Is Body Mass Index Racist Healthcare?

There is little doubt that beauty is culturally constructed. We need to look no further than the women depicted by 15th Century Artist Sir Peter Paul Reubens and what has been held, until recently, as the beauty of slender or thin. There is strong evidence of that cultural impact

“I conclude that fat was a “floating signifier” of race and national belonging. That is, rather than being universally lauded or condemned, the value attached to fatness was related to the race of its possessor.”

The article's author, Dr. Sabrina Strings, a professor of sociology at UC Irvine, places this racialization of fatness in the framework of the late 19^th and early 20^th century push for eugenics – identifying the ideal body and mind for our aspirations. She shows that much concern about fat was driven by insurance companies that often developed standard height and weight tables based on their customers, primarily white males.

She then turns to the work of Ancel Keys, known for the only study of starvation, the Minnesota Starvation Experiment, and the development of K-rations and popularizing the “Mediterranean” diet. She notes, as did Keys in his 1953 review in which he looks at all the available means of measuring fat that

“The practices followed in connection with the use of ‘standard weight’ tables vary in a most confusing way,” as people might be weighed with or without shoes and clothing. For example, to compensate for shoes and clothing, one author “subtracted 10 lb. from the weight and 1 in. from the recorded height of men,” and,  for women, “the standard corrections were 6 lb. and 1.5 in.,” making the women appear on average heavier and shorter than men.”

As with many of the measures we use today, including morphine milligram equivalents in our war on opioids, there is little science in these tables and much scientism – the unwarranted use of science where it may not truly apply.

Dr. Strings ends on this note,

“… if the foregoing discussion reveals anything, it’s that the scientific method was at best loosely and rarely applied in the creation of weight-based health categories, and at worst skirted. Which is to say, obesity science has always been a (racist) form of pseudoscience that relies on statistical correlations based on a limited portion of humanity. Knowing this fact, whatever could be the rationale for keeping it alive?”

On June 13^th, the American Medical Society chimed in,

“…the AMA recognizes issues with using BMI as a measurement due to its historical harm, its use for racist exclusion, and because BMI is based primarily on data collected from previous generations of non-Hispanic white populations.”

They cautioned physicians in applying BMI to their patients, but of course, BMI has always been meant to apply to populations, not individuals. 

Is there an alternative narrative?

While Dr. Strings cites statements that Dr. Keys found obesity “disgusting” and “a health hazard,” that does not reflect racism. But what if we leave all intimations of intent aside and consider the science?

As Dr. Keys alluded to in his 1953 review, measuring “fatness” is quite difficult because it may have many different measures, weight, skin-fold thickness, not to mention sophisticated imaging and measurement of visceral, subcutaneous, brown, and white fat. As our understanding of the association between weight and health has improved, so have our measurements. BMI is not the best measure in all circumstances, but it is clearly better than weight, having taken height into account. Unlike more sophisticated imaging, it has little, if any, cost and is readily performed. BMI is a useful, practical measure in population studies, and none of the protesting voices have offered a substitute.  

Body mass index incorporates height and weight; there is no racism or culturalism in the math. The bias comes from two sources. First, and the most easily corrected, is having a diverse enough population to measure. The standard weight and height tables of white males are insufficient to characterize all ethnicities and cultures. But having said that, biased population samples based upon those same decried social constructs of race continue to be used. The UK Biobank has been cited in over 3000 scholarly articles since 2017 and involves a population that is 88% White. We can correct this by diversifying the participants in these population surveys, but as we are beginning to discover, that is more easily said than done. 

The second bias comes from the application of those measurements. There is no reason that BMI, a continuous variable along a spectrum of values, must be made categorical. The characterization and categorization of BMI into underweight, normal, overweight, obese, and morbidly obese, even when masked by statistical measures, is a human judgment subject to bias. We categorize to simplify our models, and that is part of why “all models are wrong.” At best, we might also create a categorization of BMI for each specified population.  

There is a fundamental conflict between population data and its application to the individual. The most precise care requires a population of one. But to scale a version of that individualized care to the point that it is readily affordable and helpful, population data must be far more significant. Simply recruiting more unrepresented groups is insufficient; after all, Hispanics include 21 countries, each with its own culture, history, genetic similarities, and differences.

BMI was chosen because it provides a more predictive value than weight alone and is easily measured. To ignore our body composition in considering our biological health is misguided, but what do Dr. Strings and the AMA offer in place of BMI? What you are hearing are crickets.

Source: How the Use of BMI Fetishizes White Embodiment and Racializes Fat Phobia DOI: 10.1001/amajethics.2023.535.