The American Medical Association is pushing back on the body mass index (BMI) — an easy-to-quantify metric based on weight and height — calling it an imperfect, imprecise way to predict a person’s health.

The AMA also says that BMI should not be used as a “sole criterion” for insurance companies to “deny appropriate insurance reimbursement.”

At the 2023 AMA Annual Meeting held in Chicago from June 9 to 13, the association’s House of Delegates adopted a new policy on BMI, intended to clarify how the measurement can be used in medicine. A report from the AMA’s Council on Science and Public Health said that BMI is an “imperfect way to measure body fat in multiple groups, given that it does not account for differences across race/ethnic groups, sexes, genders and age-span.”

BMI, as a measurement, was founded upon “previous generations of non-Hispanic white populations,” the AMA said in a press release. Additionally, the report says that using BMI can prove problematic “when used to diagnose and trat individuals with eating disorders,” because it doesn’t account for the full range of disordered eating.

Rather, the AMA recommends a handful of additional measurements be used alongside BMI, including metrics accounting for visceral fat, body composition, relative fat mass, waist circumference and genetic or metabolic factors.

The term “Body Mass Indes” was coined in the 1970s, and it was an adjustment to tables published by Metropolitan Life Insurance Company. The MetLife tables, of the average body weights for heights by gender, at different ages, were based on data taken from the mid 1930s to the 1950s, from more than 4 million adults — most of whom were men. BMI attempted to correct that to reduce the effects of body part measurements and in the decades since, many observers have wondered aloud if its outlived its usefulness.

In 2015, an article published in the scholarly journal Nutrition Today said that BMI “has been useful in population-based studies” but has found it to be lacking as a “rather poor indicator of percent of body fat.”

Moreover, it criticizes BMI, when used to correlate with mortality rates, for not taking family medical history into account, as well as other personal habits.

“The BMI was not originally developed for use specifically as an index of fatness in population-based studies. However, it has been coopted for this use because it is a readily obtained metric,” the article said. “It should be understood that the BMI has serious limitations when used as an indicator of percent of body fat mass. Indeed, it may be misleading in this regard, particularly in men.”

The AMA would agree, while acknowledging that there’s no alternate “good reference data” for children, making BMI-for-age the only standard.

“There are numerous concerns with the way BMI has been used to measure body fat and diagnose obesity, yet some physicians find it to be a helpful measure in certain scenarios,” said AMA Immediate Past President Dr. Jack Resneck. “It is important for physicians to understand the benefits and limitations of using BMI in clinical settings to determine the best care for their patients.”

The AMA also added that BMI should not be used as the only reason for insurance to reimbursing policyholders — which insurance providers will use to adjust peoples’ policies.