I just finished reading a book that's been out for several years but that I ignored until recently, when I thought I might need a corrective to all the diet books I read last year while I was losing weight: The Obesity Myth by Paul Campos. It's been a while since I deliberately read something that I expected to disagree with -- a practice I recommend heartily!
I was surprised to find that the book was in more than one way a wake-up call for me.
The basic thesis of the book is that our public policy towards obesity, and the amount we spend in public and private dollars to combat obesity, doesn't make sense for three reasons.
Number one: there's no credible evidence that obesity in and of itself (except at the extremes) causes health problems.
Number two: there's no credible evidence that losing weight in and of itself makes obese people healthier.
Number three: We're not getting much bang for our buck anyway, since the money and effort we've poured into the goal of getting people to lose weight is not resulting in weight loss.
I will begin with several significant caveats. I am not entirely convinced by Mr. Campos's review of medical data. There is not that much of it; I would like to see a much more thorough and detailed cataloguing than is present in this book, one much more like Gary Taubes' analysis in Good Calories, Bad Calories. I am also certain that some of Campos's data points raise questions that require answers before one can come to a conclusion. (One example: he writes that, excluding extreme thinness and fatness, life expectancy increases as you go from lower to higher BMIs. I thought: Now wait a minute -- life expectancy also increases as you get older, and people gain weight as they age, so shouldn't there be a correlation there anyway?) Third, he seems to sort of selectively criticize and praise the practice of controlling for confounding variables. I agree that this statistical tool can be used judiciously or maliciously, but Campos does not explain why he says it's justified here and not there. Has he proven that "there's no credible evidence" that obesity causes illness? I don't think so.
However, I think he does succeed in showing something a bit less ambitious: that the evidence is not nearly as strong as most people assume it is based on media reports and public policy recommendations. Five arguments he made struck me as very persuasive, if they are true, of this less-ambitious thesis. I feel I have to add that caveat because I think Campos needs more evidence to demonstrate that they are true. But if they are true, I agree with him that they call into question the obesity-health connection.
(1) To demonstrate that obesity causes health problems, most of the studies had to exclude smokers. (He says this isn't legitimate; I say it is; but regardless, the following point still stands.) After you exclude smokers and maybe a few other classes of people, the number of deaths in the studies are small. Nonsmokers in one study had a less than 1-in-600 chance of dying of cardiovascular disease; thinner nonsmokers were less likely to die than fatter nonsmokers, but the number of excess deaths attributable to obesity alone is perhaps not high enough to justify the effort we're putting into combating obesity. At the very least, the harm of obesity is likely dwarfed by the harm of smoking. Which do you suppose our country spends more on: attempting to lose weight and get people to lose weight, or attempting to quit smoking and get people to quit smoking?
(2) Public policy advisory boards have an astonishing level of conflict of interest. It goes beyond the level of "this study was funded by that industry which has a stake in the findings." For example, he says that a claim of a strong international consensus that BMI>25 was based largely on the report of a World Health Organization panel that "consisted entirely of physicians who run weight loss clinics." Even if you assume a good-faith effort, could such a group really be objective?
(3) Campos says that studies that purport to show a connection between weight loss and improved health have not adequately controlled for the effect of improved nutrition and increased physical activity; and news reports fail to distinguish this effect too. Campos gives an example of a study where participants significantly increased their physical activity and as a result both lost a few pounds and improved some measures of their physical health: the media reported it as "losing a few pounds can improve your health." It is now very well established that, independent of your weight, physical activity makes people healthier. (I wrote about this in my post about reasons to exercise.) Because of that, it's obvious that a study purporting to show that obesity causes poor health must control for physical activity. Campos says that many of the studies don't have that control.
(4) Taking all the methods together, the act of losing weight introduces significant health risks that have not been adequately compared to the risk of not losing weight. For instance, he claims that bariatric surgery is shockingly dangerous (the risk of death within a month of the surgery is somewhere between one in 20o and one in 50!). Is it really proportionally dangerous not to have bariatric surgery, especially at the lower-BMI end of the market? He says there are health risks associated with traditional methods of weight loss as well.
(5) Being "BMI-normal" or less appears to cause some serious diseases that obesity protects you from. Osteoporosis, which can lead to deadly hip fractures, is one such disease; there are others. When you include these "diseases of mild thinness," does the relative danger of mild obesity start not looking so bad?
