New research suggests obesity could be a "socially-transmitted disease."
A research team looked at a number of studies that determined how revealing the dietary habits of other influenced an individual's food intake, an Elsevier Health Sciences news release reported.
Eight of the studies reviewed in the meta-analysis looked at how "food intake norms influenced food consumed by participants; seven other studies analyzed the "effects of food choice norms on how people decide what food to eat," the news release reported.
The researchers found that if study participants knew others were making either low-calorie or high-calorie food choices it was likely they would do the same. Social norms were found to influence the amount of food eaten by the study subject as well.
The researchers also found a link between eating and social identity.
"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," lead investigator Eric Robinson, PhD, of the University of Liverpool, said. "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 researchers discovered that social norms played a role in eating habits even if the in individual was dining alone.
"Norms influence behavior by altering the extent to which an individual perceives the behavior in question to be beneficial to them. Human behavior can be guided by a perceived group norm, even when people have little or no motivation to please other people," Robinson said. "Given that in some studies the participants did not believe that their behavior was influenced by the informational eating norms, it seems that participants may not have been consciously considering the norm information when making food choices."
The researchers hope studies like this one will be taken into account in areas such as public policy.
"The evidence reviewed here is consistent with the idea that eating behaviors can be transmitted socially," Robinson said. "Taking these points into consideration, the findings of the present review may have implications for the development of more effective public health campaigns to promote 'healthy eating.' Policies or messages that normalize healthy eating habits or reduce the prevalence of beliefs that lots of people eat unhealthily may have beneficial effects on public health."
