Late last month, a National Cancer Institute study published in the New England Journal of Medicine was given a lot of unskeptical press coverage.
This report, from the AP’s Alicia Chang, is typical in its gloom-and-doom prognosis:
Being a little overweight can kill you, according to new research that leaves little room for denial that a few extra pounds is harmful. Baby boomers who were even just a tad pudgy were more likely to die prematurely than those who were at a healthy weight, U.S. researchers reported Tuesday.
Fortunately for overweight people, the NEJM study is pretty awful, combining bad methodology with dishonest interpretation. The results of this NEJM study, if honestly reported, show that overweight people on average live as long or longer as “normal” weight people; and that the one group of overweight people who did seem to have a significantly elevated risk of mortality, were overweight 50-year-olds who lost weight.
Expect multiple “Alas” posts criticizing this NEJM study. Starting us off is a commentary by Linda Bacon, quoted here with her kind permission.
New Weight Scare Based on Faulty Analysis
by Linda Bacon, PhD, Nutrition Researcher and Professor, NAAFA member
At least 400,000 Americans die of overweight and obesity every year, making it soon to surpass smoking as the leading cause of preventable death [1]. At least that’s what the Centers for Disease Control (CDC) told us.
But an updated federal report, published last year in the Journal of the American Medical Association (and reported in the Late Spring 2005 NAAFA Newsletter), acknowledged that the previous analysis suffered from computational errors [2]. In fact, obesity and overweight only result in an excess of 26,000 annual deaths, far fewer than guns, alcohol or car crashes. And separating overweight from obesity reveals further interesting information: “overweight” people live longer than “normal” weight people.
The data weren’t surprising to those of us who study these issues. This is not an anomaly, but consistent with many other investigations. That it came from the CDC and got published in JAMA were the real astonishing facts.
We waited for the backlash. Fear-mongering about weight is worth billions to industry and is consistent with government policy. Few stand to gain from the news that overweight is benign, if not beneficial. The backlash has been slowly building, and recently came out full force in a highly publicized study published in the August issue of the New England Journal of Medicine [3].
The front page leader in my local paper loudly proclaimed: “Just a few extra pounds is bad for you” and the article title reinforced the message: “Study finds risks for the barely overweight.” Turn to the original report, and you find a consistent conclusion in the abstract: “excess body weight during midlife, including overweight, is associated with an increased risk of death.”
But before you dust off those diet books, let’s take a look at the data itself. The authors worked hard for their conclusion. They examined records from over a half million AARP members that had been surveyed over a ten year period. What they found was entirely consistent with the earlier JAMA report: “overweight” people had the lowest mortality risk. But that wouldn’t serve their purposes. NEJM’s press release wouldn’t look nearly as attractive with that headline.
So they subjected their data to numerous manipulations before finally arriving at a suitable conclusion. First they threw out data on people who were smokers or former smokers. Nope, still shows overweight as benign. They hid this with a sleazy method: using only the top (BMIs of 23 to 24.9) of the “normal weight” group compared to the whole of the “overweight” group.
Then they found an even more creative trick. When they asked participants – some of whom were in their 70s – what they had weighed at the age of 50, they hit paydirt: at last, overweight – at midlife – was associated with increased risk, albeit modest. This will grab the headlines. No need to highlight that we had to whittle our data down to about 5% of the original sample to get this result! (That 40% of the participants chose to leave the question on recalled weight blank should give some indication of the ability of people to accurately report this information.)
Their paper is weak for many other reasons: they had a very low response rate (18%) from a sample that is not nationally representative; their data is based on self-report, which is known to be inaccurate; adjustments for potential confounders were weakly conducted; the list goes on. And they neglected to note another important conclusion: weight loss is associated with a significant increased risk of death for middle-aged “overweight” people.
Come on, New England Journal of Medicine. We expect scholarship, not propaganda.
References
1. Mokdad, A.H., et al., Actual causes of death in the United States, 2000. Journal of the American Medical Association, 2004. 291: p. 1238-45.
2. Flegal, K.M., et al., Excess deaths associated with underweight, overweight, and obesity. Journal of the American Medical Association, 2005. 293(15): p. 1861-7.
3. Adams, K., et al., Overweight, Obesity, and Mortality in a Large Prospective Cohort of Persons 50 to 71 Years Old. New England Journal of Medicine, 2006. 355(8): p. 763-8.
[Crossposted at Creative Destruction, where even the anteaters are covered in chocolate. If your comments aren’t being approved here, try there.]
