Being on a diet makes people more likely to feel irritable and angry, a new study has shown.
The effort involved in exerting self-control over eating can lead to an aggressive frame of my mind – and even a preference for violent films, it claimed.
In one study, people who choose an apple instead of a chocolate bar were more likely to choose movies with anger and revenge themes than milder movies.
In another study, participants who exerted financial restraint by choosing a gift certificate for groceries over one for a spa service showed more interest in looking at angry faces rather than at fearful ones.
In a third experiment, dieters had more favourable opinions toward a public policy message that used an anger-inducing appeal – if funds are not increased for police training, more criminals will escape prison – than they did toward a sad message.
Finally, participants who chose a healthy snack over a tastier less-healthy one were more irritated by a marketer's message that came across as dictatorial.
"We set out to examine whether exerting self-control can indeed lead to a wide range of angry behaviours and preferences subsequently, even in situations where such behaviours are quite subtle," said the study authors David Gal, at Northwestern University, in Chicago, and Wendy Liu at the University of California.
"Research has shown that exerting self-control makes people more likely to behave aggressively toward others and people on diets are known to be irritable and quick to anger," the authors explain.
"Public policy-makers need to be more aware of the potential negative emotions resulting from encouraging the public to exert more self control in daily choices," the authors write.
"Instead behavioural interventions might rely on a broader range of methods to foster positive behaviours toward long-term goals."
The study was published in the Journal of Consumer Research.