The passage of time adds validity to most things. About 200 years ago a Belgian named Lambert Adolphe Jacques Quetelet produced the formula we have come to call the Body Mass Index (BMI). Professionals in the fitness and medical industry trust this formula because it is a fast way to determine the degree to which one may be obese. Over time, the BMI has become a staple in the industry; therefore, it must be infallible, right? A recent article in the Wall Street Journal added to the credibility of measuring being fit through the BMI. Yet it’s not quite so simple.
The BMI serves a good purpose when there is a need to quickly figure out the degree of obesity for a large population of people, not necessarily to accurately calculate an individual’s obesity level. For example, schools may use the BMI to obtain a general calculation for many students, although not a particularly accurate calculation for each individual student. Outside of this implementation, the BMI is not, in fact, particularly useful.
BMI is defined as the individual’s body weight divided by the square of his or her height. For example, if you are a lean six-foot tall man who weighs 195 lbs, your BMI would be 26. Twenty-six on the BMI scale is considered overweight. Many fit and healthy six-foot tall men weigh in excess of 195 lbs and are by no means overweight. Anything below 19 on the BMI chart is considered underweight, 19-24 is considered normal, 25 to 29 is considered overweight and everything above 30 is considered obese.
The BMI can be misleading. For example, if a very fit athlete or celebrity calculates his/her BMI, there is a good chance that they will be placed in the overweight category. Many athletes and celebrities have bodies ordinary people hope to achieve. So common sense tells us that they should not be considered overweight. There is a reason for these skewed results. Bone is denser than muscle and twice as dense as fat; thus, the person—famous or otherwise—with strong bones, good muscle tone, and low fat will have a high “overweight” BMI.
Even though the BMI is just a number, people place a lot of faith in numbers. But keep in mind that it’s just a number. What really matters is sticking to a proper diet and maintaining a regular exercise routine. Yes, obesity is an epidemic. Yes, we should utilize all that we can to prevent it from spreading over time. But we should be more considerate about blindly trusting a calculation system that is outdated and frequently misused.
George Guerin is a personal trainer whose client list includes some of New York’s best toned bodies. His website is www.pptswellness.com
