A new University of Florida Health study has cast serious doubt on the long-trusted body mass index (BMI) as a reliable predictor of long-term health risks, including mortality.
The research, published in The Annals of Family Medicine, suggests that BMI fails to predict a person’s risk of dying, including from heart disease. It calls for BMI’s replacement with a more accurate method: bioelectrical impedance analysis (BIA).
Unlike BMI, which is calculated using height and weight, bioelectrical impedance analysis (BIA) directly measures body fat using a mild electrical current.
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According to the study, individuals with high body fat, measured via BIA, were 78% more likely to die of any cause and 3.5 times more likely to die of heart disease over 15 years. By contrast, BMI showed no significant link with mortality.
“This is a game-changer,” said lead author Dr Arch Mainous. “BMI failed. It’s time for healthcare to move on.”
The study analysed more than 4,200 people over 15 years. The researchers argue that BIA, while not as precise as DEXA scans (the gold standard), offers a practical and far superior alternative to BMI in everyday clinical settings.
Critics of BMI have long noted its limitations: it doesn’t account for muscle mass, age, gender, or fat distribution. It can misclassify athletes as obese and overlook people with high fat but normal weight.
“This study proves what we’ve suspected for years,” said Dr Frank Orlando, senior author. “BMI isn’t a one-size-fits-all indicator, and it never should’ve been treated like one.”
