Perceived weight discrimination, or the real kind, may increase risk for obesity, according to survey results published by Dr. Angelina Sutin of the Department of Medical Humanities&Social Sciences, and Professor Antonio Terracciano, Department of Geriatrics researcher who focuses on how psychological traits and genetic factors contribute to physical and mental health, both from the Florida State University College of Medicine in Tallahassee.

Using people from the Health and Retirement Study, a nationally representative longitudinal survey of community-dwelling US residents, researchers compared the height and weight of 6,157 participants (58.6% female) who completed  completed their discrimination measure and had weight and height available from the 2006 and 2010 assessments.

They found that participants who experienced weight discrimination earlier were 2.5 times more likely to become obese by the follow-up assessment in 2010 - that's stereotype threat; the expectation that they would become made them more likely to become fat.  Obese participants who perceived weight discrimination in 2006 were 3 times more likely to remain obese at follow-up than those who had not experienced discrimination. 

Odds Ratios (95% Confidence Interval) for Discrimination on Obesity over Four Years.
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doi:10.1371/journal.pone.0070048 

Discrimination based on other factors, such as sex or race, did not appear to have the same correlation with weight. The stereotype threat effect of this 'weightism' was independent of demographic factors like age, gender, ethnicity or education. The researchers conclude that weight discrimination has further implications for obesity than just poorer mental health outcomes. 

Sutin adds, "In addition to the well-known emotional and economic costs, our results suggest that weight discrimination also increases risk of obesity. This could lead to a vicious cycle where individuals who are overweight and obese are more vulnerable to weight discrimination, and this discrimination may contribute to subsequent obesity and difficulties with weight management."

They also note that stereotype threat related to obesity and the perception of weight discrimination leads to poorer mental health outcomes.

Citation: Sutin AR, Terracciano A (2013) Perceived Weight Discrimination and Obesity. PLoS ONE 8(7): e70048. doi:10.1371/journal.pone.0070048