BMI has its flaws. Is the ‘body roundness index’ any better?

New research points to a better way to measure obesity than body mass index. Body mass index was first developed in 1832 and has been the standard way to estimate a person’s body fat since the 1980s. The calculation, however, has come under increasing scrutiny in recent years.

One major critique of BMI is that it doesn’t look at how much of a person’s weight is fat, and where fat is distributed around the body. It also doesn’t take into account the other elements that make up a person’s body composition beyond fat, including muscle, bone, water and organs. “Fat distribution and body composition can vary dramatically among different people with the same BMI,” Wenquan Niu, a professor at the Capital Institute of Pediatrics in Beijing, wrote in an email.

Because muscle is much denser than fat, BMI skews higher in people who are very muscular but have less body fat, like athletes, Niu said. On the other end of the spectrum, BMI can be underestimated in older people with much less muscle mass and more body fat. In a study published last week in JAMA Network Open, Niu and his colleagues showed that a different measurement, called the body roundness index, is a more precise way to estimate obesity.

While BMI estimates a person’s body fat using just two measurements, height and weight, BRI also incorporates hip and waist circumferences to estimate how much total fat and visceral fat someone has. Visceral fat is a type of deep belly fat that surrounds the organs and ca.