Can your friends make you fat?
While there is no infectious obesity "germ" it does seem that the habits of our companions rub off on us. We don't need a randomized trial to prove this hypothesis. We've all lived it. Superbowl parties with lots of chips and dips, chicken wings and beer are communal gatherings that foster overeating. The same can be said of holidays associated with candy and chocolates. People who socialize in bars will drink more than people who meet to walk in the park. No kidding.
Experts call this "entrainment". It's a word borrowed from the science of physics where two oscillators (like pendulum clocks) fall into synchrony. Have you ever walked with someone and found yourselves walking in step with each other unconsciously? It's a fascinating phenomenon but the concept is simple: we influence each other. So use this LAW OF THE UNIVERSE to the good purpose.
Organize events around activities instead of food and include high quality real food when sharing a meal with friends. Raise the bar.
You may find that your list of friends gets a little shorter because misery loves company but sometimes less really is more: less time cooking, less money spent on expensive packaged convenience foods, less guilt about eating garbage and ultimately less weight on your body. "We should get together for a drink" can become "I walk my dog at 5:30, let's talk then." If there's a rail trail or park in your town, create an open invitation for a certain day and time of the week - maybe Saturdays at 1pm (after the farmer's market). You may be surprised to see who shows up and delighted to have good conversation while getting some much needed movement and fresh air.