Thursday, November 02, 2006

BMI Not TMI

A little more on the BMI: The index was “invented” by Belgian man named Adolphe Quetelet, who’s identified as a “polymath.” I’m not exactly certain what a polymath is, but it sure doesn’t sound fun.

During the course of this writing, Lancet medical journal published meta-analytic research (of 40 studies) out of the Mayo Clinic suggesting that those with too-low BMIs were at greater risk for heart disease-related death than those who had BMIs in the normal range. Moreover, those considered “overweight” by classic BMI standards actually had a higher rate of survival (with fewer heart problems) than those in the “normal” BMI range.

Head researcher Francisco Lopez-Jimenez says “Rather than proving that obesity is harmless, our data suggests that alternative methods might be needed to better characterize individuals who truly have excess body fat compared with those in whom BMI is raised because of preserved muscle mass.”

It took the Mayo Clinic until 2006 to come up with this? Our gold standard isn’t so golden, after all.

In another article in the same issue of the Lancet, Maria Grazia Franzosi states, “BMI can definitely be left aside as a clinical and epidemiological measure of cardiovascular risk.” Instead, it seems that waist-to-hip ratios are, for now, the way to go. And Grazia Franzosi’s research suggests that these ratios are good prognostic indicators of cardiovascular health. Still, we seem glued to a number (from pounds to BMI to ratios) that is, at best, a gross estimate of an individual’s unique biology. When it comes down to it, it’s easier to address a number than a person.

8 comments:

PalmTreeChick said...

Ahh, the BMI again. I still think that measuring one's body fat percentage is the most accurate way to determine if I person is or is not overweight.

disordered girl said...

BMI always infuriates me because muscle/bone density plays much more of a factor in the right weight for you than your height does. Everyone is different that way! The only way to measure that, from what I understand, is the underwater test. I need to have that done again! Anyway, BMI numbers always tell me I am borderline obese, which I guess is why they infuriate me!

Anonymous said...

I am borderline overweight according to BMI, and I am 5'6" and a size 8. I run, lift weights, and do yoga.

But, Andy Roddick, Yao Ming and George Bush are also "overweight". So I don't put much stock into it.

Debstar said...

Will we all start saying "Is my waist too big for my hips?" or " Are my hips too big for my waist?"

Definately body fat percentage is the way to go. But what would I know, I'm a middle aged, middle class housewife and they are emminent scientists.

Haley-O said...

I never look at the BMI index anymore. I just don't think that people can be pigeon-holed like that -- even if there is a wide range available. I think -- if you feel good, feel healthy and mobile, you're good to go. :)

drstaceyny said...

ptc--yes, body fat % seems to be a better indicator.

dg--yep!

anon--ditto.

ds--ha!

haley--I think you're criteria much better. : )

Elizabeth McClung said...

I think the BMI is a bit like the DSM IV - once you assume everyone fits in a giant equation then having the people who fall outside that equation ignored is the inevitable outcome.

When I took health we had to memorize body types from Ecto to Endo - none seem to be equated on the BMI.

I ate 200-400 calories a day for 9 months, bruised when sitting down, only facial bones and joints could be seen and was eventually consented for hospitalization against my will - I never dropped lower than 21 on the BMI (a "healthy lifestyle").

Elizabeth McClung said...

Sorry - I recalculated and it never went below 19