Blanchflower D, Van Landeghem B & Oswald AJ (2009) Imitative Obesity and Relative Utility. Journal of the European Economic Association, 7 (2/3), pp. 528-538. https://doi.org/10.1162/JEEA.2009.7.2-3.528
If human beings care about their relative weight, a form of imitative obesity can emerge (in which people subconsciously keep up with the weight of the Joneses). Using Eurobarometer data on 29 countries, this paper provides cross-sectional evidence that overweight perceptions and dieting are influenced by a person's relative BMI, and longitudinal evidence from the German Socioeconomic Panel that well-being is influenced by relative BMI. Highly educated people see themselves as fatter -- at any given actual weight -- than those with low education. These results should be treated cautiously, and fixed-effects estimates are not always well determined, but there are grounds to take seriously the possibility of socially contagious obesity.
Journal of the European Economic Association: Volume 7, Issue 2/3