I blogged earlier about Christakis and Fowler’s 2007 research about obesity as a social epidemic. [See blog posts here.]
David Branchflower et al have released a paper using European Barometer data (across 29 European countries) that suggests that for Europeans as well, having fat friends may increasingly make them fat. One’s friends influences what one thinks of as fat or skinny, so having more obese friends, makes one ratchet up (subconsciously) what one thinks of as the dividing line between fat and thin.
Blanchflower and colleagues also find in German panel data that controlling for other factors, being fatter (having a higher Body Mass Index, or BMI) reduces one’s sense of subjective wellbeing (i.e., happiness). As I noted in an earlier blog, since having friends itself is associated with higher happiness and many benefits of social capital, the conclusion is not to drop one’s overweight friends, but it does suggest that if one is not mindful to ensure that you have a healthy dose of thinner friends as well, you may well find yourself fatter and less happy overall.
See also, Clive Thompson, “Is Happiness Catching?” (NYT Sunday Magazine, 9/13/09)