Researchers in the United Kingdom conducted a systematic review of several experimental studies, each of which examined whether or not providing information about other peoples' eating habits influences food intake or choices.
The review looked at a total of fifteen studies from eleven publications. Eight of the studies examined how information about food intake norms influenced food consumed by participants.
Seven other studies reported the effects of food choice norms on how people decide what food to eat.
This meta-analysis found that if participants were given information indicating that others were making low-calorie or high-calorie food choices, it significantly increased the likelihood that participants made similar choices.
Also, data indicate that social norms influence the quantity of food eaten. Additionally, the review indicated that suggesting that others eat large portions increased food intake by the participants. There was also a strong association between eating and social identity.
Lead investigator Eric Robinson, PhD, of the University of Liverpool, said that it appears that in some contexts, conforming to informational eating norms may be a way of reinforcing identity to a social group, which is in line with social identity theory.
He said that by this social identity account, if a person's sense of self is strongly guided by their identity as a member of their local community and that community is perceived to eat healthily, then that person would be hypothesized to eat healthily in order to maintain a consistent sense of social identity.
The results have been published in the Journal of the Academy of Nutrition and Dietetics.