Body Mass Index is not a test or diagnostic for a particular condition. An abnormal BMI can, however, be a risk factor for other conditions including heart disease. If your BMI is not normal, you should consult your physician about other steps to take to improve your overall health. Your physician may recommend changes to your diet, increased exercise, and better nutrition. Keep in mind that BMI does not measure body fat. It is entirely possible that a bodybuilder could have the same BMI as an obese person. This is because BMI is calculated only by height and weight and doesn’t take other factors into consideration.