BMI can accurately measure the difference between weight from fat and weight from lean tissue.

BMI only takes into consideration a person's weight and height, it does not differentiate between weight from fat and weight from lean tissue. As a result, athletes or individuals with a high amount of muscle mass may have a high BMI but a low body fat percentage, while individuals with a low amount of muscle mass but high body fat may have a low BMI but a high body fat percentage.