Obesity-friendship research offers valuable food for thought

BOSTON — Let me rise (from the breakfast table) in defense of Nicholas Christakis and James Fowler. The doctor and the political scientist were used to having a rather meager portion of academic attention. But now their cup and their inbox runneth over with charges of hate-mongering, size-ism and fat discrimination. They've been held personally responsible for increasing the social ostracism of the obese.

The research documenting the spread of the obesity epidemic from friend to friend to friend leapt from the peer-reviewed, sober annals of the New England Journal of Medicine to the front pages of newspapers everywhere. The message was that fat is contagious. This was reinforced by catchy and catching headlines that declared: "Your Friends Really Are Making You Fat," and "Your Friends May Be to Blame" and ... well, you get the idea.

Christakis and Fowler did not use the word "contagious" in their paper. Nor did they use the word "blame." But crunching the numbers of a long-term study of people who live in a suburb near me — yipes — they found that people were more likely to become obese when a friend became obese. And most likely to upsize when a close mutual friend went up. Their point was that social networks counted a lot more than family or neighbors.

Christakis has now responded to some 1,000 e-mails, explaining that he does not believe the first step to weight loss is cutting friends out of your menu. Indeed at a body mass index he'll describe only as "under 30," he doesn't want to be dropped by his best friend: BMI of 21.

But if we can get past the "friends make you fat" tagline, there are some fascinating tidbits in this statistical buffet. Consider the notion that people gained weight in tandem with friends even when they lived far away. This led the researchers to conclude that the friendship factor was not just a matter of behavior. It isn't just that birds of a feather chow down together or order dessert together.

Rather, the researchers speculate, close friends fundamentally affect our point of view. They create a norm. Professional anorexics such as Kate Moss, Calista Flockhart and Victoria Beckham may present an incredibly shrinking ideal. But in real life we measure ourselves against our friends. Inch for inch.

It should be noted that only friends of the same sex have this effect on each other. And one of the tantalizing hints in the research is that male friends may be quietly sizing each other up more than do female friends. Friends also size each other down, say the researchers, but since the throw weight of our society is on an upward trajectory, there were fewer of those to count.