Even though new research suggests BMI may be an inaccurate measurement of health. 

By Grace Elkus
Updated February 04, 2016
Jamie Grill/Getty Images

Researchers have long found fault with using a person’s BMI, or their body mass index, as the primary indicator of their health. And new research published in the journal International Journal of Obesity provides even more evidence that the measurement may be inaccurate, finding that tens of millions of Americans are incorrectly labeled as “unhealthy.”

Using data from the 2005-2012 National Health and Nutrition Examination Survey, researchers at the University of California studied the link between an individual’s BMI, which is a measure of body fat based on height and weight, and multiple other health markers, such as blood pressure, cholesterol levels, and insulin resistance. They found that nearly half (47.4 percent) of individuals who are considered overweight by BMI standards are metabolically healthy, as are 29 percent of those labeled as obese and 16 percent of obesity type II/III individuals. In all, researchers say more than 54 million Americans are incorrectly labeled as “unhealthy.”

“Many people see obesity as a death sentence,” Janet Tomiyama, the lead author of the study, said in a statement. “But the data shows there are tens of millions of people who are overweight and obese and are perfectly healthy.”

Unhealthy individuals are incorrectly identified as well. More than 30 percent of Americans whose BMI falls into the “normal” range are unhealthy based on other measures of health.

A rule proposed in April by the US Equal Employment Opportunity Commission makes these findings particularly concerning. The rule would allow employers to raise the health insurance costs for employees that fail to meet certain health standards, such as having a BMI of 24 or lower, by up to 30 percent.

“There are healthy people who could be penalized on a faulty health measure, while the unhealthy people of a normal weight will fly under the radar and won’t get charged more for their health insurance,” said Tomiyama. “Employers, policy makers and insurance companies should focus on actual health markers.”