Wednesday, May 25, 2011

My Beef with BMI

I was reading an article yesterday about overweight America that was talking about the issues that Americans face and the poor food choices that we are surrounded with.  It was a really good article until I got to the section that explained how to tell if you, or someone you love, is overweight.  They suggested using the BMI calculation, or Body Mass Index calculation, to tell if you are overweight.  And, as you can tell by the title of this post, I have some issues with that.  But first, I should probably explain what BMI is and how you calculate BMI.

BMI, as I said earlier, stands for Body Mass Index and is a standard way of coming up with a number that tells you if you are underweight, overweight, obese, or at your ideal weight.  BMI takes two factors into account; height and weight.  What happens is that your take your weight (in pounds) and divide it by your height (in inches) squared then multiply that number by 703.  Here's the standard rundown for BMI for a Male and female adult:

Male and Female Adult
0 - 18.5:  Underweight
18.5 - 24.9:  Normal
25 - 30:  Overweight
> 30:  Obese

If you're interested in your own BMI you can go to to see where you come out instead of doing the calculation on your own.

But why do I have a beef with BMI?

One reason. It's far too generic.  Taking into account only the two factors of height and weight is borderline irresponsible.  For example, I had a classmate in chiropractic school who was "ripped" for lack of a better term.  And since muscle weighs quite a bit, he was a little heavier, but by no means unhealthy or overweight.  In fact, he was probably one of the healthiest in our class.  However, according to the BMI calculation, he was almost obese!

If you also don't take into account what your gender is, you're making a big mistake.  Science tells us that women are supposed to have more fat in their bodies than men.  The reason is that women go through much more stress than men in everyday life.  Constant hormonal changes due to menstrual cycles needs slightly more fat stores and it's vital to have more fat stores for pregnancy. 

So what's a better way to tell if you are overweight or in your ideal range?

One slightly better method is called the Waist-to-Hip Ratio.  It is slightly better able to take into account body shape and distribution of weight, which are much better indicators of health.  Click here to calculate your Waist-to-Hip Ratio.

However, possibly the best calculation is to determine your percent of body fat.  Now to get a very good estimation of your percent, it can take quite a few tests and money.  Therefore, it's not the most feasible method.

But, probably the best way to determine if you are of a healthy weight, is to look in the mirror and also to examine your lifestyle.  By leading a life that focuses on healthy eating and regular exercise, you will be hard pressed to get into that obese range.

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