June 24, 2009

More Evidence That Overweight is The Healthiest Weight

I have posted in the past about how analyzing the findings of NHANES III (The large, ongoing US national heath study) demonstrated, conclusively, that Overweight is the Healthiest Weight.

Now a second large-scale study confirms this finding. This one analyzed "11,326 adults in Canada over a 12-year period using data from the National Population Health Survey."

You can read a report about the study here:

Reuters: A few extra pounds can add years to your life: study

The actual study is here:

BMI and Mortality: Results From a National Longitudinal Study of Canadian Adults" Heather M. Orpana, et al. Obesity advance online publication, June 18, 2009; doi:10.1038/oby.2009.191

This study is particularly interesting to me because of one significant difference between it and the earlier NHANES III study. The NHANES study only found a health benefit to being overweight in older people. This study found the advantage extending to a much larger age range. The population studied here was age 25 and older.

The most salient finding of this study was that the most unhealthy weight was one that produced a BMI under 18.5. People with that weight were 73% more likely to die than people with a normal BMI.

But get this: People with a BMI of 25-30 were 17% less likely to die than people with a normal weight. Even those classified officially as "obese," people with a BMI of 30-35, had a 5% lower risk of death than normal people.

Only those who were seriously obese, with a BMI was greater than 35, had a greater risk of death than normal, but that risk was only one half the risk the skinnies ran--36% as opposed to 73%.

The researchers who discovered this are falling all over themselves arguing the public should ignore their results and continue to fear fat. Obviously they are influenced by their religious belief that Fat Is Bad.

For example, one of the researchers, David Kaplan, is quoted saying, "Our study only looked at mortality, not at quality of life, and there are many negative health consequences associated with obesity, including high blood pressure, high cholesterol, and diabetes."

Since over 12 years, the overweight and modestly obese people in this large sample were outliving the others, you have to wonder why the researchers didn't do some sub-analyses to see how many of these longer living folk had diabetes, high cholesterol and high blood pressure. Or, more importantly, whether they had been diagnosed with these conditions but had them under control. One almost wonders if these sub-analyses were done but turned up facts so incongruent with their religious belief the researchers dismissed them as impossible.

In any case, this study suggests to me that the current hysteria about obesity needs to be reexamined. The most frequently promoted cure for obesity is weight loss surgery (WLS) a procedure that studies find has a kill rate around 1%--though a kill rate as high as 3% has been reported in some studies. These new statistics suggest very strongly that the argument that these murdered obese people would have died soon anyway, so the high risk of death is justified, simply does not hold water.

A drug that killed that many people could not be sold legally in this country. That
a surgery that risky is being embraced by almost the entire medical community without question shows you just how insane the Fear of Fat has become.

This study also raises some interesting questions about what is killing those skinnies. One reason may be that they may be skinny because they are heavy smokers and drinkers--both addictions can keep weight down and both lead to early deaths.

My own experience over the years has also been that the thin and often vegan people my region are the people most likely to get fatal cancers at young ages. I don't know if that is because the defects in their genes that make them susceptible to cancer also keep them from putting on weight and incline them towards the diets they prefer or what. But you have to wonder now that two major epidemiological studies have shown that thin kills.

As a final note: many of those who contact me are very worried because, while they can take off some weight eating a low carb diet and watching their blood sugars, their weight stalls above the normal range and their doctors continue to assure them that they'd be healthier if they could only lose that last, resistant 20 or 30 lbs.

This study suggests very strongly that their bodies know something their doctors do not and that the weight at which you stall after a serious diet effort that includes blood sugar control may very well be the healthiest weight for you.

8 comments:

Anonymous said...

I have just been reading "Lung function, respiratory symptoms, and the menopausal transition," J ALLERGY CLIN IMMUNOL, JANUARY 2008
It's conclusion is that "Menopause is associated with lower lung function and more respiratory symptoms, especially among lean women." Their lean group had BMI below 23. Having gone to all the trouble of losing weight, and having reached the menopause and developed asthma, I feel really irritated. My BMI is about 21. Even now, I still feel I'd look better a few pounds lower, and it's very hard to shake off the popular images of skinny=healthy & attractive, and accept that actually a bit plump is healthier.

Jenny said...

I just have to keep reminding myself that 1/3 of Dr. Barzilai's centenarians were obese at age 50.

I'm right at the upper border of normal, but only as a result of immense self control, and, let's be honest, vanity.

Our society does put a huge premium on slimness and having a "good figure" and it is very hard to realize that the matronly woman is, traditionally, the one who lives to be the wonderful, welcoming grandmother.

Jim said...

I always enjoy your comments, but I don't always agree. This one of those times.

Quality of life is very important to me, and I am definitely feeling stronger and happier as pounds are falling off on my low carb diet.

I'm more concerned about this:
"while they can take off some weight eating a low carb diet and watching their blood sugars, their weight stalls above the normal range"

So far, I'm doing well. and I hope I don't stall (again).

Nick said...

Jenny, this topic reminded me of your excellent post on Dr. Rudolph Leibel's seminal research on obesity. He made some very important observations that lead me to believe that overweight in itself is not necessarily associated with mortality or poor health. And if 1/3 of Dr. Barzilai's centenarians were obese at 50, how many more were merely overweight?

I am very much still in the learning stages with regard to physiology (motivated by learning I had high FBS and hypoglycemia), but I have come to believe that what our diet consists of is far more important than where our weight setpoint is. As you point out, our organism very much wants to protect us from getting more than 15% away from this set-point. It seems that many of the harmful changes that we experience on the hormonal and cellular level are more likely caused by a reaction to what our bodies have been exposed to, particularly what we eat - perhaps gluten, HFCS, pollutants, excessive amounts of fructose, sucrose and glucose, etc. Could it not be that inflammation is much more highly associated with mortality than weight?

