Dieters who make more connections in online weight-loss communities lose more weight, according to a Northwestern study published Wednesday.

The study, published in the Royal Society journal Interface, is the first to consider the power of social media in weight loss.

In an online program in which dieters joined weight-loss communities, online dieters who logged in regularly, recorded their weigh-ins and “friended” more than 10 other members lost more than 8 percent of their body weight in six months. Users who did not connect with the community as often lost about 5 percent of their body weight, and users with two to nine friends lost almost 7 percent of their body weight in the same amount of time.

“There is an almost Facebook-like social network system in this program where people can friend each other and build cliques,” said McCormick Prof. Luis A. Nunes Amaral, senior author of the study, in a news release. “In this case, we found the larger your clique, the better your outcomes.”

Dr. Bonnie Spring, a Feinberg professor and another author of the study, had access to data from CalorieKing.com’s weight-loss community. Amaral’s lab analyzed this data and uncovered trends.

“In the clinic, we don’t have the ability to connect people with such a large network of others on the same journey to lose weight,” Spring said in a news release. “I was very surprised by how lawfully each step-up in social connectedness translated into greater weight loss. We could clearly see the benefit of the online social network for weight-loss success.”

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