DEXA vs BMI

2011-04-01 updated 2011-09-13 • SEND FEEDBACK •
Related: body fat, health, metabolism, training

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One of the measurements the medical profession uses today is the BMI, or body mass index. A putative scientific assessment, BMI is an example of intellectual malpractice when applied to individuals, because it can characterize overweight people as fit, and lean healthy people as overweight.

Analysis of the numbers is done to reach conclusions about general public health (that’s fine), but BMI is all too often applied to individuals by “experts” and health care professionals, who have no training in statistics, and thus have no idea of the fundamental intellenctual blunder of applying a statistical curve to an individual. These dimwits weigh someone with 10 pounds of clothing and shoes and iPhone and wallet and so on in their pockets, then point to a chart. Unbelievably stupid and just friggin intellectually lazy—why do they even bother weighing if done so sloppily?

No one needs BMI to see that a guy with a pot-gut and saddlebags is overweight. And if it’s not obvious, BMI is not the right tool. A mirror is a lot more accurate than BMI for any particular individual.

My BMI

I am more physically fit than 99.99% of the population, and my body fat was 12.6% as of May 2011 (8% in 2012). Yes the charlatans at WHO tell me that I’m borderline overweight at 12.6% (see DEXA scan below). Even as my body fat dropped to 7.9%, the 0th percentile, the WHO has me categorized as not that far away from being “overweight”. Which is idiotic.

A glance in the mirror will tell you a lot more than BMI ever can.

Beware of doctors who apply BMI to you instead of treating you as an individual. BMI is a statistical approach and it is intellectual malpractice to substitute it for individual assessment.

No competent doctor needs BMI to assess your health. But because stupidity has been institutionalized by insurance companies (to justify treatment of obesity), you might run into it, whether the doctor wants to use it or not). And it’s also used for the usual dumb-it-down reasons so that patient can understand one simple number (most people want a pill and a simple number without the harder work of real health and knowledge).

At 12.6%

Here I am in the 2th percentile nearly “overweight”:

Example Dual-energy X-ray absorptiometry or DEXA scan for your author

At 7.9%

Here I am in the 0th percentile for body fat. The table from the jackasses at WHO say I’m not that far off from being overweight. This moronic reasoning is coded into the DEXA scanner software.

Example Dual-energy X-ray absorptiometry or DEXA scan for your author