a culpa é de vocês...
Can Your Friends Make You Fat?
By JENNIFER LEVITZ
July 26, 2007; Page D1
Friendship offers support, laughter -- and the occasional spare tire.
Just ask Jamie Tighe, a 35-year-old stay-at-home mother in Franklin, Mass. In college, Ms. Tighe and her friends "all gained weight together." Then she and her best friend added more poundage over Margaritas and chips. Her appetite -- and her avoirdupois -- spread to her husband, Kevin Tighe, who she says had been "rip cut" when they married.
"He just started putting on the weight," she says. "He didn't even care. He'd call it his Buddha belly and make fun of it, rub it." Mr. Tighe, a 38-year-old technology salesman, says it's true. "I ballooned up," he says. "If someone else is doing it, you don't feel as bad about it."
The Tighes' mutual overeating isn't unusual. A study in this week's New England Journal of Medicine finds that social networks have an even greater effect on chances of becoming obese than genes do. The findings may help explain why obesity is rising in America despite widespread dieting and other weight-loss techniques, and why people's best efforts to slim down on their own are so often short-lived. They also suggest that public health initiatives to fight obesity should take social networks into account, and work with overweight people in groups, as organizations such as Weight Watchers International Inc. have done for years.
Dr. Nicholas Christakis at Harvard medical school, lead author of the study, says the results indicate that behavioral "norms" shift depending on how people in a social circle look and act, even if they only meet once a year. "People might say, 'Look, Christakis is getting fat. It's okay for me to be obese as well." Social contacts propelled weight gains even among individuals a thousand miles apart, indicating that social proximity overrides geographic proximity.
"It's become very fashionable to speak of an obesity epidemic," says Dr. Christakes. "But we wondered, in fact, is obesity really an epidemic, with person to person transmission? Was there a kind of social contagion?"
The study found that indeed there was. A person's chance of becoming obese jumped 57% if he or she also had a friend who became obese during a given time. If one adult sibling became obese, the chance that the other would follow suit increased by 40%. These findings were particularly true if siblings and friends were of the same sex -- since, researchers say, people are more influenced by those they resemble than those they do not. Indeed, the chance of becoming obese rose 71% if it was a same-sex friend who gained the weight.
The study examined 12,067 people who underwent repeated body measurements over 32 years as part of the Framingham Heart Study, considered the crown jewel of epidemiological studies.
Over the years, each participant in the heart study was asked to list close friends and workplace contacts to allow doctors to track them down. Many of these friends, it turned out, were also part of the study, so their information was available to researchers.
From these contacts, researchers examined 38,611 family and social relationships, charting associations between a person's weight gain and the weight gain among his or her social circle, including relatives, friends, and co-workers.
Among married couples, the study found, if one spouse became obese, the likelihood that the other spouse would do the same increased by 37%. The study also suggested that most people don't keep up with the Joneses when it comes to weight gain since it found no effect from the obesity of neighbors who aren't part of the social network.
The study is part of a larger trend in science and social science to examine the effect of networks, from the role that interconnected neurons play in cognition, to even networks of terrorism. There's evidence, for instance, that political attitudes are shaped by social circles, and that when it comes to sexual behavior, teens are more influenced by their immediate friends than by the most popular group at school or by the media.
"Networks are really important for the transmission of ideas and values," says Katherine Stovel, a University of Washington sociology professor who studies networks. "People come to resemble one another." But, she cautioned, "I don't want anybody to read this and think about dropping friends because they're fat."
MORE
• Harvard's statement
• Video interview with Nicholas ChristakisTraci Joyce, a 39-year-old lab technician at a regional cancer center in Greensboro, N.C., says she and many of her co-workers need to "lose a few pounds." Yet they push pastries, cookies, cakes and chocolate turtles on each other. "They'll try to sabotage you sometimes," she says. "Oh come on, you can have some. It'll be alright."
Some doctors are excited about the new obesity study from a public health perspective because if weight gains can spread through a network, then presumably, so can healthful habits. Medical and public-health interventions in obesity might be more cost-effective than previously thought, the study's authors wrote, "since health improvements in one person might spread to others."
In an editorial in the New England Journal of Medicine, Albert-Laszlo Barabasi, of the University of Notre Dame's Center for Complex Network Research, urged the medical profession to take the network effect seriously. He wrote that "the role of links and connections does not stop here," and that such studies "should start to affect medical practice."
Many communities are already harnessing the force of networks to reduce obesity. In Guilford County, N.C., where 62% of residents are obese, local health officials held a community-wide weight loss program this spring. Called the Guilford County Mayors' Challenge, the program joined together citizens who wanted to lose 10 pounds in 10 weeks. The group chatted online about exercise routines, and exchanged healthful recipes. Ten weeks later, 150 people had shed 1,450 pounds.
Toni Anzalone Zirker, a 50-year-old substitute teacher in Greensboro, Guilford's county seat, says she originally tried to lose weight with a group of friends. "I tried to call several friends -- they didn't follow through," she says. But when she joined the Mayors' Challenge, she found an instant support group, which motivated her. Someone would write online, she says, "I gotta take off this pork belly." She says she'd think, "yeah, I can relate to that."
"You didn't feel all alone out there," she says.
And ultimately, a group setting rescued Jamie and Kevin Tighe, the Franklin, Mass., husband and wife who had literally grown as a couple after marriage.
Ms. Tighe, struck with the desire to be healthy for their two daughters, started dieting first. Mr. Tighe was uneasy with her new attitude. "He'd say, 'Oh god, you're not fun anymore," she says. "You don't get the appetizers."
Mr. Tighe says he was merely feeling guilty for eating fatty foods while she was eating salad. But sure enough, as she began to trim down, he wanted to do the same. The two became active in a chapter of Weight Watchers; Ms. Tighe leads local meetings, and both are at healthy weights. Mr. Tighe, who's shed 60 pounds since 2005, says having a support system "got my butt off the couch."
Write to Jennifer Levitz at
jennifer.levitz@wsj.com
"I used to be on an endless run.
Believe in miracles 'cause I'm one.
I have been blessed with the power to survive.
After all these years I'm still alive."
Joey Ramone, em uma das minhas músicas favoritas ("I Believe in Miracles")