How is FMI (Fat Mass Index) different than BMI?

Unlike body mass index (BMI), fat mass index (FMI) is a gender-specific measure of fat that takes into account lean mass.

BMI does not reflect true body fat composition and has limitations in assessing people with low muscle and high body fat or increased body fat and normal BMI.

Fat mass index is able to identify individuals with elevated BMI but without excess fat mass — such as strength athletes. Conversely, FMI can also identify individuals with normal BMI, but who are at potential risk because of elevated fat mass.

Studies show FMI is a better screening tool for predicting the presence of metabolic syndrome than BMI in men and women.