Weight Loss Support - NPR bit called "Top Ten Reasons Why the BMI is Bogus"




elle w 19
07-05-2009, 11:35 PM
Wanted to share this link...kind of makes you think about giving the BMI too much importance. While it's useful and fun, this article shows how it can be flawed.

http://www.npr.org/templates/story/story.php?storyId=106268439&sc=fb&cc=fp


kiramira
07-05-2009, 11:42 PM
:rofl:

Is NPR SERIOUS??? Thanks for the laugh!

BMI is simply a guideline to indicate where there may be a weight issue. Other than for most elite athletes, the numbers are indeed fairly accurate as an indication of whether or not someone should be further investigated to determine if they are carrying excess weight. It is simply an indicator of whether further investigation should be done. My DH is 6 ft and 182 lbs and very fit, but is high on the BMI chart. His physician sees that he does not have a weight issue but used the BMI as a springboard for other tests. Which shows that BMI is a guideline, not a "diagnosis" of fatness.

OF COURSE other methods MAY have to be applied, but it seems pretty obvious to me that ANYONE who is 5 foot 5 and 400 lbs is morbidly obese rather than a misunderstood elite athlete! And ANYONE who is 5 foot 7 and 86 pounds needs to eat.

HONESTLY!

:lol:

Kira

ps. I wonder if the author has been in a SoCal suburban mall lately -- he can't seriously believe that the majority of Americans are fit and healthy!!! Oh, and I LOVED the theory that BMI should be discarded so as not to embarrass the United States. STILL laughing over THAT one...

mandalinn82
07-05-2009, 11:57 PM
Obviously, there are extremes, as Kira mentioned, but in either of those cases, you wouldn't NEED a scale/calculation to determine if the person was at a healthy weight. It would be apparent that the individual was drastically overweight or underweight, no matter what number on the BMI scale.

The issue comes in classifying people who are closer to the "underweight", "normal", and "overweight" ranges. There is nothing that indicates that if I have a BMI of 25.1, for example, and I lose 2 lbs to get into "normal", my health will improve. The BMI was originally formulated to look at populations, not individuals (as the NPR article mentions). Too many health professionals and individuals are taking those numbers as gospel, trying to hit normal ranges even if their bodies are telling them something different is what is right. Someone who is built with a very slim build and has a metabolism like a hummingbird may be MEANT to have a BMI that, for most people, is "underweight"...just as someone with a very thick, muscular build who is really active and has built a lot of muscle may be meant to have a BMI that for most people is "overweight". Applied to individuals, it just doesn't take enough into consideration.

I also find the BMI to be really, really arbitrary, especially since research is anything but solid on what BMIs are really associated with low health risks (though 23 - 28 seems to come up a lot, insurance tables created earlier in the century have lower numbers, and there's definitely not agreement on what range is the best in terms of life expectancy). If "normal" doesn't mean "most likely to live longest", what does it mean? And if we don't KNOW what BMIs are associated with the longest lifespans, why are we recommending that particular range to -every- patient?

In my ideal world, doctors would advise patients on a healthy, calorie-controlled diet and lots of exercise, and then disregard (or at least de-emphasize) the scale. If you are doing those two things, most likely you'll lose weight and settle into a healthy weight for you, whether you are a more "average" build and that falls into "normal", or if you're more of an outlier on build, moderately above or below it. Either way, focusing more on the behaviors and less on the scale would prevent patients from being discouraged by WEIGHT and help them focus on improving health, and isn't that what it's all about?


mandalinn82
07-06-2009, 12:13 AM
Oh, and I LOVED the theory that BMI should be discarded so as not to embarrass the United States. STILL laughing over THAT one...

It's not like he was saying that he wanted BMI discarded because the numbers in the US are high and embarrassing. He was trying to say (I think, at least) that using the BMI to make health recommendations, when it does have so many flaws, is embarrassing for a nation with the scientific and technological knowledge we have (in other words, we should know better).

joyra
07-06-2009, 12:33 AM
I'm really turned off by some of the language of this article... "hack" "embarrassment"... it sounds like an attack and makes me feel defensive of the BMI. When I read the article, I almost interpreted it as saying "Oh your BMI indicates you're overweight--ignore it, it can't be trusted."

I guess my only argument is what other obesity indicator is so easily accessible? It would be nice if there were a more scientific indicator of weight that factored in more data such as waist and sex but... I don't think there is.

mandalinn82
07-06-2009, 12:43 AM
Waist size seems pretty clearly correlated with health risk. It is, in particularly, great at identifying "normal" weight people at higher risk of death and disease due to higher levels of abdominal fat.

http://www.theepochtimes.com/news/8-7-4/72954.html

http://docnews.diabetesjournals.org/content/2/2/6.1.full

http://www.nature.com/ijo/journal/v25/n8/full/0801640a.html

mamaspank
07-06-2009, 01:04 AM
I love NPR! I can't believe I missed this show. I appreciate hearing other points of view, but can't help but agree with NPR.

jendiet
07-06-2009, 09:58 AM
hah! Thepoochtimes--love it. I think although BMI may be exaggerated in it's usefulness the caliper method is awesome. I hate my pooch and that's what I concentrate on most my spare tire around my middle. That's where my high BMI is.

I also love that the article links high waist circumference with hyperinsulenemia---insulin resistance.

kiramira
07-06-2009, 10:24 AM
Like I said, BMI is an indicator when you get into the grey areas of over/normal/overweight. It isn't the be-all and end-all.

