Body mass index (BMI) is a standardized way of determining a person's fat levels by comparing their height and weight.The Body Mass Index (BMI) is a standardized way of determining a person’s fat levels by comparing their height and weight. It is commonly thought to measure the percentage of body fat, however, this is not the case.

The index was created in the mid 1800’s by Adolphe Quetelet and was originally designed for measuring the correct amount of medicine to give a person. In today’s terms, it is used to create a chart that a person can see if they are underweight, normal, overweight or obese in comparison to an average person of their height and weight.

The categories that the BMI uses are applied to all and do not factor in anything other than height and weight. While it is useful for highlighting potential areas of concern for a person, it is rarely used as anything other than this as it simply doesn’t provide enough information or feedback about a person’s general health. Those considered under or overweight may become subject to further tests to ascertain if there are any health risks either physiological or psychological.

While the World Health Organization now standardizes the use of BMI charts, there are multiple variations around the world as people of different cultures will measure differently according to their diet and lifestyle.

Major applications of the Body Mass Index are gathering statistical information across a large set of people due to the speed of calculating it. In a same way this information can be transferred to medical providers and insurance companies as a way of determining a person’s risk relative to their peers. Also, medical insurance companies will use BMI as part of their underwriting process.

Clinical practice uses it as a long-term health monitoring tool, and, as discussed earlier, will use it to highlight potential areas of concern. If a person was to become bulimic or anorexic their BMI should hopefully highlight this with the chances of catching and diagnosing these conditions earlier. While medical and clinical staff would not solely rely on it, it can and is used as a leading indicator for certain conditions.

The main downfall of the index is that it does not factor in anything but height and weight. Gender, age and a person’s muscle mass can all severely affect the results and sometimes produce alarming high or low results despite there being no actual cause for concern. Elderly people with low bone density and body builders are two examples where their BMI may appear alarming despite them being perfectly healthy. Another common criticism is that the index does not give useful information with regards to health other than a person’s weight.