Body Mass Index or BMI

  I grew up with a mother who was always watching her weight.  By the time, I hit 13, I understood all the math involved in counting calories so one could loose weight.  Later on, after I graduated from college, I learned calories was no longer the thing.  People now checked their Body Mass Index or BMI.

The formula used to calculate a person's Body Mass Index is their weight in pounds times 704.7  all divided by their height in inches squared.

So if a person weighs 145 lbs and is 5 ft 6 inches tall the formula would look like (145 * 704.7)/66^2 which gives a BMI of 23.46.  Anything between 19 and 24.9 is considered healthy.  One problem with this formula is that it does not measure overall fat or muscle. Its pretty much just a ratio.

I thought it was was something new but the formula has been around since 1830 when it was developed Lambert Adolphe Jacques Quetelet, a Belgian mathematician and scientist.  The formula was created to give an idea if the person weighed a healthy amount.

At the time he developed this formula, there were no calculators, computers, or other such devices so the formula had to be calculated by hand. Some people argue that the formula says you are lighter if you are shorter and heavier if you are taller.  In 2013, a mathematician argued the formula needed refinement.

He recommended the formula now read ( the weight in pounds * 5735)/height in Inches^2.5.  I tried it out and for me, the BMI produced by this formula wasn't that different from the one produced by the original formula.  As stated earlier, the formula does not take into account the difference between fat and muscle.  It is known that muscle is 18 percent denser than fat.

This means that a person who is 6 feet tall, weighs 203 pounds and does not exercise will have a BMI of 27 while a person who is 6 feet tall, weighs 211 pounds and is an Olympic athlete will have a BMI of 28.  Two people in very different shape but with almost the same BMI.

It has been suggested that the Waist to Height ratio is a better indicator of heath than the BMI  because it is more accurate. The idea is that the waist circumference should be no more than half your height.  So if you are 60 inches tall, your waist measurement should be no more than 30 inches.  So if you are 60 inches tall with a waist of 25 inches, you are in good shape.

There is research indicating that over 54 million people has a BMI indicating they are over weight while their waist to height ratio indicates they are within a normal range.  Which is right? Who knows.

I decided to write on BMI and waist to height ratio's because they are both used in the health industry.  Let me know what you think, I'd love to hear.  Have a great day.