To quantify, I've heard MDs say that the outliers (relatively high BMI but low body fat) constitute less than 1% of high BMI people. They also said that those o

To quantify, I've heard MDs say that the outliers (relatively high BMI but low body fat) constitute less than 1% of high BMI people. They also said that those outliers are still at risk of certain health troubles, like sleep apnea. The suggestion of using BMI + waist circumference is an easier to measure risk factor than bodyfat percentage and helps to better capture those outliers.