According to the Centers for Disease Control and Prevention¹, Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. A high BMI can be an indicator of high body fatness. BMI can be used to screen for weight categories that may lead to health problems but it is not diagnostic of the body fatness or health of an individual.

BMI is used as a screening tool to indicate whether a person is underweight, overweight, obese or a healthy weight for their height. If a person's BMI is out of the healthy BMI range, their health risks may increase significantly.