The Body Mass Index (BMI) has many limitations. Even though it correlates with the amount of body fat, it is not a very good indicator for evaluating the health affects of being overweight or obese as the current study below indicates. It is not applicable to athletes who have highly developed muscles which contributes a high degree of lean body mass. In these people, their BMI may be high but their disease risks may be low. It is also not accurate in the elderly population who may have lost muscle mass referred to as sarcopenia.
It may be more important to access the location of body fat stores. There are two major body fat locations: subcutaneous fat which is located under the skin. This type does not appear to increase health risks. The second type of adipose tissue is visceral fat which is located around the organs in the abdomen. Generally, fat in the hips and thighs is primarily subcutaneous and abdominal fat is visceral. An increase in visceral fat is associated with a higher risk of heart disease, high blood cholesterol, high blood pressure, stroke, diabetes and breast cancer.
Many health experts promote the use of the waist circumference which can roughly estimate the risk of visceral fat and should be used with the BMI. Visceral fat storage is more common in white men than in women. However, after menopause, visceral fat increases in women. For men in the greater or equal to a 25 BMI range, a waist circumference greater than 40 inches is associated with an increased disease risk; for women in that BMI range, a waist circumference of greater than 35 inches increases risk. If a person is under five feet in height or has a BMI greater than 35, these cutoffs are not helpful in predicting health risks.