It used to be that to determine how fat a person was one took calipers and took anywhere from three to seven measurements of the body, came up with a total, and looked at a chart that took age into account to come up with a number for body fat percentage. That might that a few minutes or a little longer if you did as recommended and checked it twice to make sure.
Now BMI is the preferred measurement. Take weight and height and look at a chart – you’re done, let’s golf.
In his prime fighting weight Mike Tyson was 5’10’ and 220 pounds. According to BMI charts Mike's BMI of 31.6 would classify Mike as clinically obese. BMI is wildly inaccurate. Why is it used? It is easy, that is why. It takes few seconds instead of a few minutes. What is worse, researchers base studies on the BMI.