Body mass index, or BMI, is a system of classing people into degrees of wellness based on weight, separating people into underweight, average weight, overweight, and obese. This is solely a ratio of weight to height based on gender, expressed as a number. The number is put into one of the aforementioned categories based on age. Though this number reflects total weight versus height, it does not reflect muscle and fat composition. Because of this, the system is quite skewed.
Because body mass index only considers weight and no other factors, this gives a specific number that applies to a large number of individuals. For example, if a man is 170 pounds at 5 feet 9 inches tall, he is considered overweight. This man could in fact be large and portly, which fits the general definition of overweight; however, this man could appear to be a normal weight but is broad and big boned. A third instance would be a bodybuilder, whose weight is primarily composed of muscle mass, who would have very little body fat. Also, there are weight and build differences among racial groups, which are not taken into account. These examples of different individuals with the same BMI show that, in some instances, body mass index is not ideal for indentifying clinical obesity.
BMI has its limitations but there are no obvious alternatives. One alternative to body mass index is body fat percentage, as it is better for identifying overweight and obesity that could potentially affect someone’s health. Body fat percentages do not take muscle mass, bone density and size, and height into account, which successfully compensates for all of the discrepancies caused by a person’s build and ethnic background. Though body fat percentage is more useful than body mass index, Body fat percentage is also subject to testing error, takes longer to complete the test and can only be done where the testing equipment is available. BMI is readily accessible to anyone, which makes it useful in quickly identifying weight issues. Though BMI could use some improvement, for now it is the best choice for indentifying weight issues.