Cognitive Dissonance and Anorexia Nervosa: Existing Evidence

In part 1 of this post, I gave an overview of what cognitive dissonance is, common categories of strategy used to reduce the discomfort of dissonance, and some of the factors that affect which strategy is employed. In this second part, I turn to eating disorders and outline the existing evidence for their connection with cognitive dissonance.

Eating disorder-specific evidence: The Body Project

To my knowledge, the only eating disorder intervention in which cognitive dissonance plays a central role is the Body Project. Here’s a short description of its evidence base taken from their website (which also includes a list of the supporting research publications, and full program scripts):

The Body Project eating disorder prevention program reduces thin-ideal internalization, body dissatisfaction, negative mood, unhealthy dieting, and eating disorder symptoms. This intervention has also been found to reduce the risk for future onset of threshold and subthreshold eating disorders. In addition, there is evidence that the Body Project intervention reduces the risk for future onset of obesity, results in improved psychosocial functioning, and reduces mental health care utilization.

In the program, “participants verbally generate costs associated with pursuing the thin ideal in response to Socratic questions, complete role-plays in which they talk facilitators out of pursuing this ideal, write a letter to a younger self on how to avoid body image concerns, and engage in acts of body activism that challenge this ideal” (Stice et al., 2020). By inviting participants who endorse the thin body ideal to voluntarily and publicly critique it, the program is designed to generate dissonance and the resulting reduction strategy of attitude change (perhaps combined with some behaviour change, e.g. in the form of reduced dieting). (For a meta-analysis, see Dakanalis et al., 2019.)

“The Body Project is the only eating disorder prevention program to produce positive intervention effects that have been both independently replicated and significantly outperformed credible alternative interventions, making it the only eating disorder prevention program to meet the American Psychological Association’s (1995) designation as an efficacious intervention” (Horney et al., 2015). Dissonance reduction itself does seem to be a driver of the program’s efficacy since versions designed to maximize dissonance have been found to produce greater symptom reductions than those designed to minimize it, even though both had the same general intervention content (Green et al., 2005; McMillan et al. 2011). The Body Project has also produced larger reductions of thin-ideal idealization for participants with initially higher thin-ideal internalization and a threshold/subthreshold DSM-5 eating disorder at baseline, as well as greater reductions in eating disorder symptoms for participants with versus without a DSM-5 eating disorder at baseline (Müller and Stice, 2013). These findings are consistent with the thesis that those with stronger symptoms or thin ideal internalization should experience the greatest dissonance, and contradicting what might otherwise be the default assumption: that people with the strongest attitudes or symptoms would be the least likely to change.

The Project has been shown not only to reduce known eating disorder risk factors and symptoms but to reduce probabilities of actually developing a diagnosed eating disorder. In a recent study with a 4-year follow-up period (Stice et al., 2020), three variants (clinician-led, peer educator-led, and online) were tested with college women at high risk for eating disorders because of body image concerns, and over a 4-year follow-up period, eating disorder onset was significantly lower for those in peer-led groups compared to other versions and the control condition.

Completing the Body Project also offset the risk conveyed by the most potent eating disorder risk factor in one trial—denial of the costs of pursuing the thin ideal. Participants with this risk factor who completed the Body Project showed an eating disorder incidence of 0% over 3-year follow-up, versus 18% for those who completed two alternative interventions and 50% for assessment-only controls.

The Body Project has not been used as part of treatment for people with active eating disorders, although some studies like Müller and Stice (2013) above have ended up recruiting people whose diagnostic interview responses indicated a diagnosable eating disorder. As a preventative tool, however, it is demonstrably effective in ways that can be most parsimoniously explained via the concept of cognitive dissonance that provided the foundational theory. That is, it seems to work by enlisting the mechanism guiding its design.

Building on the sizeable evidence for the relevance of cognitive dissonance to eating disorders, in the next part of this post I sketch out some of the wider ways in which I think cognitive dissonance can offer an important contribution to understanding anorexia.