Posted on 09 October, 2017

​ BMI debunked – why Measurements need more attention

By Sam Todd in Exercise, Fitness, Health, Lifestyle, Nutrition ​  BMI debunked – why Measurements need more attention

[Image source: Daily Burn]

You may have heard of a little measurement called the BMI, or the Body Mass Index.  The BMI measurement was first derived in the early to mid-1800s by Adolphe Quetelet, a Belgian astronomer, mathematician, statistician and sociologist.

Speaking of lifestyles, if you are eating healthily, moving regularly and keeping a healthy mindset, then analysing BMI and basing your worth on it isn’t going to be very helpful!

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So far in modern history, the BMI has been seen as the only number that “if not fully satisfactory, [the BMI] is at least as good as any other relative weight index as an indicator of relative obesity” (Ancel Keys, Journal of Chronic Diseases, 1972).  Well, I’m here today to put things into perspective when it comes to BMI.

The BMI is calculated by the body mass (kg) divided by the body height (m) squared, and is expressed in units of kg/m².The results table looks a little like this:

​  BMI debunked – why Measurements need more attention

[Image source: www.doctorandrewwu.com]

So, basically, the taller you are, the heavier you are “allowed” to weigh.  Now that we’ve got that out of the way, let’s think about a footballer.  A footballer in your local league may be 178cm tall and weigh 101kg.  We know that that 101kg is mostly a result of muscle mass as the player eats well (except for the odd beer on the weekend), and trains hard.  But the BMI doesn’t.  This football hero’s BMI of 31.88kg/m² says that he is not only overweight, but obese.

Now let’s think about the local grocer.  He is a small man, only 165cm tall, and weighs in at 67kg.  Everyone knows he likes to have a lot of takeout and he is always sneaking lollies behind the counter.  To top off his unhealthy lifestyle, he is a smoker.  The BMI doesn’t know any of this, and gives the grocer a number of 24.6 kg/m², putting him in the healthy weight range.

Who is more likely to be unhealthy in this picture?  Who is most likely to have health problems later in life?  Who would you rather be 10, 20 years down the track?

Let’s take the same two people and take their body measurements.  Better yet, let’s use the Waist-to-Hip Ratio (WHR).  The WHR indicates risk of obesity.  The WHR is calculated by dividing the waist measurement by the hip measurement. The WHR results table looks a little like this:

​  BMI debunked – why Measurements need more attention

[Image source: Free Clipart Website]

Now, let’s go back to our first two examples and get their measurements.  The local footballer has a waist of 80cm and a hip of 95cm.His WHR is 0.84, which puts him in the excellent category, meaning he is at very low risk of obesity.  Moving onto our local grocer.He has a waist of 85cm and a hip of 80cm.  His WHR is 1.06, which puts him in the at risk category, meaning he is at very high risk of obesity.  These results reflect a lot better on our two men’s lifestyles.

Speaking of lifestyles, if you are eating healthily, moving regularly and keeping a healthy mindset, then analysing BMI and basing your worth on it isn’t going to be very helpful!  You didn’t put in all that hard work into living a healthy lifestyle to be told off by a number!  Take body measurements if you must, but please remember that there is a lot to be said for ignoring the numbers, and focusing on how you feel in yourself, your mind and your body.

Does your BMI give an accurate representation of you?

About Sam Todd

About Sam Todd

Sam is a mother of two, a personal trainer and a positive body image enthusiast.  Her hobbies include running, mucking about in the gym and watching her Melbourne Demons play.

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