Hi. We’ve never met, but I know exactly how much you should weigh.
I don’t need to know your sex, age, your activity level, your family history, your diet or whether or not you have "big bones". Just tell me your height. That’s all the info I need.
Welcome to the Friday morning Body Mass Index edition of WHEE!
WHEE (Weight, Health, Eating and Exercise) is a community support diary for Kossacks who are currently or planning to start losing, gaining or maintaining their weight through diet and exercise or fitness. Any supportive comments, suggestions or positive distractions are appreciated. If you are working on your weight or fitness, please -- join us! You can also click the WHEE tag to view all diary posts.
Let me start by saying that when it comes to understanding your ideal weight, sometimes Body Mass Index (BMI) gets a bad wrap.
Sure, it’s not as fun as underwater weighing. As ticklish as caliper anthropometry. As new as dual energy x-ray absorptiometry. As cool as near infrared interactance. Or as expensive as total body electrical conductivity.
But it’s quick, cheap and simple. And when it comes to living a healthy life, there’s something to say for that. But like most tools, knowing how to use it can make a world of difference.So let me share what I know...
What is BMI?
BMI is a numerical computation. Your weight (lbs) times 703 divided by your height (in) squared. For me that’s 194 x 703 ÷ 68 squared, or 29.5.
No one actually does any math, however, they simply use nice color-coded charts like this one. http://howmuchshouldiweighformyheigh...
The World Health Organization has published the following guidelines:
Underweight: Less than 18.4
Normal: 18.5 to 24.9
Overweight: 25 to 30
Obese: Over 30
I started out this year with a BMI over 35. I will be "normal" once I get down to 164 lbs.
What doctor invented this?
Surprisingly (or not), this was not a medical discovery. The actual computation goes back to the early 1800s. The original term for this measurement was the Quetelet Index, after its inventor Lambert Adolphe Jacques Quetelet, a Belgian mathematician. In addition to his work in geometry, probability, physics and astronomy, Quetelet may be best known for his work in statistics—especially social statistics.
Quetelet was the first to use the normal curve (i.e. a bell curve) and he is credited with coming up with the concept of "the average man" – the central value about which measurements of a human trait are grouped. (I am told that in some of Quetelet’s later work, "average man" is presented as an ideal type, as if nature were shooting at the "average man" as a target and deviations from this target were errors. Guess I am an error.)
While the Quetelet Index is merely a footnote in his biography, this numerical calculation came into vogue in 1972 based on a paper written by Ancel Keys. Keys made his name earlier linking cholesterol and diets to heart disease, and when he proposed that the QI was the best way to quickly assess fatness, people listened.
BMI and me.
Four years ago, I went to a local doctor for my first physical in years. His first words to me were "you are 70 pounds overweight." And to prove it, he showed me the chart. He never mentioned BMI or math or numerical calculations – he didn’t have to. He pointed to the chart and it said I was obese. Who could argue with a chart?
My first memory of the term BMI is from earlier this year when I joined Weight Watchers. When it came time to calculate my "target" weight they had the same chart. At least they explained what Body Mass Index was.
And when I received a quote for life insurance last year that was way more than what my agent promised, I suspect that my BMI of 35+ had something to do with it. But they didn’t even show me a chart.
The problems with BMI.
Our own Edward Spurlock made a comment last month that motivated me to learn more about BMI:
It's nuts that a group like WW, with all their resources, set goals for people based only on weight and height. I hope they're using skinfold calipers now to determine fat % in order to determine what someone should weigh. BMI was designed as a tool for measuring populations - it shouldn't be used as the final word for any individual's weight! And the same goes for weight goals based solely on weight and height - that's a rough estimate at best.
Wiki echoes Edwards comments, noting "BMI has become controversial because many people, including physicians, have come to rely on its apparent numerical authority for medical diagnosis, but that was never the BMI's purpose; it is meant to be used as a simple means of classifying sedentary (physically inactive) individuals with an average body composition."
Obviously, Body Mass Index does not take into consideration your frame size, how much of your weight is muscle or fat, or your level of activity. Because it was developed with the "average man" in mind, it doesn’t work as well with people who fall outside the norm, including athletes, children, the elderly and, well, just about anyone who doesn’t fit the "prototype" standards.
A good place to start – and sometimes a good place to end.
The simplicity of BMI certainly gives it high marks for me. All you need to know is your height, and just about everyone knows that. And for me, hearing the words "you are not overweight, you are obese" certainly struck a nerve and motivated me into action.
If it doesn’t work for you--you can rest assured that it wasn’t designed with you in mind.
Personally, the objectiveness of math appeals to me, especially where I am now in my journey toward living a healthier life. Having lost 35 pounds this year, I keep hearing from people "you look great"... "you’ve lost enough"... "don’t lose anymore"... "losing 30 more pounds would be crazy". Fortunately, I need only take a peek at Quetelet’s chart to realize I still have a few more miles to go.
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Scheduled WHEE diaries:
October 30
Fri AM – in progress
Fri PM sychoticI
October 31 -- BOO
Sat AM - ???
Sat PM - Edward Spurlock (Kessler, Ch. 19)
November 1
Sun AM - kismet -- the calorie value of everyday tasks
Sun PM - Chico David RN
November 2
Mon AM - NC Dem- Muscle of the Month-Deltoids
Mon PM- Cusoon
November 3
Tues AM - ???
Tues PM Clio2 (Kessler, Ch. 20)
November 4
Weds AM - ???
Weds PM - Edward Spurlock
November 5
Thrs AM - ???
Thrs PM - ???
November 6
Fri AM - ???
Fri PM - ???