Chewing the fat with my friends

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 hatemongering, sizeism 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: index 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.

All that said, I wonder: Why exactly should we be surprised — let alone irate — that friendship is a factor?

I am the first in my crowd to blame the obesity epidemic on supersizers from McDonald's to the sugar chefs at cereal companies. I have documented the burgeoning bagel, the shrinking playground, the portion-out-of-control restaurant, as well as the genes that dictate new jeans. They are ground zero in the epidemic.

But why resist the notion that this effect is amplified through networks and that the closest friends have something to do with the shape of our lives? We all know teenagers whose sudden desire for a nose ring is not in the DNA but the in-group. We see friends follow each other into marriage and parenthood. And how many times have we been warned that divorce is, um, contagious?

Indeed, Fowler crunched the same numbers to show similar ties between friends and smoking — from starting to quitting. If the smoking research had been published first, would it have kicked up such a fuss? I doubt it. What's unique about obesity as a health problem is that it carries a psychological stigma as well as a risk; it's a matter of beauty as well as diabetes; of hate jokes as well as heart disease.

Of course, Fowler, who is still reeling from the reaction, is really interested in the way social networks operate. The world may judge us one willpower at a time, but this research, he says, "shows how much we are in it together."

I have no doubt that the role of friendship is routinely undervalued. We are treated as if we were isolated individuals or encapsulated members of nuclear families. We forget the connections.

I'm not about to write the Social Network Diet. But for me, the take-home message is not to keep three degrees of separation from a friend's jelly doughnut. It's to remember how much friendship counts ... on the scale of things.

Ellen Goodman's column appears Friday on editorial pages of The Times. Her e-mail address is ellengoodman@globe.com