The 'Body Roundness Index' Is Touted As The New BMI — And It's Got A Big Problem
ICYMI, determining someone’s health by checking their body mass index is … well, not it.
For decades, BMI was used as a major indicator of one’s health. But recently, the American Medical Association decided to adopt a new policy on BMI because it doesn’t account for differences across race, gender, age and other demographics. Further, BMI doesn’t differentiate between fat and muscle mass — it just suggests that a person weighing over a certain amount is unhealthy.
Researchers have recently looked at not only weight and height, as BMI does, but also waist circumference and hip circumference. Those numbers are then used to estimate the risk of disease and mortality. This measure is called the “body roundness index,” or BRI.
Though a 2024 study in JAMA Network Open suggested that BRI was superior to BMI, a number of health care providers believe it’s still flawed.
“Even with these two additional data points, BRI is extremely oversimplified,” said Christine Byrne, a registered dietitian in Raleigh, North Carolina. In a previous article for HuffPost, she wrote about BMI’s racist roots and scientific inaccuracies — problems that critics in the medical community also see with BRI.
To put it even more bluntly: “Can we just stop measuring people’s bodies, please?” asked Dr. Jennifer Gaudiani, the founder and medical director of the Gaudiani Clinic in Colorado. “It’s a lazy way of not asking them questions about their actual lived experience and measuring health markers directly. It distracts us into a belief of individual responsibility and willpower, when we must be looking at systems.”
“In the same light [as BMI], the BRI has the potential to be harmful, as it can also lead to discriminatory interventions among diverse populations,” said Dr. Elizabeth Wassenaar, a regional medical director at the Colorado-based Eating Recovery Center.
Let’s dive deeper into that and other concerns that doctors and dietitians have about BRI.
It’s basically the same thing as BMI.
While “BRI” is one letter different from “BMI,” the two measures are essentially the same.
“Nearly all of the concerns that people have with BMI are still relevant with BRI,” Byrne said. “Both use body shape and weight to make big guesses about someone’s health status and disease risk, without looking at any other markers of health, metabolic syndrome or other diseases.”
She believes health care providers still use BMI for two reasons: It’s simple and inexpensive.
“Favoring simplicity doesn’t necessarily come from an evil place — there are limited resources in health care, and providers often don’t have tons of time to spend with patients, through no fault of their own,” Byrne validated. “But that doesn’t mean the BMI or BRI are accurate measures of health. In fact, they’re really stigmatizing and inaccurate.” (More on that ahead.)
It conflates correlation with causation.
From a scientific standpoint, BRI has holes. The JAMA Network Open study showed an association between BRI and all-cause mortality, but that only means so much.
“Correlation means there is a relationship, but it can’t be concluded that there is 100% a direct relationship,” said Dr. Gregory Dodell, an endocrinologist at New York’s Central Park Endocrinology.
“It is a reductionistic association,” Wassenaar agreed. “Both BMI and BRI assume that if we reduce these numbers, we reduce mortality, and the data simply doesn’t reflect that. … This is aggregate data, which means that trends were observed, not individual changes and outcomes.”
It doesn’t take some huge factors into account.
Along the lines of how correlation doesn’t mean causation, Gaudiani said the issue is Western medicine incorrectly interpreting data.
“You don’t look at a cohort of folks who grew up in polluted environments (smog, smoking), assess their lung capacity and decide: ‘This person has a high gray lung index. They need to make their gray lungs more pink through hard work and willpower,’” she said. “They need to back the camera up and recognize how the environment contributed to lung function, and address the environment rather than the individual lungs and their color.”
That’s an example of the social determinants of health, which include five domains: economic stability, education access and quality, health care access and quality, neighborhood and built environment, and social and community context. These factors play a large role in our health.
Those determinants were not emphasized in the 2024 BRI study, in which some of the most marginalized populations were suggested to be relatively unhealthy. The results indicated that Mexican Americans, Black Americans, older adults, women and individuals with lower socioeconomic status have higher BRIs, suggesting higher rates of all-cause mortality. But that is too simplistic.
“We know that Black and Latino(a) populations have higher rates of death due to health disparities, including the lack of access to timely and appropriate health care, leading to poorer health outcomes and premature death,” said Dr. Erikka Taylor, a double board-certified psychiatrist with the group Project HEAL who serves on the race, ethnicity and equity committee for the North Carolina Psychiatric Association. “The BRI does not account for hormonal changes or changes in muscle mass, bone density or differences in fat distribution due to age or hormonal shifts. … There is a lot of data showing that poverty and limited access to education lead to worse health outcomes, including lack of access to care, delayed treatment and poor quality of care.”
