The Grapes of Wrath?

Writing in the Journal of Consumer Research, David Gal (Northwestern University) and Wendy Liu (University of California San Diego) say: "Research has shown that exerting self-control makes people more likely to behave aggressively toward others … people on diets are known to be irritable and quick to anger.”

Gal and Liu found that people who exerted self-control were more likely to prefer anger-themed movies, were more interested in looking at angry facial expressions, were more persuaded by anger-framed appeals, and expressed more irritation at a message that used controlling language to convince them to change their exercise habits. In one study, people who chose 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 chose a healthy snack over a tastier, less-healthy one were more irritated by a marketer's message that included controlling language (such as "you ought to," "need to," and "must"). Making change is stressful, but it’s worth it.