It looks like it's a combination of some individual characteristics and one's social network. If for example you are more subject to influence by your network of friends then they might have greater sway over you either way...to eat less healthy or more healthy. If you are strongly directed by your values and preferences for healthy food then your social network of unhealthy eaters may have less influence. As an ER grad I was and am very committed to eating "real" food. I have found that for me, any friends who eat less healthy do not influence my choices, but eating with like minded healthy eaters certainly is a happier experience.
Al F.
