How good is BMI as an indicator of body fatness?

The correlation between the BMI and body fatness is fairly strong, but even if 2 people have the same BMI, their level of body fatness may differ.

In general,

• At the same BMI, women tend to have more body fat than men.
• At the same BMI, Blacks have less body fat than do Whites, and Asians have more body fat than do Whites
• At the same BMI, older people, on average, tend to have more body fat than younger adults.
• At the same BMI, athletes have less body fat than do non-athletes.

The accuracy of BMI as an indicator of body fatness also appears to be higher in persons with higher levels of BMI and body fatness. While, a person with a very high BMI (e.g., 35 kg/m) is very likely to have high body fat, a relatively high BMI can be the results of either high body fat or high lean body mass (muscle and bone). A trained healthcare provider should perform appropriate health assessments in order to evaluate an individual's health status and risks.