Close clusters of friends are more likely to make an impact on your health choices than distant connections when it comes to social networks, a new study suggests.

Researchers had thought that close groups of friends would just pass around the same old information all the time, and therefore, would not be of help for those trying to change their health habits. It was thought that more distant acquaintances would have a bigger impact because they would bring new ideas to a network.

But now, it appears that those close groups actually provide extra reinforcement when it comes to changing habits, said study researcher Damon Centola, a professor at the Massachusetts Institute of Technology in Cambridge, Mass.

"You normally think if you spread something far away, it can spread faster and faster to new areas," Centola told MyHealthNewsDaily. "But it turns out, in these overlapping shared relationships ... it goes farther and faster through [close-cluster] networks."

Centola defines a "close cluster" as a group of people who all have common ties like a group of friends who all know each other. A "distant tie" is someone who is perhaps just an acquaintance of yours, and may not know any of your friends.

Centola created an online health community to study the behaviors. More than 1,500 people participated in it and were put in two networks the members of one group had only distant ties to each other, but the members of the other were a close cluster. He ran a series of tests to see how many people in each group would sign up for a website that offered health resources.

Fifty-four percent of the people in the close-knit network signed up for the new website, compared with 38 percent of people in the group with more distant ties. Centola also found that the more friends registered for the health forum website, the more likely the person would sign up as well.

Even though Centola's experiment was centered on an online health community, the implications can be used for real-world health behaviors as well, he said.

"These networks can really foster really large-scale population change in health behaviors," he said.

The findings were published in the Sept. 3 issue of the journal Science.