According to the new research appearing in the July 26 issue of The New England Journal of Medicine, obesity isn't just spreading; rather, it may be contagious between people, like a common cold. Researchers from Harvard and the University of California, San Diego, reviewed a database of 12,067 densely interconnected people — that is, a group that included many families and friends — who had all participated in a major American heart study between 1971 and 2003. The participants met with heart researchers every two to four years. It was that information the NEJM authors mined to explore obesity in the context of a social network.
According to their analysis, when a study participant's friend became obese, that first participant had a 57% greater chance of becoming obese himself. In pairs of people in which each identified the other as a close friend, when one person became obese the other had a 171% greater chance of following suit. James Fowler, study co-author and a political scientist at UC San Diego says that it's not just that people who share similar lifestyles become friends, He and co-author Nicholas Christakis of Harvard Medical School considered the possibility — and were surprised. For one thing, geographic distance between friends in the study seemed to have no impact: friends who lived a 5-hour drive apart and saw each other infrequently were just as influenced by each other's weight gains as those who lived close enough to share weekly take-out meals or pick-up basketball games. The best proof that friendship caused the weight gain, says Fowler, is that people were much more likely to pattern their own behavior on the actions of people they considered friends — but the relationship didn't work in the other direction. If you had named another person as a friend, and your friend became obese, than you were more than 50% more likely to get fat too. But if your friend had not named you as a mutual friend, and you became obese, it would have no significant impact on your friend's weight.
The obvious question is, Why? Spouses share meals and a backyard, but the researchers found a much smaller risk of gaining weight — a 37% increase — when one spouse became obese. Siblings share genes, but their influence, too, was much smaller, increasing each other's risk 40%. Fowler believes the effect has much more to do with social norms: whom we look to when considering appropriate social behavior. Having fat friends makes being fat seem more acceptable. "We get to choose our friends," says. "We don't get to choose our families."
Fowler and Christakis say that the contagion-effect should hold just as much for weight loss as it does for weight gain. "I would hope this influences individuals to get friends and families involved in decisions about health," Fowler says. After all, he says, a weight-loss plan may be more effective if the people closest to you are on board. And, if you're successful, your good health will help others achieve a healthy weight too. The impact extends not just to your friends, it turns out — but also to your friends' friends, and even to their friends.
注（1）：本文选自Economist, 07/25/2007
注（2）：本文习题命题模仿对象为2002年真题Text 3。
1． The following are factors causing obesity according to the researchers, EXCEPT that_______.
[A] similar lifestyles among some people
[B] geographical distance between friends
[C] one’s closest friend being fat
[D] being mutual friend with fat guys
2． If can be inferred from the text that _______.
[A] allt he participants have no connection with each other
[B] all the participants have heart diseases
[C] researchers meet the participants irregularly
[D] it is a long-term study
3． The experiment involving both family members and friends is because _______.
[A] researchers fail to find a more diverse sample
[B] researchers have different hypotheses for family members and freinds
[C] researchers can meet these people regularly
[D] researchers can compare the results
4． We can draw a conclusion from the text that _______.
[A] When people choose friends, obesity comes at the first standard
[B] The friends of a fat person must all be very fat
[C] Familiy plays a more important role of affecting obesity
[D] The contagion-effect of obesity also sheds light on weight loss
5． From the text we can see the writer seems _______.
[A] objective
[B] optimistic
[C] sensitive
[D] gloomy
篇章剖析
本文就肥胖在人与人之间的影响和传播性这一问题展开了论述。第一段提出了话题，并说明了研究的背景和方法；第二段展示了研究结果，并结合实例进行说明；第三段讨论了家庭关系和朋友关系对于肥胖的不同影响极其原因；第四段指出了该研究的实用性和将对人们产生的影响。
词汇注释
obesity [Eu`bisiti] n. 肥胖, 肥大 take-out n. 外卖
contagious [kEn`teidVEs] adj. 传染性的, 会感染的 spouse [spauz] n. 配偶(指夫或妻)
dense [dens] adj. 密集的, 浓厚的 norm [nC:m] n. 标准, 规范