Monday, July 24, 2006

BMI Tables

The Body Mass Index (BMI) is a simple measure, based on height and weight, commonly used to determine if someone is overweight. When policy makers and public health officials talk about the obesity crisis in America, they’re usually referring to BMI data, which, when considering the host of variables that should be taken into account when determining the health consequences of weight (i.e., muscle weight), emerge as overly simplistic. In The Diet Myth, writer Paul Campos offers a few examples of "fat" celebrities, according to BMI definitions (over 25 = overweight, over 30 = obese). Coming in as overweight are: Brad Pitt, Michael Jordan, and Mel Gibson. Obese celebrities include: Russell Crowe, George Clooney, and Sammy Sosa.

Campos goes on to say that current BMI definitions are not intended “to apply to people in ‘good shape.’” However, since one of the primary goals of public health initiatives (and the weight-loss industry) is exactly that, for people to be in “good shape,” then why wouldn’t current BMI criteria apply to them?


PalmTreeChick said...

Yeah, the BMI is a little tricky because you can have two people, the exact same height and the same exact weight, which would mean their BMI would be the same. However, on person may be all muscle and the other person all fat, therefore one is healthier than the other, but they both appear to be of the same health on paper.

I think body fat percentage is probably a better way of measuring one's health.

It's like the term "skinny fat person." A person could be very thin, but have a high body fat percentage because they don't have any muscle tone. Where as someone with more muscle will weigh more than a "thin" person, but may in fact actually wear a smaller size, or what not, than the other person because muscle weighs more than fat, but takes up less space.

Did any of that make any sense??

littlem said...

Thank you, Dr. Stacey, for pointing out the enormous cognitive dissonance in the constant touting of the BMI as Holy Grail.

And has anyone who trumpets them as the standard "from which we should never deviate" noticed that those figures were apparently

1) created by an insurance company (MetLife), NOT by doctors

2) sometime in the 50s

3) based only Caucasian men, no women, no other ethnicities, in the sample? Even for the figures of what the women should weigh?

Anonymous said...

Same thing can be said for many health equations. Maximum Heart Rate Equation (220 - your age) is waaaay off and not to be trusted either.

I read a great book (PTC, you'd really enjoy it) last year called "Ultimate Fitness" ALL about fitness myths, and how they came to be. I can't remember the authors name - but she works for the New York Times as a health journalist.

I am a personal trainer, ultra-distance athlete and swim coach currently earning my Masters Degree in Human Performance and Fitness.

Great Blog! I lurk nearly daily now.

PalmTreeChick said...

Yeah, anon. I wear my heartrate monitor everyday when I'm working out and when I run, my HR can be 185 and I don't feel like I'm working too hard. (I'm 28). I teach aerobics. Thanks for the book info.

wading through recovery said...

I thoroughly enjoyed that you used all males for examples in this post.

Keep up the good work!

drstaceyny said...

ptc--yes, that made sense. The trouble is, how many insurance companies are going to pay for underwater weighing? ; )

m--good points (much like other medical indications which are largely andro/Caucasian-centric.

anon--thanks for reading and for the book rec (I'm interested, too). I think the Karvonen formula for max HR is a bit better, since it includes resting heart rate, but I feel the need to caution not to throw this type of info out the window--they're (albeit rough) guidelines for monitoring yourself.

wtr--those were the only examples Campos gave. We all know that a woman who weighs more than she "should" (even b/c of muscle) is quite simply. . . fat. ; )

PalmTreeChick said...

My guess...None! ;) They won't even pay for ed treatment centers. We'll all just jump in a lake to get measured. Ha!

I was actually in my pool the other day thinking about body fat and trying to figure out how I'd be able to measure it in my pool. Obviously, I can't, but my wheels were turning. I thought, hmm, the faster I sink when I blow out all my air, the less body fat I have. Too bad I have nothing to measure it against.

I have had my body fat tested, just not that way. Oh, that's so a post for me because it was such a traumatic experience.

Amazon Alanna said...

My husband is a classic example of this. His BMI is 36...obese. He is a competitve weight lifter and has 7% body fat. Clearly not obese

drstaceyny said...

AA-7%?? Case in point!

Kelly said...

Everyone touts the BMI as being vastly superior to the old school height/weight charts. In reality, I see no difference between the two. I am "obese" based on my BMI, but I am also very muscley. While I definitely need to lose weight, and am working on it, when I have mentioned to friends that I am technically obese, they don't believe me.

According to height/weight charts and BMI, I have been an ideal weight once in my life, after jaw surgery when my mouth was wired shut for 4 1/2 weeks. I looked awful and sickly, and finally stopped getting concerned comments about a year later after I'd gained about 20 pounds. According to BMI, even at that weight (the low end of my goal weight now) I am almost "overweight."