Well, I figured this BMI stuff would be a bit of a bore to read, but it turns out I didn't know nearly as much as I thought I knew about Body Mass Index.
First off, as the (sadly) necessary disclaimer, I gotta say I'm no doctor (but I play one on TV...), nor am I a nutritionist, a guru, a nurse, a dietician, a horse, a bookie, or anyone else that might possibly be considered an authority on Body Mass Index. I only checked out two sources, one of which was the lovely Wikipedia article I printed off, and the other being Steve's textbook on human physiology. So, it's just me, a schmoe, reading about this stuff, and trying to break it down to you (as I best understand it). Ok, now that's out of the way....
Body Mass Index was invented between 1830 and 1850 by Adolphe Quetelet, a Belgian polymath (say what?) who was working on "social physics." It is really meant to study the proportion of weight and height at the population level, rather than at the individual level. The actual term Body Mass Index was coined in 1972 by a gentleman named Ancel Keys, who explicitly stated that it was inappropriate for individual diagnosis (I'll explain why in just a moment). It was used for individuals, though, because it was so simple, didn't require fancy schmancy medical equipment, and could even be a tentative starting point for a diagnosis of things like starvation or anorexia nervosa. In the main, it is currently used to determine weight problems in a population, usually whether the population is underweight, overweight, or obese.
The proper formula for BMI is the weight (in kg) divided by the square of the height (in meters). If I knew a little bit more about computers, I would write up the formula for you and paste it up here, but you'll have to bear with me. If you want to figure out your BMI and you live in America, it is your weight (in pounds) multiplied by 703, and you divide that number by your height (in inches) squared.
My BMI is currently at 30.9. I cheated and went to a website to figure it out. I cannot do math, sorry. According to the current guidelines, I am considered to be obese (bummer). A BMI of 18.5 to 25 indicates optimal weight, a BMI lower than 18.5 suggests the person is underweight, while a BMI above 25 indicates being overweight. A BMI of 30 or greater indicates obesity, with over 40 being morbidly obese. A BMI below 17.5 may indicate the person has anorexia nervosa, and a BMI of less than 14.9 indicates starvation.
The US National Health and Nutrition Survey of 1994 said that about 59% of American men and 49% of American women have BMIs over 25. 2% of men and 4% of women were morbidly obese. Then, in 2007, came another survey that said that 63% of Americans are overweight, with 26% being in the obese catagory (go team, go!). So, I guess it's becoming patriotic to be heavy, eh?
Here's where (I think) it gets interesting. BMI can be a quick diagnosis that is not always correct. For instance, with athletes, muscle is denser than fat, and they can come out with a BMI number that is overweight or even obese, although these people are in excellent shape (you think Dwayne Johnson aka "The Rock" has a low BMI?). Also, in children and the elderly, there are considerations that need to be made regarding bone density, loss of height due to aging, different body shapes, and on and on. There are many different body types, as we all know, and the BMI doesn't take this into account...ectomorph, endomorph, pear-shaped, hourglass...you still get the same formula. There are some differences on the guidelines for optimal weight BMIs for countries in Asia, but other than that, it's pretty much a cookie cutter formula, as far as I can tell.
An interesting thing I read as well was the bit about American medical insurance companies. According to Wikipedia, most private health insurance providers use a particular high BMI as a cut-off and then raise insurance rates or deny insurance to higher-risk patients (nice.). This would reduce the cost of insurance coverage to others subscribers in the "normal" BMI range. Some will phase in surcharges as the BMI goes up, additional penalities, etc., up to a maximum BMI where, after that, the individual will be denied coverage regardless of price. This doesn't necessarily include group insurance policies. So, this cookie cutter formula can affect millions of people who are struggling with weight issues, and can condemn them to higher medical insurance rates, or even a complete lack of medical insurance.
So a BMI is not really always the best way to gauge weight loss. I think it can be used as a tool, but I wouldn't hang your hopes on it, or bet the farm. I don't know about you, but it always seems that everything is about BMI right now--why don't "they" talk about it's intended usage, on populations of people, rather than the individual? I suppose because it's such a simple formula. I think I would also get a better sense of my emerging fitness with a tape measure and even (maybe) the scale, but perhaps just a pair of pants that are in a size I want to be. What do you think is the best way to measure healthy weight?
So that is my first assignment, out of the way. Don't grade me, guys! It has been eons since I've been in school, so I hope the information wasn't too jumbled. If you want to read what I read, just go to http://www.wikipedia.org/ and type Body Mass Index into the search engine, and away you go.
You know what I want to tell you about next week? I found an interesting article (again on wikipedia) on female body shapes. Now that's a topic I think might be fun.
My day went fairly ok, otherwise. Andrew didn't get enough sleep last night, so it was screaming tantrums all morning at school, with periods of Evil Mommy In Public phased in. There's nothing like losing your...mind....in public that makes it great to be a parent of a small child. Especially when parents are coming in and out from dropping off and picking up their kids, and can see my son falling out, and me about to ship him overnight to my mother's house. What? Like you never had the urge...
Food went well, and I worked out my upper body this morning with weights. I went and got on the scale today at the Y, and while I had my shoes on and stuff, it looks like I may have lost four pounds! Yay! That's four packages of butter from the grocery store (ew). Seems a lot to me when I think of it that way. I plan to do a proper weigh in (whatever that means) every two weeks, and to re-measure my bits every two weeks as well.
My goal for tomorrow is to actually get up with my alarm clock and go running at 6:30am, instead of feebly pounding the snooze button and running later in the day. Bill Phillips (the author of Body-for-LIFE) says that your metabolism is boosted for the whole day if you work out in the morning, and frankly, I could use all the help I can get! Wish me luck! I'm going to do it tomorrow! See you then!