Body mass index (BMI) is a measurement of body fat based on height and weight that applies to adult men and women.
Generally, if you're at a healthy weight, your body mass index should fall between 18.5 and 24.9, notes the National Heart, Lung and Blood Institute. If your BMI is below 18.5, you could be underweight or high chances of being malnourished. On the other hand, a BMI greater than 25.0 is categorized as already suffering from obesity, while a score above 30 is considered morbid obese.
A body mass index in the low range signals that you could be malnourished. May be your body isn't properly absorbing nutrients or maybe you're just not getting enough calories to support your activity level. Conversely, having a BMI on the higher end alerts your physician that your risks of heart disease, diabetes and certain cancers are higher than someone with a normal BMI. Your doctor might set you up with a registered dietitian, who can help you get your weight back on track and reduce your risk of developing health problems. However if your BMI comes in a normal range you are advised to maintain it by following proper exercise with balanced diet.
While BMI is a preliminary stage to evaluate your health, it isn't the only way to determine if you are healthy. For example, it doesn't account for gender, and women tend to have more body fat than men. So as a woman, even if your body mass index is in the normal range, you could still have a high percentage of body fat. The calculation also doesn't account for muscle mass. Muscle weighs more than fat, so if you lift weights and have toned muscles, your BMI could be high even if you're not overweight. Because of these flaws, your doctor also might do some lab tests to evaluate your blood cholesterol levels. In addition, he might measure your waist. A wider than average waist is another indicator for obesity and the risk of related diseases.