09/13/2012 08:12 am ET Updated Nov 13, 2012

I'll Have What She's Having: Eating Is a Contagious Behavior

Have you ever gone to a restaurant with the healthiest intentions -- a salad followed by grilled fish and steamed vegetables -- only to find yourself halfway through a bacon cheeseburger and onion rings? Or, on the other hand, have you ever listened to everyone at your table order a salad with grilled chicken, only to hear yourself echo their order? As it turns out, eating is a contagious behavior. A study published in the New England Journal of Medicine analyzed data from 32 years and found that your chances of becoming obese increase by 57 percent if you have a friend that's obese -- a chance that's even greater than sharing genes.

According to researcher Dr. Nicholas Christakis, "You change your idea of what is an acceptable body type by looking at people around you." So if your overweight friend orders dessert, you assume it's okay to do the same; you're changing your eating habits to mirror those of your overweight friends.

But new researchers have taken a two-way approach to examine how eating patterns can be influenced, hypothesizing that each diner's eating behavior mirrors the other's back and forth. A study published in PlOs One found that women tended to take bites of food at the same time, demonstrating behavioral mimicry. In the study, researchers observed 70 pairs of women who had never met share a meal; they found that mimicry was more pronounced in the beginning of the meal than at the end. The researchers believe that because the women were unacquainted, they attempted to bond by mirroring each other's movements, in just the same way that we unconsciously mimic hand gestures and facial expressions when we try to socially connect.

As for that birthday cake at the office? It doesn't mean you can't join in on the festivities -- if you just can't bear the thought of missing out on a little cake, stick with the three-bite rule and enjoy a little taste of the cake.

What if Mom is a "pusher"? My advice is to let her know that your intentions are not to hurt her feelings and that you love her food, but one serving is enough and you want to take the rest home for lunch or dinner tomorrow. Communication is key.

Your daily game plan: Prepare for daily scenarios in advance -- for example, if you know you are headed to your parents' house for a family dinner, volunteer to bring a healthy dish that everyone can enjoy, and prep your communication strategy ahead of time. (You can even start it beforehand on the phone with Mom, and explain to her your goals and how important her support is.) Avoiding that 400-calorie slice of office birthday cake and a 500-calorie second helping at the family dinner once a week can translate to a full pound lost in a month.

In real-world scenarios, it is unnecessary to stop going out to dinner with friends who are overweight. But these findings suggest that mindfulness is especially important when dining out. If you focus on all of the sensory aspects of food, as opposed to mindlessly scarfing it down, you'll be able to listen to internal body cues that tell you when you've eaten enough.

For more by Rania Batayneh, MPH, click here.

For more on weight loss, click here.