Hey BMI – I Wish You Weren’t a Liar!

 In Blog

The BMI, while a good measurement, isn’t the end-all, be-all standard when it comes to your health and fitness. If you’re serious about getting in tip-top shape, there are other things to consider.

“Hey BMI – I Wish You Weren’t a Liar!” was actually an idea that popped in my head watching Anchorman: The Legend of Ron Burgundy. See, I’m not the biggest fan of the measurement, so when I saw the scene where Ron tells his co-worker that he wishes she wasn’t a liar, I immediately jumped off the couch and went to work on this post. There was a creative spark and I would like to relate it to an apple falling on Isaac Newton’s head. Okay, maybe that’s pushing it just a tad. See, clients come to me with concerns about their BMI, and while not completely unfounded, I think we need to dig a little deeper to understand our health (or lack there of).

First and foremost, perhaps calling the BMI a liar is a tad harsh. It’s not actually being dishonest. Let’s say it skims the surface of telling you how fit you are.

The BMI measurement refers to the Body Mass Index, where your weight (in kilograms) is simply divided by your height (in meters squared). This standard is used to classify obesity; a “healthy” BMI should range between 18.5 to 24.9 kg/m2 (1). If you’re below 18.5 you need to gain weight. Coming in above 24.9 and you need to lean out.

But not so fat. Anecdotal evidence points to the fact that:

  1. There are people with a BMI over 25 who happen to be very healthy (and not overweight)
  2. Those with a healthy BMI actually have severe health issues, with high bodyfat being one of them. But how could that be if the BMI says they’re healthy? I’ll explain.

Let’s clarify topic #1. Using an example, perhaps the webmaster here at UEFP (who also happens to be my lovely wife) is five feet, four inches and has a BMI of 26.5. This 26.5 classifies her as overweight, but her bodyfat percentage is under 15%. That’s pretty trim for a female client. As you can see in this picture, we’re dealing with a fit woman. You’d be hard pressed to call her overweight.

Muscle mass plays a part too. Bodybuilders and many athletes will have high BMI’s but very low levels of bodyfat. So what gives?

The BMI doesn’t give us the full picture. While insurance companies might give my wife crap for being “overweight”, other indicators tell us she’s pretty healthy. So what might those measurements be?

  1. Bodyfat percentage
  2. Waist measurement

The BMI will be accurate for many individuals. But those exceptions – and there are quite a few- would be better served using bodyfat percentage and their waist measurement. The issue here is that of the distribution of bodyfat.  A sport scientist such as myself will use a caliper to measure your skinfolds. This is a technique used to pinch the skin in several areas of your body. It’s a solid method because not only will it track your fat loss, but the pinches can also give us an idea of any hormonal problems (2).

Someone may have a low BMI but at the same time have also problems with testosterone, cortisol, and insulin (to name a few). We also know that carrying high amounts of bodyfat around the midsection spells trouble for your heart. This is where the waist measurement comes in. One of the popular terms used today is that of skinny-fat: people who have an acceptable body weight but have very little muscle mass and accumulate their bodyfat around their waistline. So their arms and legs appear almost skinny, but the torso tells a different story. This explains issue #2 from above. Our client has a low BMI but a ton of visceral fat surrounding their mid-section and digestive organs. That’s a bad recipe for longevity.

To bring it full circle, I was being a little mean when I called the BMI a liar. But if you want to reach your pinnacle in health and fitness, you’ll have to look at the full picture. If you can’t get your bodyfat percentage measured by a qualified trainer, wrapping a tape measure around your waist (right where your belly button is) is a great start. Males want to be below 36 inches while females should shoot for anything below 32. Once you do that, you can tell with if you’re in shape or not and I’ll know if you’re lying J.

1. Colberg, Sherri R. “Nutritional Status and Chronic Diseases.” ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription. 6th ed. Baltimore; Lippincott, Williams, and Wilkins. 2010; pp 115

2. Berardi, John. Andrews, Ryan. The Essentials of Sport and Exercise Nutrition 2nd ed. Precision Nutrition. 2013.pp 317

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