Photo: Pink Sherbet Photography, Flickr

If your teen is hanging out with kids who are overweight, you might want to keep a close eye on her eating habits. A recent study found that teens' eating and exercise habits were strongly influenced by their friends, and if her friends are fat, it's highly likely that she'll pack some pounds on as well.

These findings, based on results from approximately 5,000 teens, gives the idea of imitative obesity (subconsciously choosing to do things that cause weight gain because the people around you are heavy) a bit more, uh, weight. And we don't believe for a second that this idea only relates to those not old enough to vote.

Researchers say this could also be that teens might be more prone to hang out with others that are a similar size, but they do seem to be influenced by each other's behavior.

Imagine yourself at your favorite restaurant. If you're there with your trainer or a really fit friend, what do you order? Is it different than what you'd order if you went with someone less concerned about calories? If your dining partner wanted to split the fried mozzarella appetizer, would you have the stomach to say, "No thank you"?

Aside from making us more aware of the fact that our food and exercise choices are impacted by our social ties, what does this study have to offer? For one thing, it can help policymakers narrow the focus of weight loss campaigns, particularly those geared toward children and teens. Rather than focusing just on individuals, they can work to target groups of kids together.

Another possibility is that, as kids become better educated about the benefits of healthy eating and exercise, perhaps the fitter kids will start having a positive effect on their heavier friends in the same way the overweight children have affected their thinner friends. It's just as easy to share a good habit as a bad one, right?