We have all heard about the perils of the obesity epidemic and its cost ho society. But something you may not know is that it’s not all about willpower and the make-up of the food environment. In this regard, Dr. Janet Tomiyama, an assistant professor at UC Los Angeles, gave a spirited, and impressively convincing, invited talk as part of Div. 38’s programming on the insidious role of weight stigma.

So how does feeling stigmatized hurt your waistline? In a recent paper, she outlines a model in which weight stigma increases one’s psychological stress, leading to increases in one’s stress physiology- in particular, levels of cortisol (that pesky stress hormone). Cortisol has many known effects, including contributing to visceral fat deposition and a drive to eat, both of which certainly undermine the goal of losing weight. Not only does weight stigma fail to motivate individuals to lose weight, it may, as Tomiyama hypothesizes, lead to additional weight gain.

Is weight stigma that prevalent? Maybe in the general population, but not among experts or clinicians who treat obese individuals, right? WRONG. In another recent study, Tomiyama examined the explicit and implicit biases against obesity among attendees of a national obesity conference. Participants (around 200 of them) completed several measures of bias, and consistent with Tomiyama’s hypothesis and prior research, even the experts showed a high level of negative bias toward obesity. In fact, compared to a similar study carried out 10 years earlier, explicit bias is actually on the rise. To follow up on this work, she turned to the laboratory and subjected participants to pictures of thin and heavier people. The participants were under the impression that they were there to judge the pleasantness of different lotions (all the lotions were actually odorless). It turns out that individuals exposed to pictures of obese people rated the odors as less pleasant than when exposed to leaner stimuli. This is disturbing, of course, but also a fine example of great social psychology.  Tomiyama described a number of other studies supporting her model, as well as several forthcoming studies.

Weight stigma reflects a novel, and often unacknowledged, contributor to the obesity epidemic. It will take further scientific creativity from Tomiyama and others to move weight stigma onto the national stage. Until then, as I told Tomiyama after her talk, “if I was still an undergraduate and had heard you talk, I would have wanted to become a social psychologist.”