BMI Calculations

Why BMI is NOT a good indicator for overall health

 

The problem with BMI calculations is that it makes an assumption of someone’s health based solely on their height and weight. Although BMI calculation may be accurate for someone that lives a sedentary lifestyle, Bodybuilders are the ones that really get punished the most by the results.  Lets take a look at the BMI formula before we go into why it is not a good indicator for overall health.

You can either use pounds or the metric system to calculate your BMI.  The formula for each system is below:

Using pounds to calculate BMI

*Note:  weight in pounds and *height in inches

Using the Metric system to calculate BMI

*Note:  weight in kilograms and height in meters or centimeters

Using the BMI chart below you can get a good understanding of what the calculations mean.  The list below is broken down into four categories: underweight, normal, overweight and obese.

Why the BMI index does not work

Let’s use an example where two people who are 5’ 8” and weigh 220 pounds. The first person in our example has a body fat percentage of 33% while the second one is a bodybuilder with a body fat percentage of 7%. The first person in our example, we will call him John, is carrying a lean body weight around 174 pounds thus carrying about 72 pounds of fat. Our bodybuilder in the example, who will refer to as Matt, has a lean body weight around 204 pounds carrying about 16 pounds of fat. Now let’s look at the BMI calculations for both of our examples.

Since both of our guys are the same height and weight there is only one formula to use to calculate their BMI. Even though both of them have drastically different body fat percentages they both receive a BMI score of 33.4. Now a BMI over 30 is considered obese and here is where the problem lies. John is definitely obese and the BMI score gives a pretty accurate result for his health. However, Matt is by far not obese and his BMI score is grossly wrong in its calculations.

As you can see a BMI calculation cannot be used for everyone.  BMI is just not a good indicator for someone’s health and should be avoided when making any health assumptions. Although the BMI calculations are fairly accurate for someone who lives a sedentary lifestyle, the calculations really should be avoided by anyone with a muscular physique. The best recommendation for getting a good indicator of your health is to invest in something that actually tracks your body fat percentage. Although this is not the “end all be all” indicator for overall health it will give you a good idea of where you are at. There are a variety of different calipers, body fat calculators and analyzers available that will help you get a good understanding on your estimated body fat percentage. You can learn more about the different body fat monitors available at www.one4fitness.com.