Australian study has found warnings intended to dissuade women from over-indulging in chocolate can actually prompt increased consumption.
Published in Appetite, the work from researchers at the University of Western Australia and University of Strathclyde found low restraint eaters (non-dieters) showed a strong impulse to eat chocolate when presented with negative messaging.
This includes warnings that it could lead to obesity or phrases like 'a moment on the lips, a lifetime on the hips'.
According to lead author Prof Kevin Durkin, this surprising outcome is known as 'reactance' – when a warning has a contrary effect of releasing desire for a forbidden product.
"Reactance could be more marked among the low restraint participants because they are generally less preoccupied with regulating their food intake and thus find external attempts to intervene in freely determined behaviour more jarring," he says.
Ironically, negative messaging had no effect on 'restrained eaters', people who regularly dieted.
However, dieters did react strongly to the visual imagery in ads.
When offered chocolate in conjunction with ads featuring thin models, dieters showed increased desire to eat chocolate, greater feelings of wanting to avoid consumption, higher consumption and ultimately more guilt.
"Among participants with high restraint, those exposed to the thin model consumed significantly more chocolate, while model size didn't have any real impact on those with low restraint," Prof Durkin says.
Prof Durkin says this may be because dieters are more susceptible to a 'thin fantasy brought about by viewing ideal body images'.
A 2002 study by Mills et al found after looking at very thin models, restrained eaters reported not only that they desired to be thinner, but perceived themselves to be thinner.
"These women enjoy a self-enhancement or inspirational effect from the image. Because this results in feeling that they are closer to reaching their ideal form, they experience a reduction in the pressure to maintain their regimens," Dr Durkin says.
"From a chocolate advertiser's perspective, exploitation of young women's vulnerability to the thin ideal has some attractions."
The study involved 80 female participants between the ages of 17 and 26, categorised into low or high restraint and scored on the Orientation to Chocolate Questionnaire, developed by Prof Werner Stritzke and colleagues at UWA, and a measure of chocolate consumption.
Prof Durkin and Prof Stritzke say they undertook the study as part of a broader interest in the complex relationship between body issues, health risks associated with the highly calorific food and chocolate's status among women.
Explore further: Eating chocolate cuts risk of heart disease