Are Your Friends Making You Fat?

There is an often unrecognized force that has a profound effect on your fitness and health progress: your social network. Studies have shown that our social network consisting of friends, colleagues, acquaintances, and family members influence the adoption of certain health behaviors, or lack thereof, by affecting what behaviors we view as normal.1,2 This is a concept known as social learning theory, which states that we adopt our views of what behaviors are normal by looking at the behaviors of those around us.3 As young children, the biggest social influence in our health is our parents, as they make many of the choices in terms of what we eat and how much activity we get. As we become adults, the single biggest social influence on our behavior is our peers–significant others and friends with whom we spend our time.4 This group of people has a profound effect on whether or not we will be fit and healthy or unfit and overweight. If our friends consistently make unhealthy food choices and don’t value exercise, then we are likely to follow suit.

Additionally, not only do your immediate friends influence your behavior and success, but studies have shown that your friends’ friends also influence your decisions and behaviors.5 Many of us are familiar with the concept of six degrees of separation, a phenomenon where we can be connected to anyone in the world by an average of six social relationships. Studies have shown that there is another, more powerful phenomenonthree degrees of influence. Not only does your immediate social circle influence your behaviors, but so do your friends’ friends, and even your friends’ friends’ friends. Likely, this is caused by an indirect influence on your friends behaviors, which then trickles down to you. This effect also decreases as you go further and further from your immediate group of friends, who have the biggest influence on you.

 If our behaviors are so powerfully influenced by others, how do we set ourselves up for fitness success? Don’t worry, you don’t necessarily have to go out and find new friends (unless your friends really suck). The best way to combat the negative influence of your social network is to make good behaviors visible.


The same pathway that affects what behaviors we view as normal is a two-way street, and we can influence the behaviors of our friends just as easily as they can influence ours. By making good food choices, sticking to your exercise routine, and making it known to your social network that this is important to you, you can influence them to also make better health choices. The better choices they make, the better off you are.