BMI overestimates body fat in bodybuilders and can underestimate fatness in people of normal weight who have little muscle mass, but carry a lot of extra pounds in the midsection. For both of these populations, a measure of waist circumference may be a better indicator of health.

Does BMI apply to weightlifters?

BMI doesn't account for body composition, which means it misses the difference between muscle mass and fat. Because muscles are more dense and heavier than fat, bodybuilders and other professional athletes like football players are often considered obese or overweight based on their BMI alone.

Does BMI Work If You muscular?

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, say researchers from the Perelman School of Medicine, University of Pennsylvania.