BMI Is Problematic. Is Body Roundness Index Any Better?

If the term body mass index (BMI) sends a shudder of anxiety down your spine, you're not alone. The test — meant to measure a person's body fat based on their height-to-weight ratio — has been used as an indicator of health since the 1970s. However, more recent research has revealed BMI to not only be an insufficient measure of health, but also highly problematic, with initial studies almost exclusively made up of Caucasian men.

In pursuit of a new and more accurate measure, body roundness index (BRI) has entered the chat with some splashy new studies to back it (more on that in a second). So what is BRI and is it truly better than BMI? Experts say the answer is complicated. While BMI is calculated using weight and height, BRI uses height and measurements like waist circumference (no weight required). The theory is that this new equation serves as a more reliable predictor of health and mortality, but there's still some important caveats to consider. Read on to find out more about BRI, including whether or not it's actually better than BMI — according to doctors.

Experts Featured in This Article:

Natasha Bhuyan, MD, is the vice president of in-office care at One Medical.

LaTasha Seliby Perkins, MD, is a family physician and assistant professor of Medicine at Georgetown University.

What Is BRI?

"BRI stands for body roundness index — a measurement that may predict health risks," says Natasha Bhuyan, MD. BRI is a potential indicator of health that can be determined using the formula: 364.2 − 365.5 × √(1 − [waist circumference / 2π]2 / [0.5 × height]2. You can use any unit of measurement (centimeters or inches), so long as it remains the same throughout the entire equation. Per the New York Times, BRI typically ranges from one to 15 (although this varies depending on the exact calculator you use) — although most people score between one and 10.

According to Dr. Bhuyan, BRI recently garnered attention after a study published in the journal "Nutrition, Obesity, and Exercise" found that those with a higher BRI had an increased risk of mortality. This same study found that the risk of mortality followed a U-shaped trend, increasing by 25 percent for participants with a BRI of less than 3.4, and by 49 percent for those with a BRI of 6.9 and above. In this study, people with a BRI between 4.5 and 5.5 were found not to have an increased risk of mortality, making this the ideal BRI range.

How Is BRI Different From BMI?

BRI uses different measurements than BMI, most notably excluding weight. "BMI only takes into account someone's height and weight," explains LaTasha Seliby Perkins, MD. BRI, on the other hand, uses height and waist circumference. "BRI removes weight from its underlying calculation. Instead, the focus is on abdominal belly fat, which is linked to conditions like diabetes and high blood pressure," Dr. Bhuyan says.

Because of the way it's measured, BRI can also account for differences in weight distribution, which may help determine certain health risks and conditions, Dr. Perkins adds (such as lipedema, which is often characterized by increased fat in the lower body).

Is BRI Better Than BMI?

In many ways, yes. "Because waist circumference and body fat distribution is a part of BRI, in some ways it's better to indicate health risks than BMI," Dr. Perkins says. "Mortality risks will be connected to fat distribution around your organs."

We also know that BMI can be problematic when used as an indicator of health because it tends to oversimplify important details. A professional athlete, for example, could have a higher BMI despite their extremely active lifestyle, due to increased muscle mass. "BMI has always been an imperfect measurement of health. It does not factor in someone's muscle mass, race or gender," Dr. Bhuyan says, noting that BMI was created based on majority European male populations. That said, BRI isn't necessarily a perfect solution.

"While BRI is likely better than BMI, it's also still not a comprehensive reflection of someone's health," Dr. Bhuyan says. For instance, it doesn't take into account hormonal changes (which can increase belly fat), aging, or environmental factors like stress, and stable housing, all of which have an effect on health. "Health is complicated — it includes our genetics, sleep patterns, activity, eating habits, stress, vitals, social determinants of health, and many other biomarkers," Dr. Bhuyan says.

What to Keep in Mind

Dr. Perkins notes that, while she's started using BRI in her own practice, it's still a relatively new measure of health. "When it comes to measuring your health using indicators like BRI and BMI, it's important for you to discuss with your family doctor," she says. They can provide guidance if you're not sure which is best for you.

Dr. Bhuyan also acknowledges that for some, measurements like these may feel too triggering. "We are moving from one focus on the body (weight) to another (waist)," she says, referencing the difference between BMI and BRI, respectively. "A holistic approach to health is certainly more complicated but also more accurate," Dr. Bhuyan says — think markers related to sleep, diet, and stress, all of which can help us see the full picture when it comes to our health. "We want simple and snappy stats about health — and [most of the time] it just doesn't work that way," she says.

Chandler Plante (she/her) is an assistant health and fitness editor for PS. She has over four years of professional journalism experience, previously working as an editorial assistant for People magazine and contributing to Ladygunn, Millie, and Bustle Digital Group.