Body Mass Index (BMI): An Unreliable Indicator of Obesity
It’s scary to hear reports telling us that we are currently living in an era with the most obesity in our history. In fact, roughly 1 in 4 Canadians 18 years and older are labeled as ‘obese’. But what exactly does this mean?
It’s no secret that the quality of our diet has dramatically dropped in the last 30-50 years. There has been an exponential growth of refined, processed and fried foods, and a decrease in the consumption of fresh, local, whole food. So it’s no surprise that we are becoming the most overweight generation to ever inhabit the planet. This is one fact I can’t deny.
Unfortunately, the problem we face with obesity has created issues which may now even be impacting those who are not overweight.
The Body Mass Index is the single most common method of measurement used to determine whether a person is overweight. Medical professionals will tell you that a healthy individual should fall between the BMI values of 18.5 and 24.9 kg/m2. According to Health Canada, your BMI is classified as follows:
|15 to 18.49||Underweight|
|18.5 to 25||Ideal|
|25.01 to 30||Overweight|
|30.01 to 40||Obese|
But have you ever stopped to think about how these values are calculated and how it was developed? Believe it or not, this system was created in the 19th century by a mathematician named Lambert Quetelet. And what’s more interesting is that Quetelet specifically noted that the BMI is not an accurate method for determining the ‘fatness’ of an individual and should not be used for this reason. This makes me wonder, if the man who developed the calculations says it should not be used, then why have we accepted BMI as a reliable indicator?
This question lead me to think about BMI in a bit more depth. People come in all different shapes, sizes and structures. And what about the fact that muscle weighs more than fat? This would mean that most athletes and active people would be considered overweight even if they have very little body fat. Here’s a few examples of some well-known people who, according to the Body Mass Index, are overweight. I think you would have a hard time convincing my wife that Brad Pitt is overweight:
|Tom Brady||6’4||225 lbs||27|
|Kobe Bryant||6’6||200 lbs||25|
|George Clooney||5’11||211 lbs||29|
|Tom Cruise||5’7||201 lbs||31|
|Denzel Washington||6’0||199 lbs||27|
|Will Smith||6’2||210 lbs||27|
|Keanu Reeves||6’1||223 lbs||29|
|Brad Pitt||6’0³||203 lbs||28|
|Lebron James||6’8||240 lbs||26|
|Johnny Depp||5’7||190 lbs||27|
|The Rock (Dwayne Johnson)||6’5||275 lbs||33|
So before you run to the gym and have a personal trainer or doctor tell you that you need to lose weight because your BMI is too high, I encourage you to do your research. Keep in mind that everyone is different and there is no perfect system that can encompass all variations of body sizes. This is one of the reasons why I believe the BMI is not reliable.
I would like to leave you with a final thought to consider. We have now started labeling our children with ‘overweight’ and ‘obese’ labels according to their BMI, even if the child is completely healthy. If BMI is not reliable for adults, why would we even consider applying these principles to our children? When I see happy, active kids running around and playing, I can’t help but wonder what good could possibly come of telling these children that they are overweight according to their BMI? You tell me. Do I think childhood obesity is a growing concern? Absolutely. However, I think our methods for determining their level of health still has much room for improvement.