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02 April 2008 @ 08:43 pm
It's no longer enough to be the "right" weight  
Doctors have now invented normal-weight obesity.

Normal weight obesity: An emerging risk factor for heart and metabolic problems
Submitted by BJS on Thu, 2008-03-27 13:14. Topic: * bioscience and medicine



More than half of American adults considered to have normal body weight in America have high body fat percentages -- greater than 20 percent for men and 30 percent for women -- as well as heart and metabolic disturbances, new Mayo Clinic research shows. The finding conflicts with the widely held belief that maintaining a normal weight automatically guards against disorders such as high levels of circulating blood fats and a tendency to develop metabolic syndrome, which often leads to type 2 diabetes.

The researchers defined “normal weight” by body mass index (BMI). They found that people with normal BMI who had the highest percentage of body fat were also those who had metabolic disturbances linked to heart disease. The researchers use the phrase “normal weight obesity” to describe this new type of patient at risk for metabolism problems and risk factors for heart disease, but who rates as “normal” on standard weight charts. They defined normal weight obesity as a condition of having a normal BMI with high body fat percentage. The Mayo team will present its study results at the American College of Cardiology’s Annual Scientific Session next week in Chicago.

“Using the term ‘normal weight obesity’ is really a way of being more precise about the changing conceptualization of obesity, because the real definition of obesity is excess body fat,” says Francisco Lopez-Jimenez, M.D., a cardiologist on the Mayo research team. “Our study demonstrates that even people with normal weight may have excessive body fat, and that these people are at risk for metabolic abnormalities that lead to diabetes and, eventually, to heart disease.”

Significance of the Mayo Clinic Study

Heart disease remains the major cause of death and disability in westernized countries. Researchers around the world are striving to refine the relationship of body composition to heart health as a means of:

* Designing more effective risk assessment tools

* Improving public health programs for reducing risk

* Designing new and better clinical rehabilitation programs for heart patients

While a focus on maintaining “a healthy weight” has long been a centerpiece of these efforts, Mayo’s new study suggests the focus may need to shift. Instead of tracking weight and BMI only, public health measures to prevent heart disease might benefit more from measuring the belly or by assessing percentage of body fat as more reliable risk factors of heart disease. Mayo studies in 2006 and 2007 suggested this criterion by demonstrating the inability of BMI to discriminate between body fat and lean muscle. “Combined, the data from our earlier work and the current study suggest it’s time for a new measure of body fat as a risk factor of heart disease,” says Dr. Lopez-Jimenez.

About the Study

The researchers studied 2,127 adults, equally divided between men and women, who had normal weight (BMI between 18.5 and 24.9 units). The participants’ body composition was assessed, and their risk factors for metabolic and heart disease were collected by the U.S. government in its Third National Health and Nutrition Examination Survey http://www.cdc.gov/nchs/products/elec_prods/subject/nhanes3.htm [1].

From this data, researchers found that normal weight obesity appears to be highly prevalent, affecting more than half of patients with a normal weight as defined by the BMI. After controlling for age, sex and race, normal weight obesity subjects had significantly higher rates of several alterations in blood chemistry that can negatively affect heart and metabolism health. These markers of disregulation include:

* Altered blood lipid profile, such as cholesterol

* High leptin, a hormone found in fat and other tissues and is involved in appetite regulation

* Higher rates of metabolic syndrome
Source URL:
http://www.scienceblog.com/cms/normal-weight-obesity-emerging-risk-factor-heart-and-metabolic-problems-15754.html

Links:
[1] http://www.cdc.gov/nchs/products/elec_prods/subject/nhanes3.htm

 
 
 
Bladerunnerbldrnrpdx on April 3rd, 2008 01:34 am (UTC)
Good ghods, so even if I weren't too fat (which I am, by any medical standards), even if I were the right size, I'd still be fat. I knew there was no way to win!
Submarine Bellssubmarine_bells on April 3rd, 2008 01:37 am (UTC)
Well, folk have been saying for ages that the BMI measure is Stoopid. Unfortunate phrasing choices aside ("normal weight obesity"? Puh-leeze.) maybe this is the first nail in the coffin for the BMI-as-a-proxy-for-good-health type of thinking?