When it comes to the “roundness” part of BRI in particular (cringe), Wassenaar said that central adiposity reflects inflammation and trauma, and that no single number can measure someone’s health.
“Focusing on the size of someone’s abdomen undermines the reality that body diversity has existed throughout time and a wide variety of bodies can have health,” she said. “They deserve support and healing beyond what any number can measure.”
Further, antifat bias and fat-shaming can play a role in health outcomes that are often attributed, inaccurately, to weight alone.
“People at a higher BRI may have a higher associated mortality due to the impact of weight stigma, which has been shown to have detrimental mental and physical consequences (substance abuse, eating disorders and avoidance of medical care),” Dodell said.
It’s used to define health, and it can’t.
Some folks go to the doctor and their health is quickly assumed after stepping on the scale — or worse, with one glance. People in larger bodies have reported receiving inadequate care in doctor’s offices, where “lose weight” is often the prescription.
“Many people with low BRI and many people with high BRI are still perfectly healthy,” Gaudiani said. Like many providers, she abides by the Health at Every Size framework, which puts less emphasis on weight as way to assess health.
And health isn’t easily definable, anyway. What’s healthy for one person may look different from what’s healthy for another, depending on their medical history.
“[Health] involves the achievement of certain measurable parameters that may not be someone’s choice for themselves. Or if it is, it may be wildly out of reach due to many other factors, including resources, ability, race, ethnicity, environment, etc.,” Gaudiani added.
Think of the disabled person who can’t move in the same ways as nondisabled people, or the person who lives in an environment impacted by wildfire smoke. They aren’t any less-than, and yet moralizing health can suggest that.
Looking at certain lab markers may be more helpful— or at least more than external markers. “These measurements do not take internal health assessments like cholesterol, inflammatory markers or blood sugars into consideration,” said Maya Feller, a certified dietitian nutritionist in New York. “Solely relying on external markers leaves significant room for misclassification and error, not to mention the additional stigma directed toward larger bodies.”
It could actually cause more harm.
In addition to an avoidance of medical care — because it can be a frustrating experience for people living in larger bodies — and BRI’s similarities to BMI, there is yet another problem: how the measure may negatively impact someone’s relationship with their body and food.
“I suspect that the process of having a waist circumference measured and discussed may be additionally triggering for people with eating disorders, body dissatisfaction and/or have experienced weight stigma,” Dodell said.
That, in turn, can contribute to negative health outcomes and shame that’s nothing short of a nightmare.
Here are alternative ways to assess and address your health.
Your health and body size aren’t totally in your control; they can be affected by tons of factors, such as discrimination, trauma, access to various foods and ways to exercise, and literacy skills. In fact, Byrne said that when it comes to body size, genetics and environment play a larger role than food and physical activity.
“Genetics plays a significant role in our body habitus,” Dodell said. “The concern is that [BRI] ... may be another means whereby assumptions are made. It is important to note that weight is not a behavior.”
So, what is in your control? These experts recommended eating a variety of foods; managing your stress; moving your body in fun, feel-good ways; getting routine health screenings; and getting enough solid sleep. Assessment markers include blood pressure, cholesterol levels and other lab values.
If you’d like more support and knowledge around food and nutrition, consider working with an antidiet dietitian who “can help you craft a personalized nutrition plan that takes you and your whole life into consideration,” Feller said.
Wassenaar believes in focusing on personal goals that enhance your life. If you want to be able to play outside with your children, for example, she suggested working on your cardiovascular endurance and balance, as well as buying good walking shoes.
“These are discrete things that you can work on to improve your quality of life which allow you to be part of the process of creating a life worth living,” she said.
You can also contribute to macro changes for those who are less fortunate and have been marginalized. Taylor shared examples such as improving access to quality health care and addressing social determinants of health. On an individual level, that might include raising awareness about these issues, voting, donating to mutual aid funds or taking an unconscious bias training.
“The reality is, our bodies are complex,” Wassenaar said. “They reflect so many things about who we are, who we were and the generations before us that brought us to today. To reduce life to a single number, about a single body part, is reflective of an ongoing problem: that our current understanding and working with humans reduces them to numbers in a medical chart.”
Need help with substance use disorder or mental health issues? In the U.S., call 800-662-HELP (4357) for the SAMHSA National Helpline. If you’re struggling with an eating disorder, call or text 988 or chat 988lifeline.org for support.
