The secret to eating less and being happy about it may have been cracked years ago—by McDonald's. According to a new study from Cornell University’s Food and Brand Lab, small non-food rewards—like the toys in Happy Meals—stimulate the same reward centers in the brain as food does.
Using MRI studies of subjects, the study found "the brain responds to a small toy, gift card, or lottery ticket in the same way it does to a mouthwatering burger or cheese-slathered pizza."
The researchers, led by Martin Reimann, carried out a series of experiments to see if people would choose a smaller meal if it was paired with a non-food item. "By combining one shorter-term desire (to eat) with another shorter-term desire (to play) that in combination also address a longer-term desire (to be healthy), different sources of happiness become commensurable."
The paper found that the majority of both kids and adults opted for a half-sized portion when combined with a prize. Both options were priced the same. The portions, as can be seen in the photographs, were literally half-sized—a hamburger cut in two, for example.
Even more interesting is that the promise of a future reward was enough to make adults opt for the smaller portion. One of the prizes used was a lottery ticket (with a $10, $50 or $100 payout), and this was as effective as a tangible gift in persuading people to eat less.
"The fact that participants were willing to substitute part of a tangible food item for the mere prospect of a relatively small monetary premium is intriguing," says Reimann. (Of course, they might have been thinking they'll just go home and eat more afterwards.)
Reimann theorizes that it is the emotional component of these intangible prizes that make them effective. In fact, vaguely-stated possibilities of winning a prized were more effective than options with hard odds included.
"One explanation for this finding is that possible premiums may be more emotionally evocative than certainty premiums," says Reimann. "The uncertainty of winning provides added attraction and desirability through emotional ‘rushes’ and ‘thrills.’ The possibility of receiving a premium also evokes a state of hope for the premium’s receipt—a state that is in itself psychologically rewarding." In other words, there's a reason people like to gamble.
The MRI results supported the survey findings. They showed that the non-food rewards lit up the same parts of the brain (the striatum) as the full-sized food portion.
How might this knowledge be used to help people eat more healthily? After all, grown-up sized Happy Meals don’t sound very healthy, even if they only contain half a Big Mac instead of a full-sized burger.
The paper suggests that the findings offer a "win-win solution for both consumers and firms." Restaurants want to sell more food, not less, while consumers shouldn't overeat. "Our research provides a simple but powerful solution to unite these two, seemingly contradictory goals of selling more versus eating less," says the paper.
One possibility is a healthy option that offers the chance to win a spa weekend, or some other prize that suits the restaurant’s clientele. Or maybe the reward of a half-sized portion could be a half-sized dessert, to be claimed only on a future date. That would get you back in the restaurant—and make you eat a little less.