Most of us have heard of the BMI scale to measure whether we are underweight, healthy weight, overweight, or obese. BMI stands for Body Mass Index and is calculated using the metric system. The formula is a person’s weight in kilograms divided by height in meters, squared (BMI=kg/m2). The result of this formula allegedly determines whether one is under/normal/over weight or obese according to the categories listed below:
Underweight = <18.5
Normal weight = 18.5–24.9
Overweight = 25–29.9
Obesity = BMI of 30 or greater
I have used BMI many, many times in the past 10 years of being a personal trainer and was instructed to do so in my formal education. However, I started to notice certain situations (that were not very uncommon) when BMI seemed to be painting a false impression of one’s weight/health status. You see, BMI is ONLY a ratio of height and weight and that is absolutely all. The article entitled “Top Ten Reasons Why The BMI is Bogus” by Keith Devlin clearly describes how the BMI can be deceiving, discriminating, and plain false. Here are a few of his main points:
Delvin’s Point: It makes no allowance for the relative proportions of bone, muscle and fat in the body. But bone is denser than muscle and twice as dense as fat, so a person with strong bones, good muscle tone and low fat will have a high BMI. Thus, athletes and fit, health-conscious movie stars who work out a lot tend to find themselves classified as overweight or even obese.
My two cents: For example, one of my trainers who is muscular, lean and fit has a BMI of 34.7, so apparently he is OBESE! He is the furthest thing from that I assure you, but on a doctor’s chart, that is what it would say.
Delvin’s Point: Insurance companies sometimes charge higher premiums for people with a high BMI. Among such people are all those fit individuals with good bone and muscle and little fat, who will live long, healthy lives during which they will have to pay those greater premiums.
My two cents: I have heard from a few fit clients that they in fact fell in the higher ranges and therefore have had to pay more for their insurance coverage. So they are actually being penalized for being fit, while others with less muscle (and possibly more fat) would potentially pay less. Ridiculous!
Delvin’s Point: Continued reliance on the BMI means doctors don’t feel the need to use one of the more scientifically sound methods that are available to measure obesity levels. Those alternatives cost a little bit more, but they give far more reliable results.
My two cents: Exactly.
Delvin’s Point: It embarrasses the U.S. It is embarrassing for one of the most scientifically, technologically and medicinally advanced nations in the world to base advice on how to prevent one of the leading causes of poor health and premature death (obesity) on a 200-year-old numerical hack developed by a mathematician who was not even an expert in what little was known about the human body back then.
My two cents: While I agree that the U.S. population has far too many that are overweight/obese, the misleading BMIs would easily skew the statistics even further in that direction…which we do not need of course! I am quite confident that we are known around the world at the “Lazy Nation,” and we do not want the fit and muscular people’s BMIs increase our already poor statistics!
In summary, it isn’t really about what you weigh, but more about what is your weight. Take Arnold Schwarzenegger vs Bill Clinton.
Arnold BMI: 30.5 (obese); Height: 6’2”
Bill BMI: 29.1 (overweight); Height: 6’2”
Obvioulsy, Arnold is not obese and has a much lower body fat than Dear Bill…I don’t want to be the one to tell Terminator that he is paying more in health insurance coverage than the world’s biggest McDonald’s fan!!