Why BMI (Body Mass Index) is Not the Best Option

human_compositionMany of us have heard about body mass index (BMI) and know that it uses height and weight in a formula (that was developed more than 150 years ago) and gives you an idea of where you are regarding your current body weight (i.e. ideal, overweight, obese etc.). BMI is a calculation that takes into account your height and overall weight but does not factor in body fat or more importantly lean muscle tissue. It seems this formula may work for some but if you’re small in stature, older or athletic, the calculation will be inaccurate. This is why most athletes like football players are considered overweight or even obese when their stats are entered into the following BMI calculation:

BMI = Body weight (lbs.) / Height(2) (inches) x 703

If lean muscle and body fat are not calculated into the equation then there is NO WAY it can be accurate, especially for individuals who carry more muscle.

According to many government agencies like the CDC a healthy weight for someone in terms of BMI is about 18.5 to 24.9 – this means if you’re over 25 your over weight. If your BMI happens to be >30 your considered obese. We need to start factoring in height, weight and lean muscle level into this profile and in turn get a more accurate reading.

Maybe we should just use the bathroom scale? The issue with this is that it does not give an accurate picture either it just gives you a number. It’s the ratio of that number (muscle:fat) that you need to determine and track over time and your scale will not differentiate the ratio of muscle and fat. Maybe you can start to use a waist-to-hip ratio (waist/hip measurement) and a %body fat score as part of your own personal health index.  The bottom line is you need to start paying more attention to ratio of muscle to fat that your carrying on that body of yours. There are many ways to determine %body fat (Skinfolds, BIA, TOBEC, DEXA, Hydrostatic weighing, etc.) If you’re unable to use any of these methods then take a simple measurement around your waist. This does not determine overall body fat but it can tell you a great deal. Men should not exceed 40 inches and women 35 inches in regard to a waist measurement.

At the Koko FitClubs around the country we have our members take a FitCheck reading that takes a snap shot of their body composition. It takes into consideration their height, weight, sex and age and offers two important metrics – their current lean muscle level and eBMI (“enhanced” body mass index).

It all comes down to the simple fact that it’s not about one single number – a number like BMI alone or what your bathroom scale tells you should not define who you are. Start paying more attention to the amount of muscle tissue your body is carrying, your strength level or maybe the size of your waist or hips…you’ll be much better off as you age!

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6 Comments

  • Susan says:

    The info here is really beneficial about using numbers with a grain of salt. That being said, the grammatical errors reduce the credibility of the author. Food for thought…

  • Jeff says:

    I tested my eBMI today at a KoKo Fit Club and scored 27.7. FWIW I’m 47 years old, 6′ 4″ tall, and approximately 260 lbs. Lean muscle = 189.6 lbs. Ideally, where should my eBMI be? Low 20’s?

  • wkshank says:

    Interestingly, since starting the Koko program two months ago (with very little change to my diet, which is already healthy), my BMI has actually INCREASED a little (from 31 to 31.2), and the reading of my muscle weight increased only slightly. However, my Q score went up 12 and my total strength gain went up 29%. (I am 51 years old and have a Q score of 55). I have no idea what to make of these numbers. My scale weight at home has hardly changed at all (though I will say I think I look less flabby maybe). I’m having a hard time getting any motivation from any of the numbers, and am more motivated by the fact that I’m able to do increasing weights and harder cardios. Wish there were some way to focus ONLY on real achievement of ability, rather than body numbers… all bodies respond differently to fitness programs. Apparently mine gains weight no matter what I do…

    • michael wood says:

      There is your strength gain, improvements on your aerobic capacity, increased bone strength and feeling better and stronger in all activities outside of a gym

  • Casey Gardner says:

    What is the equation for this eBMI number? I’m familiar with the BMI, but I’ve never heard of eBMI before.

    • michael wood says:

      This is something that we use exclusive to our Koko Fitclubs (http://kokofitclub.com) – Traditional BMI uses height and overall weight but does not factor in lean muscle tissue – the eBMI or “enhanced” body mass index) – looks at height, weight and lean muscle. For me my BMI is 26 but my eBMI is 18.9

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