American Medical Association Finally Drops Support of the BMI

It seemed improbable, but after decades of supporting the use of body mass index (BMI) to assess individual health, the American Medical Association has declared the measurement insufficient and imperfect. In addition, the AMA has for the first time acknowledged the racist history of the BMI, admitting that its continued use is especially problematic due to variations in body types among racial and ethnic groups, as well as different age and gender groups. Also—and I truly cannot believe I am writing this—the AMA is supporting increased training in schools to promote the early identification of disordered eating behaviors.

Most of us are familiar with the BMI from our doctor’s office: You step on the scale, they take your height and weight, and then through some mathematical nonsense and the use of a color-coded chart on the wall, the doctor categorizes your body as either “normal weight,” “overweight,” or “obese.” This determination is the basis for many health recommendations, diagnoses, and—as is far too often the case for people in larger bodies—judgmental and deeply stigmatizing conversations. The BMI, which is just your weight in kilograms divided by your height in meters squared, has been used for decades to justify the worst assumptions about weight and size while ignoring the many environmental, socioeconomic, genetic, and individual factors that determine a person’s health. It’s also caused health care providers to overlook disordered eating behaviors in patients who may not superficially conform to narrow perceptions of what an eating disorder looks like.

This week, the American Medical Association announced that while the BMI is correlated with individual body fat (i.e., people with higher weights probably have more fat), it is “an imperfect measure.” Furthermore, according to a recent report from the AMA Council on Science and Public Health, “the current BMI classification system is misleading about the effects of body fat mass on mortality rates.” Basically, they’re saying what many advocates, therapists, dietitians, and fat liberationists have been saying for decades: being fat is not inherently unhealthy. And when it comes to people with eating disorders, the BMI is really unhelpful. Per the report:

Numerous comorbidities, lifestyle issues, gender, ethnicities, medically significant familial-determined mortality effectors, duration of time one spends in certain BMI categories and the expected accumulation of fat with aging are likely to significantly affect interpretation of BMI data, particularly in regard to morbidity and mortality rates. Further, the use of BMI is problematic when used to diagnose and treat individuals with eating disorders because it does not capture the full range of abnormal eating disorders.

The AMA’s House of Delegates has adopted new policy guidelines for physicians that acknowledge the limitations of BMI because:

• Of the historical harm of BMI.
• Of the use of BMI for racist exclusion.
• BMI cutoffs are based primarily on data collected from previous generations of non-Hispanic white populations and does not consider a person’s gender or ethnicity.

BMI has become so common, yet most people are unaware of its origins and intended use. For a more detailed exploration, I highly recommend Fearing the Black Body: The Racial Origins of Fat Phobia by Sabrina Strings. Briefly: The BMI was developed by a Belgian statistician, mathematician, and astronomer (okay, girl boss!) to describe body size among a population group. His measurements and the subsequent BMI chart are primarily based on white European men from the 1800s. In the 1950s and 1960s, when insurance companies were looking for ways to estimate mortality risk, they revived the BMI.

Since then, the BMI chart has only been updated once: In 1998, the thresholds for overweight and obesity were reduced. When there’s talk of the “drastic” increase in fat Americans in the late ’90s and the so-called “obesity epidemic,” no one acknowledges this crucial change in the BMI chart at the time, which reclassified entire groups of people.

The AMA is now acknowledging that not only is the BMI a flawed measure of health, but that it excludes important individual factors such as variations in body composition among different racial and ethnic groups, sexes, genders, and ages:

• BMI is significantly correlated with the amount of fat mass in the general population but loses predictability when applied on the individual level.
• Relative body shape and composition heterogeneity across race and ethnic groups, sexes, genders and age-span is essential to consider when applying BMI as a measure of adiposity.
• The use of BMI should not be used as a sole criterion to deny appropriate insurance reimbursement.

Finally, the AMA’s new policy supports new research and education initiatives aimed at a more holistic view of health measures and the use of “alternative measures” for “diagnosing obesity.” Look, no one is perfect, and the AMA’s announcement unfortunately still emphasizes other physical measurements while perpetuating the idea that obesity is a disease (it is not; for an expert explanation, read Ragen Chastain’s blog post on the subject).

The AMA’s House of Delegates also modified the current policy on eating disorders and treatment, pushing for more education to help school administrators and officials identify disordered eating behaviors among students and refer them to the appropriate resources for support. The delegation is calling on the AMA to:

• Encourage training of all school-based physicians, counselors, coaches, trainers, teachers and nurses to recognize abnormal eating behaviors, dieting and weight-restrictive behaviors in children and adolescents and to offer education and appropriate referral of adolescents and their families for evidence-based and culturally informed interventional counseling.
• Consulting with appropriate, culturally informed educational and counseling materials pertaining to abnormal eating behaviors, dieting and weight-restrictive behaviors.

Emphasizing cultural awareness is crucial, as people—and especially women—of color with eating disorders are historically underdiagnosed. The Diagnostic and Statistical Manual of Mental Disorders, or the DSM, has narrow criteria for diagnosing eating disorders. While these criteria have improved somewhat over time, the criteria for diagnosing anorexia in particular is problematic. An individual must be underweight to meet the criteria for an anorexia diagnosis, and the BMI is used as the basis of this determination. Those with anorexia who are not underweight are classified as “atypical” anorexics, which can lead to problems with obtaining insurance coverage for their treatment.

Under the AMA’s new policy guidelines, there’s a stronger argument to be made for updating the DSM’s criteria for eating disorder diagnoses. And, by declaring that the BMI should no longer be used as the “sole criterion” in insurance coverage, it’s possible that more people will be able to access the care they need—with a little less stigma attached. Like the BMI itself, the AMA is imperfect, but at least one of these things is attempting to make itself more useful.

(featured image: Getty Images)