(OK, I'm an optimist. Sue me.)
Fat Fred the Otter and Skippy: iotterfatfred on April 3rd, 2008 02:15 am (UTC)
To be human is not to be "right".
Next life, I'm coming back as an otter.
redneckgaijinredneckgaijin on April 3rd, 2008 03:00 am (UTC)
So, in other words, if your BMI checks out as normal (i. e. "lathe-thin, skeletal, prone to blowing away in slight breezes"), you're STILL FAT?

Jesus H. & R. Christ.
Shadow/Brookekengr on April 3rd, 2008 04:19 am (UTC)
No. BMI (the way they are using it there) is merely a number on a table that cross-indexes your height against your weight.

Some day I will unearth my high school yearbook in storage and have pictures that show the sort of skin & bones I was at several pounds *over* what my "ideal weight" is according to those stupid charts.

Folks with "light bones" or very little muscle tissue but lots of fat will meet the "normal" height/weight criteria. But the actual perccentage of body fat will be way over the top.
Beckyladysprite on April 3rd, 2008 12:14 pm (UTC)
Folks with "light bones" or very little muscle tissue but lots of fat will meet the "normal" height/weight criteria. But the actual perccentage of body fat will be way over the top.

Not necessarily. I'm near the low end of acceptable BMI, I have normal bone structure (neither "big-boned" nor light), and I'm stronger and more muscular than most of my friends and coworkers. I just happen to be lucky enough to have the type of build that fits this niche - but having a normal BMI is not a guarantee of having a high percentage of body fat.

Personally, I agree that BMI is mostly malarkey; I just hope that the study leads researchers to the reasonable conclusion that it's the body fat ratio, rather than the height ratio, that matters....
starcat_jewel: disgustedstarcat_jewel on April 3rd, 2008 04:52 am (UTC)
Boy, they are just DESPERATE to make sure those dollars keep rollin' in!
Spark_in_darknesssparkindarkness on April 3rd, 2008 11:46 am (UTC)
Well, BMI is dumb and it's about time they realised that. Someone with a lot of muscle mass may actually be considered overweight, while someone who has all the muscle tone of wet celery and lots of flab may actually be considered normal weight at the moment. To say nothing of natural frame etc etc. The whole mess just seems to think there's some kind of "standard" human shape that anyone can reach

I don't know if it's all overly simpliefied (by being generic for everyone) or just overly complex (when any decent doctor can tell you on a one-on-one basis whether you are of an unhealthy body weight without any damn silly charts)
fatcook: Angry-Annoyedfatcook on April 3rd, 2008 02:21 pm (UTC)
Ohh, of the love of....
I'm so glad I've finally learned to ignore what the "experts" say.
Genetypographer on April 3rd, 2008 03:19 pm (UTC)
To be fair/accurate, they have been saying for years that the body fat percentage was the important factor. The various height/weight charts and the BMI measures have often been the result of demands from health boards or other governmental agencies to come up with some standard chart that they can just publish and tell people to use.

Certainly I can recall literature read on the subjects of obesity and heart health over two decades ago indicating that a condition like this was possible.

So it would be more correct to say that a study has verified the existence of this condition, and the search for a name has begun.
gh4acws on April 3rd, 2008 07:21 pm (UTC)
yeah!
since BMI uses mass and the square of height I am not sure how one could expect it to work - except in the very limited sense that people with extreme numbers should CHECK if they are to skinny or obese. ( I too have met a fanatic bodybuilder whose BMI must have been worse than mine, but whose muscle to fat ratio certainly was healthier than mine.[ not opening the can of fishing supplies on weather he was/is healthier than me].

One would expect a different index that uses mass divided by the cube of length to be more precise : however that seems to change very slowly over the range. I conclude that humans do not scale well.
Tiirztiirz on April 4th, 2008 06:41 am (UTC)
I went to the doctor for tests, as I'm working out and trying to eat better, and I was surpised that though I really need to loose a gignormous amount of weight, I don't have high blood pressure, heart problems, blood fat, ect. =Steve's= on high blood pressure meds, not me! And he's not fat at all. Doctor says anything else will go away when I drop a bit, no need to stress, but I have really, really heavy bones, never even broken one and I sink like a stone in water.