Although this method is a quick and effective body fat measurement, it does have limitations.
The formula is built on statistical averages, meaning any variance from what's considered "normal" can skew the results.
BMI tends to be overestimated in athletes and people with a muscular build.
A bodybuilder who measures 5'11" and weighs 190 lbs would be considered overweight with a BMI of 26.5.
This BMI suggests that this man has too much body fat. But, if he is very muscular, this is actually not the case. He only weighs more because he has more muscle mass, which is an indicator of a healthy body.
On the other hand, BMI may be underestimated in older people and those who have lost muscle.
How Can This Happen?
You can lose muscle if you lead a sedentary lifestyle, follow extreme diets, or do not consume enough protein. If your weight stays the same but your body is losing muscle, this means that your body fat percentage is higher than your BMI indicates.
When Does This Happen?
People often lose muscle as they get older and become less active. Seniors can often appear slim and score a healthy BMI. But, they may be carrying more fat mass than is healthy for their height.
To find out how much body fat you have, try our body fat calculator to see if you fall into the healthy range.