Back in February of 2017 on another blog platform that I ran, I published an article looking BMI as an accurate weight measurement tool. I thought that by now, most wellness professionals in the industry had concluded that the BMI tool cannot be used as an accurate tool to measure body weight, if at all. Well that’s what I thought, until last week when I read the article “What Is Your Body Mass Index” published by Texas Health (Presbyterian Hospital Flower Mound) https://www.texashealthflowermound.com/weight-loss-center/body-mass-index/
In this article, they state that “the higher the BMI, the higher the obesity level and probability of life threatening conditions such as heart disease, type 2 diabetes, and many types of cancer”. I was particularly disappointed with this statement because this is simply not true.
What Exactly Is BMI?
Medical and fitness professionals use the BMI to tell them how much fat you carry. The acronym stands for Body Mass Index. It describes the number you get from dividing the height by the weight of an individual. It is supposed to tell the tester if the subject is underweight, of normal weight, or obese. That is, it tells you if you are carrying a lot of fat on you, just some normal fat, or no fat at all. Sometimes the BMI is referred to as the Quetelet Index. This is because it was coined by a Belgian mathematician by the name Adolphe Quetelet. It is important to note that this index was not originally coined to be used to measure individual body weight to height relationship. The goal was to find a way to easily classify the physically active group in a very large population. So it was initially designed to determine obesity in large populations and not individuals.
BMI = weight in kg/height in meters squared x 703
BMI = weight in pounds/height in inches squared x 703
Here is the what the index looks like:
Less than 18.5 kg/meter squared = UNDERWEIGHT
18.5 to 25kg/meter squared= NORMAL WEIGHT
25 to 30kg/meter squared = OVERWEIGHT
30kg/meter squared and over = OBESE
Did you calculate your BMI? Did your result surprise you?
In my personal opinion, BMI is simply an interesting tool. One may use BMI as one of measurements for general health/fitness assessment, but not as the only measurement. This is because the test focuses only on weight and height and neglects gender, age or muscle density. We all know muscle weighs more than fat meaning one pound of fat takes up more space than one pound of muscle. So why would a seasoned body builder and another physically unfit man with same exact height and weight have the same BMI? That is hardly accurate? This is why the BMI scale would classify people that seem very fit as being overweight and even obese. A very lean person that is taller than a person with more way more body fat will be classified according to this BMI scale as overweight. The BMI should not be the only tool used to assess your personal fitness or obesity. You should also use your waistline measurement to accompany your BMI. The BMI is a good screening tool but a bad a diagnostic tool.