The modeling industry is known for having overly thin models walking down its catwalks. But psychologists claim these models give young girls and women an unrealistic idea of what a healthy body should be, which can then lead to body dissatisfaction and a number of other issues. As a way to combat these stereotypes, many advertisers started using plus-size and larger-body models to promote positive body images. Results from a study published in the Journal of Public Policy & Marketing, however, suggest the influx of these images is now contributing to the obesity epidemic.

Lily Lin and Brent McFerran, assistant professors of marketing at California State University and Simon Fraser University, respectively, called this effect “The (Ironic) Dove Effect,” a reference to Dove’s #RealBeauty ad campaign, which aimed to denounce the conventional idea of beauty by showing women of all shapes and sizes in their underwear. The researchers wrote that when heavier women are used in certain campaigns it becomes “socially permissible, and individuals exhibit lower motivation to engage in healthy behaviors and consume greater portions of unhealthy food.” And they conducted several experiments to prove it. 

In a pilot study, women were asked to imagine walking past a women’s clothing store while holding two photos — one of a thin-bodied mannequin and the other of a larger one — and then rate statements, such as “I feel obese or overweight is normal,” on a scale of 1 to 7 (strongly disagree to strongly agree). Results showed women who were shown the larger mannequins felt that being obese or overweight was more socially acceptable.

In another study, women were given a cup of seven chocolates and shown three photos of plus-size women, each with their own caption — “for normal women,” “for plus-size women,” and “for women.” The researchers found those who were shown the photo that said “For normal women” ate the most chocolate. They said this effect was similar to that seen in real-life marketing, where certain taglines prompt consumers to believe larger bodies are acceptable, subsequently increasing unhealthy food consumption. A follow-up experiment in which the tag lines were removed and women were asked to create their ideal meal found those who saw these body types as acceptable were more likely to eat higher-calorie meals and be unhealthier overall.

Finally, the researchers looked at the policy aspects of plus-size women in advertising. Not only did they find acceptance of thinner models doesn’t increase motivation to live a healthier lifestyle, but that if a tax were to be implemented on unhealthy foods, those who accept larger models would strongly oppose it.

It’s become increasingly obvious over the years that thin models aren’t representative of the average woman’s body type. Plus-size modeling emerged as a response to this sentiment, and ads featuring them have steadily increased. The average waist size for women has also increased from an 8 to 16, however, giving reason for the researchers to believe plus-size models contribute to the obesity epidemic.

Obesity affects more than a third of Americans, increasing their risk of type 2 diabetes, heart disease, stroke, several cancers, and a premature death. Moreover, it’s extremely expensive to treat, costing at least $190 billions dollars annually, once all these related illnesses are accounted for.

The authors say policymakers need to be aware of advertising methods in order to manage the seemingly constant rise in obesity rates. “We conjecture from the results of several studies, including ours, that drawing attention to any body size and suggesting it is an accepted standard may be a poor idea,” Lin and McFerran wrote. “It may be optimal from the standpoint of consumer well being for marketers and policy makers to instead encourage the usage of images of people with a healthy weight, and refrain entirely from drawing attention to the body size issue.”

Lin L. McFerran B. The (Ironic) Dove Effect: Usage of Acceptance Cues for Larger Body Types Increases Unhealthy Behaviors. Journal of Public Policy & Marketing. 2015.