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It’s appalling to think of how much damage is done to millions of people through this fear-mongering propagation of misinformation and propaganda. Thanks for publishing Linda Bacon’s commentary. Looking forward to further criticism of the NEJM debacle.
Thanks. It’s scary how overwraught the fat fear is.
I remember after reading this study thinking that they really searched hard to find any area in which people who were “overweight” (as opposed to obese) did worse than people who were “normal” weight. They eventually found one, but the data was so obviously confounded that it didn’t seem likely to be meaningful. I meant to email you to point the study (and some of the flaws) out, but never got around to it (mea culpa). Glad you posted on it.
I would caution, however, making too much of the distinction between “overweight” and “obese.” First off, neither state of being is voluntary. Second, many people were pushed over the line (and into ill health) between “overweight” and “obese” due to repeated attempts at weight loss, and yet are most likely to be pressured into trying even further weight loss attempts, even by people who acknowledge that the “overweight” have generally superior health.. Weight loss attempts of any kind are no more successful, safe, or reasonable for the “obese” than they are for “overweight” people.
And, we’d need at least a couple of generations to know what the normal sizes and weights of human beings are when freed from the bizarre impact of weight loss attempts. Many human beings in a world without weight loss attempts would likely still fall in the “obese” catagory simply as their normal body size, even if the numbers of “obese” people would fall with the removal of weight loss attempts from the culture. And, since the “obese” are also the people most directly harmed by weight loss attempts and all the accompanying hatred and lack of access to opportunity and services, we have no confirmation that being genetically “obese” is somehow abnormal or intrinsically undesireable or life threatening. We gain weight more easily than anyone else, and we’ve been hounded and nagged and threatened into doing precisely those things that cause weight gain; it’s a wonder there are any “obese” people in this culture still left alive at all. Give us a couple of generations to try living normally before you condemn us as abnormal or doomed.
The situation for the “obese” is the same as for the “overweight” or anyone else. We’re human beings, equally as valuable as anyone else. We have the right to respect, equal access, and absolute autonomy in medical decisions. Let’s not make the mistake of creating a new “paper bag society,” where the people who are fat, but not too fat, are seen as somehow better or more normal or better for society than the fattest people.
[sarcasm]Sorry. No can do. Why, don’t you understand how painful it is for us to look at you ? [/sarcasm]
Beyond the “paper bag” issue, there’s also the fact that as these sort of bullshit articles get more and more media play, any possible valid distinction between being “overweight” and “obese” disappears more and more. Extreme notions of what’s right and what’s wrong tend to drive out attempts at moderate opinion.
[sarcasm]The great thing about all those crash diets and stomach-stapling surgeries is that they make it much easier for fat women on a budget to buy clothes.[/sarcasm] I went looking for some office-appropriate wear on ebay last year. After awhile, I lost track of how many sellers went to the trouble of explaining that they (or their daughter, mom, friend) had had “the surgery” and now didn’t need the fat clothes anymore. I wonder what compells people to share that information with a total stranger at an online auction house. [sarcasm]I have to get started on my thank you note to the diet industry now. My new used office wear looks great.[/sarcasm]
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Linda Bacon derides some important controls for such an experiment as this (though not for their inclusion but rather the reasons for their inclusion); such as controling for confounding factors like smoking. She does bring up the bigger problems with the report. I’d say the biggest is how they do their normalization, where by they try to hide that within the “normal weight” BMI categories there is as large an increase in mortality rate from their standard as their is between “overweight” BMI categories. Even taking that into account, the end analysis shows women fairing rather poorly. She gets at some reasons in her last paragraph as to why that data is to be taken with a salt lick however. Even looking at the data they provide though, the confidence intervals are fairly variable and overlapping between “normal weight” and “overweight” though it does suggest a trend.
My biggest reservation is the authors leave some of the most important data unshown. Dr. Bacon mentions the decrease weight factor (something which I agree with the authors of the paper on in regards for it potentially being confounding due to association of illness and weight loss, though that could be internally controlled for too if the study is good enough). However, they also leave unshown data from the total cohort that they say agrees with the data from those that gave their recalled weight at 50. That omission leaves me rather dubious, since if the total cohort provided consistent data they should have had no reason to use recalled data.
It is very obvious in their text that the data is being built by the conclusion, instead of the conclusion being built by the data. Bad science.
“Give us a couple of generations to try living normally before you condemn us as abnormal or doomed.”
