Why Body Mass Index Is a Historically Flawed Health Standard for People of Color

BMI has been integrated into the U.S. healthcare system for decades, but experts explain that the standard did not historically consider people of color

healthcare worker explaining to young patient in medical clinic
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The use of body mass index, or BMI, has been integrated into the United States healthcare system for decades, and experts are speaking up about it being a flawed standard of health, specifically for people of color.

BMI is calculated based on a person's height and weight, and the number is used throughout the healthcare system — including by the World Health Organization and National Institutes of Health — to sort people into four categories: underweight, healthy, overweight or obese. It's a formula: a person's weight (in kilograms) divided by the square of their height (in meters).

However, BMI was developed in the mid-19th century by a white Belgian mathematician named Adolph Quetele — during an era when pseudoscientific theories were created to maintain nationalism and racism. The "ideal" measurements for BMI are based on problematic racial and societal biases as Quetele did not consider a person's ethnicity, gender or body makeup, using a sample of only white, European men to create the index.

Research has shown that the BMI that is considered "obese" — 30 or over — is simply not true of everyone.

A large 2003 study found that higher BMIs are not unhealthy for Black people, and Black women in particular do not see an increased mortality risk until they reach a BMI of 37 (32 for Black men). Yet, based on BMI, doctors often diagnose them with obesity, high blood pressure and diabetes, and stigmatize them for being "overweight."

"[Quetele] actually was somebody who was a big proponent of eugenics and he didn't consider Black people or people who are not white as actual humans," Dr. Heather Irobunda, a New York-based OB-GYN, tells PEOPLE. "So this was a way to classify specifically white people in these categories of underweight, normal, overweight, obese. And that's why it's troublesome because it didn't utilize the whole population to derive this."

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doctor taking patient's blood pressure

"And [health professionals] use these metrics to determine if people are at risk for certain diseases. So things like cardiovascular illness or diabetes," explains Irobunda, who utilizes her platform to share information on biases in healthcare. "People use obesity as a marker for that and use the body mass index to characterize that."

If medical professionals prioritize referring to BMI as a cause of health issues, doctors can misdiagnose patients or overlook other possible diagnoses that result in improper treatment plans.

"For example in my field, OB-GYN, there are some fertility clinics or providers who will deny people to get IVF, or other assisted reproductive technology, because they have a higher BMI," Irobunda notes.

Additionally, after BMI was developed, it was quickly adapted by life and health insurance companies, which has in turn created long-standing health disparities among people of color.

"With certain health insurance companies that cover these things … they may have a BMI cut off. And the thing about it is that when you look at the research and pare it down, it's not necessarily the BMI that's an issue," Irobunda adds.

woman on scale

Moving forward, there is a need for medical professionals to be more cognizant of how weight is distributed and other factors that come into play, experts say. Shifting away from BMI will take time, as it's deeply ingrained in the medical system. Many experts suggest doctors look at waist-to-hip ratio (WHR) as an alternative to BMI.

WHR is calculated when the waist circumference is divided by the hip circumference. For both men and women, a WHR of 1.0 or higher is considered "at risk" for undesirable health consequences, such as heart disease and ailments associated with being overweight, according to the National Institutes of Health. A healthy WHR is reportedly 0.90 or less for men, and 0.80 or less for women.

Carrying a higher amount of weight around the waist can cause a number of health problems. Health is impacted by where body fat is stored, even if an individual's BMI is "normal." According to the American Diabetes Association, WHR is also more accurate in predicting the risks of cardiovascular disease and premature death than BMI.

However, BMI is still used because it's easy and it's by convention, Irobunda says.

"So it's really trying to break that convention because just like putting someone on a scale and taking their height is relatively easy, also doing a waist circumference and a hip circumference isn't that hard to do, either," she continues. "So it's like really trying to break that and then teaching people and showing people the evidence that BMI is not the end all be all in determining someone's health."

Though WHR can be more beneficial or accurate than BMI, there is still conflicting data that can leave unanswered questions for health professionals treating patients with different body compositions.

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Since BMI is still widely used, experts urge individuals — specifically Black patients and other people of color — to be vocal about if they are uncomfortable with their BMI being referred to when being diagnosed or treated.

"If it's something that you have an issue with, be very upfront about it either before you come to your appointment or at the onset of your appointment, saying, 'Hey, I've had some issues in the past that when we do my height and weight or mention my BMI, it triggers that.' That's a reasonable thing to discuss," Irobunda notes. "And you can also ask, 'What is this information going to be used for in terms of my BMI? Is it relevant to the care that I'm going to be receiving today?' Those are all questions you can ask."

"I think that having more frank conversations about why people need to be weighed and why we need to have BMI information, it's good to have between providers and patients."

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