Beemer (dr_tectonic) wrote,


Ha! I knew it!

It is 9 am, and I have already been at work for an hour and a half, because today is the company health fair and I had a blood draw scheduled at 7:45. Oy vey. They had to stick me twice because I have uncooperative veins; now I know just to go straight for the expert phlebotomist.

Anyway, among the other health screenings, they have the nifty electrical inductance scales that calculate your bodyfat percentage. And now I finally have proof of something I have suspected all along: BMI (Body Mass Index) is a complete lie. (For me, anyway).

I weighed in at 232 pounds, fully dressed. I'm 5'10.5". Thus, my BMI is about 33 1/3. Even if we subtract off 7 pounds of clothes (my scale at home says I'm 225, naked) and round up to 71 inches tall, it's still 31.5. 30 is the cutoff for "obese". To have a BMI of 25, at the upper limit of the "normal weight" category, someone who's 5'10.5" is supposed to weigh between 175 and 180 pounds. (HA!)

BUT! The scale also measured my bodyfat at 27.7%. The attendant said she thought that was even probably several percent high (normal error is +/-3-5%) because I'd been fasting for 12 hours for the blood draw and I was likely a little dehydrated, so let's call it 25%. If I weigh 232 pounds and 25% of it is fat, that means that there are 58 pounds of fat in my body. If I lost ALL of them, I would weigh 174 pounds. So at 0% bodyfat, I would have a BMI of 25, just past the upper limit of "normal"! In other words, it's not physically possible for me to have a "normal" BMI -- not unless I lose a limb or something!

Still, I am kinda fat. How much should I really weigh? Well, if I dropped down to about 200 and the loss was all fat, I'd go from 58 pounds of bodyfat to 26 pounds of bodyfat. 26 out of 200 is 13% bodyfat, which is smack in the middle of the "healthy" range. 200. That seems like a totally reasonable number to me. So I think that will be my fitness goal. (Even dropping down to 215 would get me down below 20% bodyfat and into the "healthy" range.) Of course, the BMI for 5'11" and 200 pounds is about 28 -- in the middle of the "overweight" category.

If 14% bodyfat is the mean of the "healthy" range (for my age), and my weight at 14% bodyfat is 202 pounds, then the BMI for my "ideal" weight at 5'10.5" is 29.0. The mean BMI of the "normal range" is 21.75, which means that, assuming those mid-range numbers ought to line up, BMI is off by more than 7 points for my body frame. So really, my current BMI isn't 33 -- it's more like 26: a little bit overweight, not seriously obese.

I fucking KNEW it. Goddam population statistics.
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