Q: What is BMI or the Body Mass Index?
A: The Body Mass Index is an equation developed by a Belgian astronomer and Mathematician Adolphe Quetelet in 1850, which is used to determine a person’s level of good health or conversely, obesity. BMI is calculated by taking a person’s body mass and dividing by the square of their height.
Q: Is my BMI all I need to know about my health?
A: No, definitely not! BMI has been a widely accepted indicator of health for over a century; however, recent studies definitively show us that the BMI scale of measurement has become an outdated measure of health. I personally don’t believe it should have been instituted at all.
Q: Why is the BMI system a flawed indicator of health?
A: The BMI measurement is an insufficient indicator of a person’s health because it doesn’t accurately depict the three different measurements associated with weight: muscle mass, bone mass, and fat mass.
BMI uses only weight and height measurements, and is based on averages over history that are generally accepted to be at least satisfactory to other methods of measurement.
The issue with the BMI measurement is that if a person of ‘healthy’ BMI were to lose 10lbs of muscle, and simultaneously gain 10lbs of fat, they would still be considered perfectly healthy, as their BMI doesn’t change. Alternatively, if someone gains 10lbs of muscle, but their fat mass stays the same (resulting in a lower body fat percentage), they will get kicked into a higher BMI category which is then interpreted as being less healthy.
This type of measurement to determine health just doesn’t make sense!
Body composition measurements are a much better indicator of health. These measurements actually pinpoint the percentages of fat, and muscle mass that an individual carries around with them every day.
Q: What are the ramifications of using BMI to measure health?
A: Using BMI to measure health fosters a fitness culture that prioritizes achieving a lower number on the scale, and undervalues strength training, or building and retaining muscle mass.
Theoretically, a person that is of average height and weight but carries around 50% body fat would still be classified as a perfectly healthy person under the BMI measurement scale, when from a compositional standpoint this person is obese. We live in a society with an ever-growing obese population, yet if more accurate testing devices such as Bod Pod’s or DEXA scans were being utilized to measure body composition, those numbers would likely be even higher.
Strength training is one of the most effective ways to improve overall body composition, yet prominent fitness trends of steady state cardio are practiced in far greater numbers than resistance training.
Studies consistently show that those with higher levels of lean tissue age better. People who retain or gain muscle as they age tend to not only live longer, but also have fewer heart attacks, less significant falling events, and better blood pressure measurement than those who succumb to the effects of sarcopenia.
Q: What do you advise that I do for my health instead of focusing on my BMI?
A: I recommend you locate a facility in your area that utilizes proper technology to accurately test people’s body composition. Hydrostatic weighing, DEXA scans, Bod Pod’s (such as the one at our MedX facility in Toronto) and some versions of bioelectrical impedance are all very good options.
- Blair Wilson