Body mass index BMI
Though it does not actually measure the percentage of body fat, it may be a useful tool to estimate a healthy body weight based on how tall a person is.
Body mass index is defined as the individual’s body weight divided by the square of his or her height.
The BMI formula uses height and weight measurements to calculate a BMI number. This number is then plotted on a chart, which tells a person whether he or she is underweight, average weight, overweight, or obese.
A BMI of 18.5 to 25 may indicate optimal weight; a BMI lower than 18.5 suggests the person is underweight while a number above 25 may indicate the person is overweight; a BMI below 17.5 may indicate the person has anorexia nervosa or a related disorder; a number above 30 suggests the person is obese (over 40, morbidly obese).
An important detail to note is that BMI itself does not diagnose any sort of health risks or problems. It is used purely as a measurement tool and to determine the possibility of risks and problems. Once a health professional has found that your BMI is high, there are other tests and evaluations that are used to determine if you are at risk for or have health problems. A high BMI does not always mean you are unhealthy.