Bmi provides common language for doctors, dietitians and agencies like insurance companies to use as a method to determine an individual's body weight and risk for diseases like diabetes.

BMI (body mass index), which is based on the height and weight of a person, is an inaccurate measure of body fat content and does not take into account muscle mass, bone density, overall body composition, and racial and sex differences.  BMI is a substitute measure of body fatness because it is a measure of excess weight rather than excess body fat. Factors such as age, sex, ethnicity, and muscle mass can influence the relationship between BMI and body fat.