Move over, body mass index — make room for the body roundness index. The body mass index (BMI) is a ratio of height to weight that has long been used as a medical screening tool. It's one of the most widely used health metrics but also one of the most reviled, mainly because it's used to label people overweight, obese, or extremely obese. One major criticism 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. Because muscle is much denser than fat, BMI skews higher in people who are very muscular but have less body fat. On the other end of the spectrum, BMI can be underestimated in older people with much less muscle mass and more body fat. The body roundness index (BRI) is a more precise way to estimate obesity. BRI incorporates hip and waist circumferences to estimate how much total fat and visceral fat —a type of deep belly fat that surrounds the organs and can be more harmful to health — someone has. Where BRI makes a big difference is in allowing for more variation, which can better tease out how much of a person’s body is fat. BRI isn’t a perfect measurement — it still isn’t able to calculate a person’s muscle mass, which plays a big role in health — but it’s more realistic than BMI.
Time To Say Goodbye To the BMI?
Move over, body mass index — make room for the body roundness index. The body mass index (BMI) is a ratio of height to weight that has long been used as a medical screening tool. It's one of the most widely used health metrics but also one of the most reviled, mainly because it's used to label people overweight, obese, or extremely obese. One major criticism 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. Because muscle is much denser than fat, BMI skews higher in people who are very muscular but have less body fat. On the other end of the spectrum, BMI can be underestimated in older people with much less muscle mass and more body fat. The body roundness index (BRI) is a more precise way to estimate obesity. BRI incorporates hip and waist circumferences to estimate how much total fat and visceral fat —a type of deep belly fat that surrounds the organs and can be more harmful to health — someone has. Where BRI makes a big difference is in allowing for more variation, which can better tease out how much of a person’s body is fat. BRI isn’t a perfect measurement — it still isn’t able to calculate a person’s muscle mass, which plays a big role in health — but it’s more realistic than BMI.