Perhaps sleep efficiency plays into the equation as well. Many obese people have sleep apnea and wreak havoc on the organism's ability to properly remove CO2 from the bloodstream and the ability of cells to protect or repair themselves (including brain function). Who knows how much this might be a cause of problems that are blamed on weight?

Liebel made the following two observations:

"Obese people actually have larger amounts of lean tissue than normal weight individuals do. About 30 percent of the increased weight of an obese person generally is in lean body mass."

"At usual body weight, if you look at energy requirement per unit of lean body mass, lean and obese individuals are not different. That is a very important observation. It is one of the points that indicates that lean and obese people are really not different in terms of their underlying metabolic status when they are at usual body weight."

It may very well be that the increased mortality of people with a very low BMI is due to very low lean muscle mass and the assault of years of the Standard American Diet, including avoiding healthy fats. Over exercise could very well be a contributor as well. Leibel also points out that between the ages of 30-55 the average weight gain is 20 pounds. What he doesn't mention is that many of us lose lean mass as we age. Other studies seem to indicate that over-exercise while dieting can lead to loss of lean muscle tissue along with the fat tissue. The association between weight loss and mortality in the elderly likely has many causes, but losing more and more lean mass and a lack of protein in the diet are likely major contributors to maintaining relatively better health while aging. It seems that maintaining lean muscle mass should be a high priority. I can't help but wonder if one reason so many people begin to experience health issues normally associated with 'overweight' are really a result of the assault of the SAD and losing so much lean muscle as we age.

At 6'1", I much prefer my weight at 187 than when I weighted 195 and have my preferences with regard to what I find attractive. I'm not sure our society is that different to many others with regard to biases about obesity.

By the way, I found that the interview with Liebel was cut off after 8 pages. Were you able to read the whole interview?

pooklaroux said...

Most of the people i know who have died as a result of heart disease or cancer have also been on the slim side, some vegetarian. I found it very telling that a woman I know who confided to me that since she had stopped dieting to fit into size 0 jeans, she hadn't been getting sick with colds and bronchitis as often as she used to. I'm not slim. Even when I was young and not fat, I wasn't a slim girl -- I have apparently always had a high level of lean muscle mass -- thank my genes -- I am not particularly athletic. But anyways, I think I can actually trace my fatness back to being put on prednisone -- and the resulting glucose imbalance. I'm not sure I ever regained a normal glucose tolerance after that. Changing my diet, eliminating grains and lowering all carbs, has stopped my weight from climbing -- but I cannot lose. I can eat just protein and fat for extended periods, and I feel better, but I lose no weight. When I train with weights, I get heavier as my muscles get stronger, and some parts of my body get slimmer, but not all. It is really comforting to think that my larger than average body might not be such a death sentence. Sign me -- "Size 11 shoe"

Anonymous said...

A high BMI reduces your chance of survival and a BMI between 22.5 and 25 is still the best.

The relation between BMI and survival is a complicated by confounding with smoking and thus can be found back only in very large, long lasting studies, because most studies agree that the effect of smoking cannot be compensated for just linearly.

Here is a recent meta analysis of 57 prospective studies in The Lancet.The abstract is free, the article is free if you register :

The Lancet, Volume 373, Issue 9669, Pages 1083 - 1096, 28 March 2009
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(09)60318-4/abstract

Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies.

Editors' note: Around the world, increasing body-mass index (BMI) is a major public concern. Rightly so, according to this international collaborative analysis of almost 1 million people, followed from middle age in 57 prospective studies. A J-shaped mortality curve is observed, with optimal survival at a BMI of 22•5–25 kg/m2. Above this range, mortality from several causes—especially vascular diseases—was increased. Moderate obesity (BMI 30–35) was associated with 3 years’ loss of life. People with extreme obesity (BMI 40–50) lost 10 years of life, equivalent to the years lost by lifetime smoking.

Findings
In both sexes, mortality was lowest at about 22·5—25 kg/m2. Above this range, positive associations were recorded for several specific causes and inverse associations for none, the absolute excess risks for higher BMI and smoking were roughly additive, and each 5 kg/m2 higher BMI was on average associated with about 30% higher overall mortality

Interpretation
Although other anthropometric measures (eg, waist circumference, waist-to-hip ratio) could well add extra information to BMI, and BMI to them, BMI is in itself a strong predictor of overall mortality both above and below the apparent optimum of about 22·5—25 kg/m2. The progressive excess mortality above this range is due mainly to vascular disease and is probably largely causal. At 30—35 kg/m2, median survival is reduced by 2—4 years; at 40—45 kg/m2, it is reduced by 8—10 years (which is comparable with the effects of smoking). The definite excess mortality below 22·5 kg/m2 is due mainly to smoking-related diseases, and is not fully explained.

hth
Gys de Jongh
jongh711@Planet.nl

Jenny said...

Gys,

I'm not convinced by the metastudy because of the GIGO factor. I can't read the full text as Lancet is only free for a few articles as a trial, then you have to pay.

But with the studies included in the metastudy, it is possible you are seeing self-reported weights or other differences in methodology.

The statistical power of the two single studies is very high, and I'd trust them as much as what happens when you glom data together from a series of unrelated studies.

Anonymous said...

"Attractiveness" is so subjective – and not necessarily tied to BMI. For those who haven't seen it, here's an interesting Flickr set of photos of people at a wide range of BMI levels. http://preview.tinyurl.com/2jkzuu
As you can see, "overweight" or even "obese," according to BMI standards, doesn't necessarily indicate a person who "looks fat." Healthy = attractive!