an estimate of total body fat.This number, which is central to determining whether an individual is clinically defined as obese, parallels fatness but is not a direct measure of body fat.Interpretation of BMI numbers is based on weight status groupings, such as underweight, healthy weight, overweight, and obese, that are adjusted for age and sex.The BMI is defined as weight in kilograms divided by the square of the height in meters: weight height2 = BMI.