A new University of Florida study challenges one of health care’s most common metrics: body mass index (BMI).
Published in Annals of Family Medicine, the research found that BMI doesn’t reliably predict long-term mortality risk — while body fat percentage does.
Using data from 4,252 adults in the National Health and Nutrition Examination Survey, researchers tracked participants for 15 years. Those with high body fat levels, measured using a method called bioelectrical impedance analysis (BIA), were 78% more likely to die of any cause and 3.5 times more likely to die from heart disease. BMI showed no significant link to death from any cause.
“BMI failed,” said lead author Arch Mainous, Ph.D., who compared the findings to a “Coke versus Pepsi” product test. “This study is a game-changer.”
BIA, already used in some doctor’s offices and available in many smart scales, estimates body fat by sending a tiny electrical current through the body and measuring resistance. Unlike BMI, which is based only on height and weight, BIA provides a more direct look at body composition.
The study’s authors, including Dr. Frank Orlando, say it’s time for clinicians to move away from BMI as a standard health screening tool.
“We use BMI to sort of screen for a person having an issue with their body composition, but it’s not accurate for everyone like vital signs are,” Orlando said.
The study was supported by internal funding from the University of Florida Department of Community Health and Family Medicine.
As tools for assessing metabolic health evolve, this research adds fuel to the push for more accurate, individualized measures of risk.