How much of a person’s behavior is free will? Do people actually have a say in their health and wellness? It turns out, free will is second to what others around us are doing in regards to obesity and exercise habits.

Behavioral psychology and health studies are revealing that a person’s body weight is tied to their social network. Not Facebook or Twitter, but real-life network. In the New England Journal of Medicine, 10,000 subjects were analyzed with lifestyle questionnaires. Results showed people have a 45 percent higher chance of becoming obese if the people around them are obese. If they are friends or family, chances were even higher at 57 percent.

What is going on here? We think we possess the state of mind to make our own choices and use rationality and motivation to make decisions. This notion quickly crumbles when we go out with colleagues and a pitcher of beer and baskets of chips are on the table. Or when a compassionate friend bakes a cake to help one overcome a hard time. What others are doing quickly becomes part of us.

Adolescence is even worse. Going home to junk food, convenient foods, and takeout is only showing a growing mind that cheap and easy is the proper way to feed themselves. In college, the “Freshman 15” is about eating socially and drinking excessively because that’s what everyone is doing.

This phenomenon, however, can’t all be bad, as the opposite is also true. A person who hangs out with people in high-activity and fitness settings is more likely to participate. If we go to the trails to ride bikes, we are affirming a healthy habit with others. Many young males step into a gym, see other young men lifting weights, and become transfixed with improving their musculature and appearance. A person who begins losing weight all of a sudden has many others asking how they’re doing it, and a support system is created.

If you’re reading this, you likely have an interest in health and fitness, and it’s important to remember the lesson. Behavior is influenced by the people we are near most. Attitudes are shaped by who we are around. The health of our own bodies is influenced not by the self alone. Take this lesson and be a harbinger of health for others. Be a light of positive in a world soured by resentments. Wave and smile at your neighbor, as even the smallest influence can be a spark.