Just a note in case it wasn’t clear — that “you” in that sentence does not refer to anybody in particular, other than that same amorphous “them” responsible for all those other cultural attitudes and assumptions [Insert something McLuhanesque here.]
“Enlightened modern types, by which we mean those who invariably do what they’re told when they hear the words ‘It’s good for you’ (and who probably used to remind the teacher to give out the homework assignment)…know that after years of merrily feeding our faces, we’ve learned that most of what we’ve been feeding them has been killing us. After all, aren’t most of the people who have ever lived dead? Must have been something they ate.”
–Chris Maynard and Bill Scheller, “The Bad For You Cookbook”
Seriously, besides everything else: Don’t you get the impression from studies and people like this that there is something vaguely shameful about dying at ALL? like, you know, clearly if people would just TRY HARDER, they could’ve avoided this. tsk.
“Eat, drink, and be fucking merry,” you know? And maybe try and be a little bit fucking kinder to your fellow critters. Share some of that food, if you’re that concerned about it being too much. and let it the fuck GO already.
you know; if things keep going the way they’re being predicted to by some of our direr and dourer voices, over the next o i don’t know, half- century or so? i have a feeling that the whole “thin is in!” bit will, at least, no longer be something people have to fret about. on account of, if famine and so forth become “in” in this our supposed “First World,” why, I predict a remarkable turnaround in whatever’s left of the fashion industry: fat is attractive and HEALTHY! hey, imagine that: enough to frigging eat in the damn first place!
Wow. Its a good thing this study has come out. Now we can develop a health-industry infrastructure whose only purpose is to encourage weight loss. I’m sure that will work.
All of these constant studies seem to gleefully ignore the fact that this is the status quo opinion. This is the dominant view point in our country. This has been the guiding philosophy of all medical treatment of fat (and thin!) patients for decades. And what have the results been? They’ve had their day. They do nothing but offer an endless parade of failing “treatments” intending to turn fat people into thin people. The only thing they’ve been shown to do is to make people fatter. Weight loss doesn’t make people healthier. It doesn’t make people happier. It doesn’t even make people weight less! It has a success rate that wouldn’t be tolerated for experimental, last-ditch treatments of terminal cancer. Its time we tried something else. Drug dependancy, disordered eating, and organ amputation have all been exposed as insufficent at best and horrificly detrimental at worst. This must not go on.
First: Does anyone have a full text link to the study? The NEJM link is fee only.
First: If you are going to subject the studies to careful analysis because you believe the medical collective is biased, you should also pay attention to the background of Linda Bacon, cited above. All things being equal, I generally suspect the CDC is going to provide more accurate statistical analysis than someone from the NAAFA. I look forward to reading the study myself, if I can find a link.
Science is fairly decent at this. If obesity is shown to be healthy, then doctors, at least, will admit it. OTOH if it shown to be UNhealthy then doctors will admit that, too.
Um, did I miss that study? There are lots of reasons people get fatter. Eating less and exercising more are not usually the reasons, though.
Relative to what? It’s unhealthy to be anorexic. But the world is not divided into fat people and anorexic people. There’s a large middle ground.
I have read a lot of stuff over the years which links obesity to a variety of conditions ranging from shortness of brreath to joint and back problems to sexual isssues. I am not sure what the top research is on the field. But I would be VERY surprised if weight was unrelated to health.
Overweight is trickier. Going up one point on the BMI from “normal” to “overweight” doesn’t instantly transform one into an unhealthy person. And going DOWN one point from “obese” to “overweight” dooesn’t make you healthy, either. But one cannot get to obesity (which IS known to be unhealthy) without going through “overweight” en route. If one can avoid becoming overweight or “very” overweight, one also avoid becoming obese.
I’m not sure this is entirely true. One can make an excellent argument that weight SHOULD BE unrelated to happiness, seeing as fat people are treated poorly by society. There’s nothing “innately unhappy” about weight gain. That said, pretty much everyone I know who has lost weight has felt happy about it.
Well actually, weight loss DOES make people weigh less, or it wouldn’t be weight loss.
Yes, and people who don’t manage to lose weight don’t die as a result. It’s a poor analogy.
The reality is that weight gain can be bad but not be as bad as, say, cancer. And if it’s not as bad for you, then 1) it’s less important to cure, and 2) you’re willing to take less risk to cure it. It doesn’t mean weight gain is good, though.
Insufficiency is not an argument to stop something, as you surely know. And those things which are exposed as detrimental are changed. What do you suggest as an alternative?
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You can read the study here (pdf link). Shhh.