But here are some facts to consider:

The average weight of an American woman has risen by 20 lbs since 1977.
http://www.reuters.com/article/lifestyleMolt/idUSL0778048620070807

The average weight of an American man has risen from 166 lbs in 1960 to 191 lbs in 2002.
http://usgovinfo.about.com/od/healthcare/a/tallbutfat.htm

Americans are getting, well, fatter, cause it sure as HECK isn't due to an increase in gym memberships and fitness regimes. And the scary part is that articles such as the NPR one is clearly along the lines of NORMALIZING this trend. If everyone is LARGER, then that becomes the NORM. And the scary leap is that if it is the NORM, how can it be UNHEALTHY? And how DARE you call me fat, when I am NORMAL.

And then aLOT of time goes into the reasons WHY Americans are bigger today -- they have more MUSCLE (yeah, right -- like the majority of Americans are taller and FITTER instead of fatter).They are 1 inch TALLER than in 1960 (like that accounts for 20 lbs). The MEASURING GUIDE IS FLAWED. If we change the parameters of the measuring stick, then suddenly, we aren't fat anymore. We are all "normal". And there isn't any weight problem at all!

SO IRRITATING, as there is a move to normalize the not normal! And articles such as this let people rationalize away their weight issue -- it isn't ME, it's the fault of the BMI system. Don't they SEE that I have alot of muscle under this beer belly? Don't they REALIZE that I park my minivan further away from the shopping mall entrance than my friends and I WALK all the way there? Don't they REALIZE that although I am a pear-shape and my bottom measures 52 inches, my waist is only 34 inches, so how can I be THAT overweight?

The BMI system is perfectly valid to show trends, and alert practitioners to potential medical issues on an initial screening. And if it WASN'T seen as valid, it wouldn't be a determining factor when deciding if a patient was eligible for bariatric surgery.

Like ALL tools used in analysis, it isn't perfect. But neither is any other system. Personally, IMHO, it is a pretty good indicator of whether or not a person is packing some extra pounds (the mid-ranges of the BMI charts coincide pretty well with the Met Life Actuary tables). Its usefulness comes in identifying trends, and as a quick screening method used at a hospital and doctor's office that opens other, more time-consuming avenues for assessing weight and weight issues. It DOESN'T indicate if one is healthy at that particular moment in time. But neither does ANY method.

JMHO

Kira

kiramira
07-06-2009, 10:31 AM
OH! And this--
From the article the OP quoted:

[The BMI method is] a 200-year-old numerical hack developed by a mathematician who was not even an expert in what little was known about the human body back then.


The author of the article is a mathematician without any human sciences training, and has no expertise in what is known about the human body today...:lol:

Kira

Lori Bell
07-06-2009, 10:44 AM
Huh? I love the BMI chart...lol Compared to the old height and weight charts of the 70's and 80's I can weigh a good 10 pounds MORE and be considered "normal". Remember the old men/women charts where you would add 2 inch heel for women height and one inch for men? ( Like we wore our shoes to get measured and weighed.... :) Large frame, medium frame, small frame etc. (How did you decide that?) I'm a simple person with a simple mind, and I'm all for a nice round AVERAGE! ;)

Tomato
07-06-2009, 11:52 AM
I guess my only argument is what other obesity indicator is so easily accessible? It would be nice if there were a more scientific indicator of weight that factored in more data such as waist and sex but... I don't think there is.

How about monitoring BF% rather than BMI? It does not factor in waist but it does factor in sex, and also age.

mandalinn82
07-06-2009, 12:07 PM
I do believe that the BMI is a valid measure for looking at weight, particularly weight increase, across populations. Again, my problem is using that number as weight loss gospel, particularly in medical or health settings, when there are measures that are just as easy to get (not much harder to put a tape measure around someone's waist than to throw them onto a scale) but better predict health risks for an individual, as opposed to a group.

Every study that I've seen comparing how waist size and BMI predict cardiovascular risk has found that, once decoupled from waist size, BMI doesn't mean much, and that, once decoupled from BMI, waist size indicates a LOT. It's a lot more sensitive on an individual level to the kind of fat that actually causes health problems (abdominal/visceral fat) than BMI, which just measures the weight of -everything-...bone, muscle, fat...and makes assumptions (that may or may not be right) about what those pounds are coming from.

I'm not arguing (and I don't think the author was arguing) that Americans aren't getting fatter, or that measures like the BMI are useless for watching that trend. My argument (and I'll let the article speak for the author's argument) is that the medical and weight loss communities have let a group trending measure go far beyond its original purpose to become the end-all-be-all for whether one is at a good weight, health-wise, and that measure is insufficient to fill that role. The problem doesn't come with using the BMI for trending...again, that's what it was intended for. It comes when you use the BMI for prescribing behaviors or categorizing a particular individual, without additional information, or when you use it as the only guiding figure to determine what weight you should be.

I'm also saying that when setting weight loss goals, particularly in medical settings with docs advising patients, I'd LOVE to see the focus be on healthy behaviors (and possibly weight size), for a couple of reasons. First, I think a lot of docs "you're overweight" conversation doesn't give nearly enough specifics about HOW to do so...When I was heavier, I got a lot of "You have a BMI of X, you need to lose Y pounds, so you should be working on that". Which is useless, because most people who need to lose weight KNOW that they need to lose weight. Much more useful would have been a conversation that said "You have some extra weight on you, and I'd like to see you eat a calorie-controlled diet of about X calories and exercise 20 minutes a day. Doing that will likely move you toward a healthy weight for your body". Second, I think that going ONLY by the scale (which is all the BMI does) is discouraging for people. Focusing on something more static (healthy behaviors, waist size) will give people a solid target, still, without the daily fluctuations and headaches that are the scale.