fat redux

Fat Lies
Obesity, laxity, and political correctness.
By William Saletan

Posted Thursday, July 26, 2007, at 5:21 PM ET

Obesity is contagious like a virus. Willpower can't contain it. Stop blaming and stigmatizing fat people.

That's how scientists and the press are spinning a new study about weight gain, published today in the New England Journal of Medicine. The spin is politically correct but medically perverted. The study's findings tell exactly the opposite story: Obesity spreads culturally, individual decisions are crucial, and responsibility and stigma are part of the solution.

How did the story get twisted? Start with the contagion metaphor. The word contagious never appears in the original paper, written by Nicholas Christakis of Harvard Medical School and James Fowler of the University of California at San Diego. But it's all over their sound bites. "Obesity Is 'Socially Contagious,' " said the headline on UCSD's press release. Christakis told reporters that obesity can "spread from person to person like a fashion or a germ" and that "once it starts, it's hard to stop it. It can spread like wildfire." A government official who funded the research concluded, "It takes what was seen as a noninfectious disease (obesity) and shows it clearly has got communicable factors."

These metaphors spread rapidly through the media like … well, like bad metaphors. The New York Times ("Study Says Obesity Can Be Contagious") opened its report with the line, "Obesity can spread from person to person, much like a virus. …" The Los Angeles Times ("Obesity is 'contagious,' study finds") began, "Obesity can spread among a group of friends like a contagious disease," and added that the study showed a "pattern of contagion most often associated with infectious diseases." The Washington Post began, "Obesity appears to spread from one person to another like a virus or a fad. …"

The virus metaphor infected—actually, no, it didn't infect, it simply influenced—the authors' and the media's conclusions. "Treating people in groups may be more effective than treating them individually," Christakis argued. The Los Angeles Times paraphrased one expert's inference that "obesity treatment programs should move away from their emphasis on individual willpower." The Post said the results "lend support to treating people in groups or even whole communities." A warning against "relieving people of responsibility for watching their weight" vanished from the Post's article overnight.

Obviously, from a collective standpoint, it's more efficient to address obesity in a group than in one individual. But just as obviously, groups consist of individuals. And the gist of this study is that obesity did not spread through the sampled population like a virus or any other materially transmitted malady. It spread culturally, individual to individual, through the relaxation of standards of personal discipline.

Many scientists believe that in some cases, viruses literally cause obesity. Others point to genes or environmental constraints, such as fast-food joints, distances too great to walk, and a shortage of parks, sidewalks, and good grocery stores. Research suggests these factors do matter a lot—and to that extent, fat people deserve sympathy, not blame. But such factors can't account for the spread pattern documented in this study. Genetics can't explain it, since having a fat friend was more likely to predict a person's obesity than having a fat sibling was. Environmental constraints can't explain it, since faraway friends made a difference, while next-door neighbors didn't. Availability of food can't explain it, since friends had a bigger effect than spouses did. Nor can sheer imitative eating, since faraway friends had as big an effect as local friends did.

Cross off genes, viruses, environment, and imitation, and the only explanatory factor you're left with is, as the paper notes, each person's "perception of the social norms regarding the acceptability of obesity." In other words, culture. Moreover, the study documents obesity's differential spread not through an amorphous group but through a network. The point of differential spread though a network is that each node—in this case, each person's cultural decisions—matters.

The upshot of the data is that if you find yourself caught in a fattening social network, you have three options. You can resist the fattening norm. You can try to reverse it. Or you can ditch your fat friends.

That doesn't sound very nice. The study's authors certainly don't want to say it. In talking to the press, the Post notes, they "cautioned that people should not … stigmatize obese people." Likewise, an obesity expert from Yale warned the New York Times against "blaming obese people even more for things that are caused by a terrible environment." Fowler cautioned that studies "suggest that having more friends makes you healthier. So the last thing that you want to do is get rid of any of your friends." Christakis added, "We are not suggesting that people should sever ties with their overweight friends. But forming ties with underweight or normal weight friends may be beneficial to you."

Come on. Everything in the study belies these mealy-mouthed conclusions. To resist a fattening norm, you need willpower. To reverse it, you need to promote responsibility, which implies blame. You almost certainly need stigma. And realistically, to add normal or underweight friends to your circle, you have to relegate others who are overweight. That may be bad for your fat ex-friends, who will lose your friendship as well as your thinness. But it's fine for you, since you'll have just as many friends as before.

Maybe it's not nice to speak these truths. But maybe being nice, when you should be speaking the truth—especially to your friends—is the problem.