Obesity is a big problem that needs big solutions, and Facebook may be coming to the rescue.

In a way that’s never been possible before, people can record their interests, habits and daily activities that at first blush might seem to have only trivial meaning. But such data can be accessed by almost anyone (depending on privacy settings, of course), and that includes researchers. Scientists are turning to Facebook as a way to track how obesity trends, for example, correlate with geographically-specific trends in diet and exercise,  and hope that such information can lead to more targeted ways of reversing the obesity epidemic.

The researchers, from Boston Children’s Hospital, aggregated data on Facebook users’ interests and discovered that the higher percentage of people with interests that related to healthy and active lifestyles in a given area, the lower was that region’s obesity rate. The opposite was true for areas with a large percentage of people with Facebook interests that related to television, for example.

To come up with the link, the scientists studied what national Facebook users posted on their timelines, what they “liked,” and what they shared with their friends to come up with nation-wide associations.They also looked specifically at users within New York City and found similar trends at the neighborhood level, documenting that communities with more residents expressing interest in healthy lifestyle behaviors and products showed lower obesity rates than those where residents tended to show more interest in television shows.

Nationwide, obesity rates were 12% lower in areas where the highest percentage of Facebook users had exercise-related interests. In New York City, Coney Island, which had the highest percentage of users with activity-related interests had a 7.2% lower obesity rate than Southwest Queens, which had the lowest percentage of Facebook users with active interests. The power of the strategy, the scientists said, lay in the social media’s ability to focus on both national as well as local trends.

“Definitely in public health [Facebook] is a great source for identifying where we should target public health interventions,” says Rumi Chunara, an instructor at Boston Children’s Hosptial and Harvard Medical Center and author of the study, which was published in the journal, PLOS ONE. “At the same time, because this is a real time source, we can also evaluate the status of other interventions.”

Such assessments may be social media’s most important contribution to fighting the obesity epidemic, says experts, since many of the current strategies to reverse the tide aren’t working. “In order to combat obesity, we have to look beyond what we have been doing because it really hasn’t worked, which is the traditional diet and exercise,” says Dr. Jennifer Li, a professor of pediatrics and division chief of pediatric cardiology at Duke University Medical Center in Durham, N.C.. “One way of reaching people is through social media since most people are connected through Facebook and Twitter and various social media. Li lead an American Heart Association study on using social media to fight childhood obesity.

“We have to look at ways to reach out to people, and one of the things you can look at is how people cluster,” she says. “People cluster in social media just as well as they do in real life. If you smoke, your friends are more likely to smoke. If you’re obese, you’re friends are more likely to be obese. If you can make an impact on the group, you can have a ripple effect.”

Some programs are already exploiting the power of the interactivity of these networks; Weight Watchers, for example, has an online network of dieters, with apps and updates in addition to their traditional meetings. Programs like Weigh2Rock is another weight loss website targeting overweight kids via chat-rooms with dietitians.

“These can be used as a reinforcement tool if [programs] use the social media and websites to get supplementary information like diet advice and exercise advice to users. If there’s reciprocal interactions between the group and whoever is managing it, you can build in support,” says Li.

The very feature that makes these strategies so powerful, however — the openness and transparency of the connection that users feel — could also make them vulnerable to exploitation. While healthy brands and weight loss programs abound on Facebook and Twitter, so do less qualified programs and not-so-healthy brands that increasingly capitalize on the massive online audience. Jennifer Harris, the director of marketing initiatives at Yale Rudd Center for Food Policy and Obesity, studies food marketing aimed at children and teens, and has focused on how brands use social media to target them.

“There are so many children on Facebook especially, and the food companies all have Facebook pages that kids can ‘like,’ and when they ‘like’ the page, they are constantly seeing posts on their newsfeed and their friends can also see these posts from the companies,” says Harris. “Unfortunately, almost all of them are unhealthy food. If you look at the top 20 brands on Facebook, Facebook is number one, but then Coca-Cola is next with more than 60 million likes, followed by other brands like Oreos, Red Bull, Skittles, Pringles. These are all in the top 20 food brands on Facebook.”

Harris says fast food restaurants and energy drink companies are also actively using social media to target teens by creating YouTube videos. By enhancing the appeal of the posts and videos with lively humor and music, the companies are appealing to kids ‘and teens’ tastes and increasing the chances their hits will be shared with their friends.

“For teenagers, a message that comes from your friend is much more powerful than something that comes from a parent or teachers, so that’s another reason we think social media is used by companies that target teens,” says Harris.

Unfortunately, while weight loss organizations and healthy lifestyle brands use social media too, their efforts have hardly been as appealing or as viral as those of the less healthy ones. “I think there is an opportunity [for healthy organizations to reach teens with social media], but with kids it has to be fun and entertaining, and [it’s hard] to make “eat healthy” messages fun and entertaining. I think we are just not as good at designing those messages as the companies that market to kids are,” she says.

There’s also the double-edged sword of relying on a social media outlet, which requires children to be online, to promote healthy, active lifestyles. Too much screen time can often contribute to a more sedentary lifestyle, so advocates of physical activity recognize their efforts have to balance that risk with the benefits of reaching people, especially young children, in a way that appeals to them.

“I think the mainstay of weight loss is diet and exercise, and a very important thing is prevention and education in the schools. I think social media is a way to reach a lot of people, but it doesn’t become a substitute for diet and exercise,” says Li. “It is a way to have people be incentivized, because a lot of people communicate right now through social media. It is not a replacement, but it reinforces behavior.”

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Alexandra Sifferlin

Alexandra Sifferlin is a writer and producer for TIME Healthland. She is a graduate from the Northwestern University Medill School of Journalism.