March 11, 2013

BMI - Useful or Useless?



Happy Monday, UFG'ers! 
As I go through this journey with my doctor - there's one measurement that keeps coming up - BMI.  BMI stand for Body Mass Index and it's considered the standard to finding the amount of fat that makes up a persons body.   It's usually found by dividing your weight in pounds by your height in inches.  A healthy weight is a BMI of 18.5-24.9; overweight is 25-29.9; and obese is 30 or higher.

I hate this number.  Hate it.  I started doing some research on what BMI really means, and if it's really accurate.  Here's what I found:



Image via HowStuffWorks.com
According to NPR:
"The person who dreamed up the BMI said explicitly that it could not and should not be used to indicate the level of fatness in an individual.
The BMI was introduced in the early 19th century by a Belgian named Lambert Adolphe Jacques Quetelet. He was a mathematician, not a physician. He produced the formula to give a quick and easy way to measure the degree of obesity of the general population to assist the government in allocating resources. In other words, it is a 200-year-old hack."
Hmm.... sounds pretty shady to me.

I also read that recently, professors at Oxford University have found the BMI measurement to be inaccurate.   Says Professor Nick Trefethen:
“BMI divides the weight by too large a number for short people and too small a number for tall people.”
He added: “So short people are misled into thinking that they are thinner than they are, and tall people are misled into thinking they are fatter."
Interesting!

Here's the facts:  BMI doesn't take into account the difference between lean body mass and fat mass.  I'm not exactly muscular - so let's be honest about the fact that my BMI is pretty much truly fat mass.  However, The Mailman is heavy on the muscle.   His BMI is 25.7.  This, my friends, is considered overweight.  Anyone who's seen The Mailman lately can clearly tell that, if anything, he needs to STOP losing weight!  That's all the proof I need.

My doctor has proven herself to be wonderful.  I went through 4 before I found her, after all!  However, should she be basing so much of my program off BMI?  Maybe not.  I go by how I feel and how my clothes fit.  To me, that's far healthier than going by some seemingly arbitrary mathematical calculation that seems to have very little basis in modern science.

What are your thoughts on BMI? Do you calculate yours? Do you think it's useful, or useless?

2 comments:

  1. This is why I hate the way we measure "weight". Your weight on the scale and your BMI don't take into account how much muscle you have!! For example, I have DROPPED 1 dress size and GAINED 6 pounds. No joke. And, the scales that say they measure body fat don't work (I have one and according to mine I am obese...yeah, not so much.) I wish they would invent an easy, more effective way to measure BF%.

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    1. Very true, Claire. I hate that my doctor measures my health by BMI. With all the advancements we've make in the health sciences, it seems to me that BMI should be rendered archaic by now!

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