Interesting story today on MSN about the limitations of using BMI, or body mass index, as a measure of body fat.
When I checked my BMI a couple weeks ago it said I was 25, which is the very beginning of the overweight category. It pushed me to join up for the mayors' challenge to try and lose 10 pounds and get healthier. All of which is positive.
After reading the article on MSN, I played around with the BMI calculator. I would have to drop three pounds to 147 to be in the "normal" category.
But clearly, as the article points out, there are limitations to using BMI. I would still be considered "normal" at 113 pounds! There's no way I'd be "normal" at that weight. I'd be dying. I think I weighed more than that in high school, for god's sake.
It doesn't change my motivation to get fit, but I don't think I'm going out on a limb by saying that BMI might not be gospel.
Anybody have anything to add on this debate?
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7 comments:
At 172 lbs., it says I need to drop about 7 to be at a "normal" 25 BMI. But, uh, to lose 56 lbs and still be "normal"? I don't even think undergoing gastric bypass could get me down that low. I seem to remember weighing that in 8th grade.
This makes me feel better about the whole BMI thing, but I'm not looking forward to wrapping a tape measurer around my beer gut. Not sure if I even have a tape measurer.
I recently calculated my BMI after some creeping weight gain, and was shocked to find that my BMI was 25, and thus over the border into the Land of Overweight. It had an impact on me, as I've started trying to exercise more and eat less. I'm also trying to make better food choices.
If one uses the BMI as a guidepost or benchmark in that way, then maybe it's a useful tool for the average person. College football players probably know from their trainers exactly what their weight and body fat should be, so I doubt athletes of that caliber will be alarmed or confused.
BMI as a calculation of healthy weight range is pretty inaccurate.
For example let's take a women of 5'4 and 140 pounds. According to the BMI chart ideal weight is between 108 - 132. For one that is quite a range. If that women was 108 it would mean she would have very little lean muscle mass. Lean muscle mass is the most important aspect of body composition.
So a woman could be at 140lbs but be 18% body fat. That to me is ideal in a health factor. It should also be noted that professional bodybuilders are considered obese by most BMI calculations because they are heavy in actual weight, but it doesn't take into account there lean body mass.
My point being is the scale does not always measure the ideal. These charts do not always measure ideal.
My methods of testing healthy body composition goes in this order of importance.
-Body Fat
-Waist to Hip ratio (good for determining disease warning signs)
-General Measurements
-Good Ole Fashion mirror
-Scale
BMI chart, isn't even on my list.
Just catching up on the blog!
A little note about the BMI...BMI was originally created as a measure of weight independent of height in order to study adiposity in large populations. This is important b/c it allows us researchers to gather an easily assessed measurement of adiposity and study its relationship with disease risk(cardiovascular disease, cancer, etc)......however there are issues with applying it to an individual....one of which was mentioned by leigh - muscle is heavier than fat, so one could have a relatively high weight in relation to their height, but have very little fat on their body....the best example that was ever given to me was that Arnold Schwarzenegger would be considered obese?????
So, the other measures mentioned by Leigh are very important in assessing overall weight health for an individual.
Having said all of that - the BMI is still a fairly good way of tracking progress (moving from overweight to normal category) and figuring out the "general" range you should be in....it works for most people except for hard core weight lifters.
Also - I will apologize for getting all researchy on ya, but weighing yourself on a fairly regular basis has been found to be one of the most important behaviors used among successful weight losers. It is a concrete way of self monitoring and being accountable for your actions.
So don't be too afraid of the scale!!! Have you weighed yourself lately, Amy?
oops, I read the article after I wrote my message...oh, well....you will certainly understand the uses and limitations of BMI now!
What the heck is adiposity?
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