovascular disease, type 2 diabetes, some cancers, and other signs of organ dysfunction, but they have not yet been diagnosed. People who are clinically obese may already have an ongoing disease.

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