Is Obesity a Socially Transmitted Disease?

If you knew someone in your social circle was making specifically healthy or unhealthy food choices, would it influence your behavior?

It’s likely, say researchers in the United Kingdom who have reported on a meta-analysis of several experimental studies that all examined whether access to information about the eating habits of others influences food intake or choices.

The review, published in the Journal of the Academy of Nutrition and Dietetics (http://dx.doi.org/10.1016/j.jand.2013.11.009), looked at 15 studies from 11 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 decided what food to eat. The conclusion? Investigators found consistent evidence that social norms influence food.

The 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 the participants would make similar choices. Also, data indicated that social norms influenced the quantity of food that subjects ate. So whether your dining partner mounds a second helping of mashed potatoes on his plate—or pushes away from the table without finishing all of his food—chances are good that you will follow suit. The review also found a strong association 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,” explained lead investigator Eric Robinson, PhD, of the University of Liverpool, in a press release. “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.”

Investigators caution that more research is needed, but that these types of studies can help us understand the way people make decisions about food consumption and can help shape public policy and messaging about healthy choices.

“The evidence reviewed here is consistent with the idea that eating behaviors can be transmitted socially,” remarked Robinson. “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.”