BMI is not enough to assess weight and health; understand – 06/20/2023 – Equilibrium

The American Medical Association has approved the adoption of a recommendation that encourages physicians not to rely solely on BMI (body mass index), a long-used but potentially misleading metric to assess weight and health. The guideline officially acknowledges the “historical harm” of the BMI and states that the metric was used “for racist exclusion”.

“It’s a very big shift,” says Cynthia Romero, director of the M. Foscue Brock Institute for Community and Global Health at the Eastern Virginia School of Medicine, who participated in the development of the US guideline. “Now we have to be really more aware and more holistic when it comes to patient care.”

The action could be a first step toward abandoning a model of medicine that urges people above a certain BMI to lose weight, without regard to the toll these weight-loss measures can take, says Scott Hagan, assistant professor of medicine at University of Washington, which has studied obesity and did not sign the recommendation. “It’s really, really important,” he says.

While the association is influential in the medical community, the new indication is only a suggestion for physicians, not a strict rule they must abide by.

The body, one of the largest medical groups in the US, will now recommend that doctors not only use BMI to assess whether a patient is at a healthy weight. They suggested that doctors also consider factors such as the person’s visceral fat (that stored in the abdominal cavity and around the organs); body adiposity index (calculation using hip circumference and height); the percentage of fat, bone, and muscle in the body; and genetic and metabolic factors, such as abnormal blood sugars or thyroid tests.

BMI is a simple calculation with a complicated background. It is obtained by taking a person’s weight in kilograms and dividing it by the square of their height in meters. Critics have long argued that it is an inaccurate measure of health, as someone with a lot of muscle and little fat can have the same indica as a person with obesity.

“BMI is just a very poor measure of overall health,” says Hagan. “Someone with a high BMI may be perfectly healthy.”

And where you carry the weight matters, says Leslie Heinberg, director of the Cleveland Clinic’s Enterprise Weight Management Center. Abdominal fat is associated with higher rates of type 2 diabetes and cardiovascular disease, compared with fat around the hips, she says, a nuance the metric fails to capture.

“There are numerous concerns with the way BMI has been used to measure body fat and diagnose obesity, but some clinicians feel that it is a useful measure in certain settings,” wrote Jack Resneck Jr., who stepped down, in a statement. association president this month, adding that practitioners should understand the benefits and limitations of the metric.

At a population level, BMI is “probably the best we can do” in assessing large groups of people, says Iliya Gutin, program officer for the National Academies of Sciences, Engineering, and Medicine and research affiliate at the University of Texas at Austin, who also studied the metric and said it applauds the new recommendation. It is also cheap and efficient.

But BMI “isn’t this magic or powerful number that determines how healthy or sick someone is going to be,” says A. Janet Tomiyama, a professor of psychology at the University of California at Los Angeles who has studied the metric and says she was “in shock. ” about the new policy.

“For a long time I was in this emperor with no clothes situation where I just couldn’t understand why really smart doctors kept relying on something that is so clearly so flawed.”

The new statement also highlights that BMI was based primarily on data drawn from previous generations of non-Hispanic whites, making it difficult to apply the measure to a broader population.

Despite resistance against the suggestion, it remained widely used.

“Many of our standards and guidelines were built around it,” says Gutin. “When that happens, it’s very difficult to change inertia.”

Translated by Luiz Roberto M. Gonçalves