Wednesday, March 26, 2008

We need a BMI Chart for (former) fat people.

Someone needs to come up with a BMI chart for people that used to be fat.

I've often wondered how in the world I could possibly hit even the max end of the BMI chart for my height. 159 is a BMI of 25 for a 5'7" male, and 25 is "overweight". So I'd need to be 158. Wow. How's that ever going to happen?

So I decided to check my body fat. I checked 3 times with 3 methods, and came up with these numbers:

You have 20.4% body fat.

You have 39.4 Pounds of fat and 153.6 Pounds of lean (muscle, bone, body water). (weight = 193)

You have 21.6% body fat.

You have 41 Pounds of fat and 149 Pounds of lean (muscle, bone, body water). (weight = 190)

You have 22.6% body fat.

You have 43.2 Pounds of fat and 147.8 Pounds of lean (muscle, bone, body water). (weight 191)

We'll take the middle estimate of 21.6% with 149 pounds of lean. That would leave me, at 158 pounds, 9 pounds of fat. We'll round up and call that 5.7% body fat.

But Dan, you may be asking yourself, what's the problem with that?

Allow me to tell you how body fat percentages break down for white males:

Average American 22%
Healthy normal 15%
Top Athletes 3-12%

That's right - to hit "healthy normal" I'd need to weight 175, with about 26 pounds of body fat.

Even if I hit 0% body fat, that still puts me at a BMI of 23.3, way at the high end of "normal".

I've heard several theories, but the one I like best, that makes the most sense to me, is that when you're as fat as I was, your muscles have to develop a greater density just to support all that extra mass. We're talking structural musculature here, so don't get all excited that under all that flab lurks a weight lifter's body. Since we, as fat and former fat people, are carrying this extra muscle, we weigh more and it throws us off the (BMI) chart.

For me, this all works out OK - my goal is to bring my body fat down into the 5-7% range anyway, and see how that looks. But for someone that just wants to lose the weight and get healthy? Looking at this chart could be very demoralizing. So don't look. Use the scale to chart your progress, and when you start getting down closer to the size you want to be, start using body fat to choose a weight goal if you need to. Or choose a clothing size you want to be. If you are, or have been, more than 100 pounds over weight, realize this chart may not apply to you.

Next up: I have muscles now I've never known about!

No comments: