Think of a night out with your friends: You get appetizers, margaritas, a full plate of cheesy enchiladas and by this point you’ve totally blown your diet, so what’s a little fried ice cream, right? Well, that logic has a name: the “what the hell” effect. Basically, when you cross a limit you’ve set for yourself, you lose control and just go all the way.
This study put that effect to the test. Researchers served participants a slice of pizza, and though the portions were equal, some slices were cut to appear larger or smaller than the others. Later, they asked participants to taste-test cookies, and allowed them to eat as many as they wanted.
Dieters (or anyone keeping tabs on their food intake) who believed they’d eaten a larger slice of pizza consumed more cookies than everyone else—50 percent more, in fact!
The effect on mood was even more interesting. People who tend to overeat felt worse if they ate the ‘large’ slice, while people who tend to restrict their diet felt better. Maybe they’re secretly happy to be allowed a little indulgence—we know we would be!