Since it's true that physical exercise really is well established as something that improves health, it's apparent to me that it's dangerous to suggest "You should exercise to lose weight, because the weight loss makes you healthy." Physical exercise is not actually that good at bringing about weight loss. If someone starts exercising to lose weight for their health, they could really be improving their health and yet not see a weight loss; and will they then conclude that it's not doing any good, and so quit? Or will thin people dismiss exercise because they don't think they need to exercise to be thin?
* * *
Not all of the book is about the medical research. A large part of it is about the social pressure to be thin. This is the part of the book that, for me, was a wake up call. Because I've probably been contributing to it a bit over the past year, as I chronicled my own struggles with weight loss. I hope on the whole my writing has been positive, because I firmly believe that physical activity and well-balanced, not-excessive nutrition are worthy goals in and of themselves, even if they don't result in thinness, and I want my writing to have reflected that. Still, I measured my success last year largely in the pounds that came off the scale, and I'm a bit more aware that I emphasized the number too much.
Even in my personal experience, Campos's points ring true. I've been telling people that I've never felt better since I lost the weight -- but maybe I feel better because I'm so much more physically active, and the weight loss is just a side effect.
And then there is the lengthy discussion of why we criticize obesity so much. We say it's about health, but is it really? Particularly if the medical evidence against it turns out not to be so damning? Campos makes a strong case that it's about the need for us to have some kind of social pariahs among us, a need to feel superior to others. (Hoo boy, that hit home. Consider this post. And consider that it was after I started to lose weight that I started to write that I was "conquering gluttony." Look, I'm getting thinner! It proves I'm becoming a better person!)
A point I found especially interesting: Campos, a Mexican-American, argues that the freedom to look down one's nose at fat people has functionally created a way for elite, highly-educated white people to continue to sneer at low-income black and Hispanic people, without having to feel guilty about it:
Precisely because Americans are so repressed about class issues, the disgust the (relatively) poor engender in the (relatively) rich must be projected onto some other distinguishing characteristic... In 2003, any upper-class white American liberal would be horrified to imagine that the sight of, say, a lower-class Mexican-American woman going into a Wal-Mart migt somehow elicit feelings of disgust in his otherwise properly sensitized soul. But the sight of a fat woman -- make that an "obese"-- better yet a 'morbidly obese' woman going into Wal-Mart ... ah, that is something else again.
He has got a real point (made only clearer by the fact that some upper-class white people would be disgusted merely by the mention of the Wal-Mart, without any reference to obesity at all).
Race intersects with obesity culture in another way I wasn't aware of. According to Campos, girls and young women in the U. S. who are black or Hispanic are much more likely to have a positive appreciation of their own bodies than are white girls. They are more likely to evaluate their self-worth independently of their appearance. They are also likely to have a higher BMI. And (this is the kicker) at least for African-American women, the denonstrated connection between obesity and poor health is even weaker than it is for white women. Campos seems to suggest that public health authorities are actively promoting educational campaigns that will sensitize young black and Hispanic women to the dangers of obesity. If this is true, it is really hard not to come away with the impression that some public health policy amounts to "Let's make black and Hispanic girls feel bad about their weight."
So here's my final word on the book. It's not perfect. It's flawed. It raises questions that go unanswered. I'm not convinced of Campos's thesis. But I think I'm convinced that he raises good points, points that people like me -- who tend toward the weight-obsessed, and who like to tell ourselves that it's "about our health" -- need to read and take to heart. Some of this seeking after thinness is not necessarily healthy, and it's not necessarily virtuous.
Over the months after I reached my goal weight, it took constant vigilance to keep my weight at 108 instead of, say, 112. Is it reasonable for me to fear those four pounds? OK, the truth is I'm really afraid that if I let myself gain 4 pounds, I'll let myself gain 40. Is that a reasonable fear? All my clothes still fit at 112. If I relaxed my diet slightly and became stable at 112, would I be happier or sadder? And does it make any sense at all to be "proud" of my weight loss? Even if it's true that gluttony was a big problem before, am I better off if I replace it with vanity and pride?
I think I came away very convinced of one sentence in the book, one of the principles of the "health at every size" movement: A healthy weight is the weight a person maintains while living a healthy life. To me, that means while being physically active and eating a well-balanced diet in response to real hunger signals. Campos derides the traditional approach, but I disagree. I think traditional "diet and exercise" can help a person create that healthy life; you may have to exercise on purpose in order to get enough physical activity, and you may have to control your eating in order to balance your diet and learn to eat in response to hunger. I did. But it does suggest that the number on the scale ought to have less sway on our decisions, personal and public, and especially on our compassion towards others, than it currently does.