Friends can be your worst enemy when it comes to trying to keep control of your waistline. Even if they aren’t overtly using peer pressure to coax you into eating unhealthily, they can be doing so through their own actions.

Most of us know them: people who can eat and eat and not gain an ounce. That fraternity gets a little smaller after 30 when everyone’s metabolism begins to slow. But, while they still maintain this seemingly impossible dietary feat, they do so at the expense of the rest of us.

That’s because according to a new study in the Journal of Consumer Research, thin friends who eat a lot may unwittingly make you eat more in the process. Call it subliminal peer pressure.

Time magazine recently published an article, reviewing research discussed in the American Journal of Clinical Nutrition on how the eating habits of teens and tweens are influenced by how much their friends weigh. Observing the participants in this study, the researchers found that the children ate more when they were with a friend than when they were with a peer they did not know; however, they also found that children who were overweight ate up to 300 calories more when with a friend who is also overweight.

More lessons from 10,000 feet… On this flight, I am sitting near Russ who travels frequently for business. While distracting Emily from her flight anxiety, Russ told her and I about a flight he experienced during which the oxygen masks fell. He shared that all the passengers automatically turned their heads right and left like the flight attendant does during her pre-flight spiel. He and I both found it interesting how such things can be ingrained into our consciousness. I would venture that few to none of the passengers had ever had to utilize an in-flight oxygen mask prior to that incident.

Unless your flight anxiety is high, my guess is that you tune out the spiel after your first flight or two (even Emily didn’t seem to be paying much attention); I know I don’t consciously pay attention and didn’t realize how the flight attendants turn their heads. Yet, almost everyone mimicked the flight attendant automatically.

During session the other day, a client stated that one of the reasons he/she first started counseling was because if you do not do anything differently then nothing will ever change. I am always proud when a client owns such a statement and even more so in this case because I believe this client has never heard that from me, even if it is a foundational belief that I share. I am certainly not the only change professional that holds to this idea and you have probably heard variations of the same theme from several sources. I recently read about an extreme use of this idea in the book When You Are Engulfed by Flames by David Sedaris. David writes that when he wanted to quit smoking, he needed to shake up his schedule and break his routine, so he moved to Japan for a while.

Recently the question has been posed to me in various variations of ‘how do we reach the teens’? As a therapist and working closely with INShape Indiana on health promotions, I understand that you cannot work harder for someone than they work for themselves, or you cannot care about their growth more than they do. Doing so would be a fast track to burnout and poor client relationships, which helps no one. I have taken to regularly texting and chatting with a few of my teen cousins to try to make sure I understand their culture and what is motivating to them. (We didn’t have texting when I was a teen!) If we find it difficult to motivate real life change in adults who generally have a wider perspective on the real costs and benefits, how do we reach teenagers and help them develop healthy habits early?