Body mass index has long determined what it means to be overweight. Invented in the early 1800s by a Belgian statistician, the measurement is used as a definitive benchmark: those with a score below 18.5 are underweight, those who fall between 18.5 and 24.9 are normal, those between 25 to 29.9 are overweight, and those 30 and higher are obese.
For years, medical professionals have taken issue with these cleanly drawn lines. The BMI scale, critics argue, is too simplistic to accurately reflect health on an individual basis.
Today, the Mayo Clinic adds its voice to the chorus. The medical care provider announced that is recommending a new system for measuring body composition and weight distribution: the Body Volume Indicator (BVI). Unlike BMI, which is formulated by comparing an individual’s weight in relation to his or her height, BVI considers “other crucial factors such as fat mass, lean mass, and weight distribution when determining an individual’s body composition,” Jose Medina-Inojosa, a cardiovascular research fellow at the Mayo Clinic, told Fortune. In addition to weight and height, information on waist-to-hip ratio, total body fat percentage, and abdominal volume is factored when determining a score.
These are harder metrics to measure than feet and pounds, of course, but technology has advanced since the 19th century. Select Research, a U.K.-based market research agency and pioneer in 3D body measurement, in cooperative development with Mayo Clinic, has launched an app to help people measure their BVI.
Here’s how it works: doctors take two photos of their patients, wearing just their underwear, from the front and from the side. After the photos are taken, they are turned into 3D body silhouettes, and sent to a backend server where the images are compared to a database compiled from thousands of MRI images, 3D body scans, and Cadaver information. (The photos themselves are then deleted.)
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By cross-referencing 3D silhouettes of patients with this database, the app provides more detailed information on weight distribution and volume, particularly for the abdomen, the area of the body “associated with the greatest risk for metabolic disease and insulin resistance,” said Medina-Inojosa. An increasing body of research suggests that fat in the midsection, which blankets the organs, is associated with a higher likelihood of premature mortality than fat carried in other areas of the body. Two women could be the same weight and height, but if one carries most of the weight in her hips, while the other’s is distributed primarily in the stomach, the latter would be at greater risk of developing a host of health issues. Their BMIs would be identical, but because BVI considers weight distribution and the percentage of fat stored in the abdominal cavity, those numbers would be different.
Not only does BVI serve as a more granular measurement, but Medina-Inojosa believes it can also be used as a tool to improve motivation and accountability; it’s possible to gain muscle and change one’s overall body shape, without seeing a similar shift in BMI.
Most importantly, however, he hopes a new system will help people realize that “obesity is a complex disease not only defined by weight.” He’d like to see the conversation move beyond a fixation on pounds gained and lost.