Fitness & Nutrition


U.S. troops aren't the only ones struggling with their diets. Here's a challenge to think about: You're in a fast-food restaurant and you're informed that the hamburger you're about to order has 900 calories. What do you do? Do you still buy it? You say you'd order something less caloric?

Well, we asked behavioral economist Dan Ariely.

Professor DAN ARIELY (Psychology and Behavioral Economics, Duke University): So you would expect so, right? You would expect that the moment you give people information and you tell them how much the calories something is, people would stop consuming high-caloric stuff. But the reality is that the evidence is just not there.

In New York City, when they passed the legislation that fast-food places have to post calorie information, and they looked at what effect it has on fast-food consumption, they saw no effect. In one study, it actually went the other way around. People said, hey, only 800 calories. I can say, give me fries with that.

(Soundbite of laughter)

Prof. ARIELY: And we have done this study at Duke. We went to a fast-food Chinese place called Panda Express.

SIEGEL: Mm-hmm.

Prof. ARIELY: And the CEO came to my class at some point and he said, you know, why do people eat all these bad stuff? Panda Express has better food from caloric perspective and lots of people eat the orange chicken, very high in calories.

SIEGEL: This, by the way, mystifies people in China, how it became known as Chinese food.

(Soundbite of laughter)


Prof. ARIELY: And he was saying, you know, how can we get people to consume stuff that is better for them? So in the Duke version of Panda Express, we did a calorie labeling experiment. We posted caloric information out there and we saw absolutely no difference.

SIEGEL: Even if you told people the chicken is much more high-caloric...

Prof. ARIELY: Yeah, people don't change. But then we said, what else could we do? What other interventions could we do? And one of the things we tried was, well, we said, what if we ask people would you take less of an amount of this orange chicken?

SIEGEL: Mm-hmm.

Prof. ARIELY: And people said no. Then we said, what if we took - gave people an option to get less of an amount of the side dish? What if we said, hey, what about if we gave you half a portion of fries, that would save you 250 calories? Are you interested in that? And more than 40 percent of the people said yes, I'm interested in that.

SIEGEL: Really?

Prof. ARIELY: Yeah. And what happened in eating is that no matter how much people give you to eat, you eat the whole thing, right? So it's really a question of how much are you going to start with. Because we've also tested this, we looked at what people end up with and how much they throw away and so on. People eat everything you give them.

SIEGEL: Mm-hmm.

Prof. ARIELY: But if you give people a mechanism to limit what they're going to have for food later on, people actually eat less as a consequence.

SIEGEL: And you think the offer of a smaller portion of rice somehow clicks with people because it's taking the secondary substance, reducing not the main event here, but the...

Prof. ARIELY: That's right. The secondary event, it cuts calories and would let people execute something that is good for them.

I do have to say that we also stopped this promotion and we looked at what happened the next day. Would people keep on asking for that thing? Hey, I was here yesterday, they offered me a half a portion of fries, can I do it again? Nobody does that.

(Soundbite of laughter)

Prof. ARIELY: So when you offer people, they understand it's a good offer and they cut down on the calorie. But when you don't offer it to people, they're not doing those in their own self.

So we have to think about not just what information we give to people, but how we get them to think about different paths of saving caloric consumption.

SIEGEL: The late Tip O'Neill, speaker of the House in Congress, used to say one of his rules of politics was people liked to be asked.

Prof. ARIELY: Yeah, I think it's right.

SIEGEL: Dan Ariely, thank you very much.

Prof. ARIELY: My pleasure.

SIEGEL: Dan Ariely, professor of psychology and behavioral economics at Duke University, and author of "The Upside of Irrationality," talked with us about irrational behavior here on ALL THINGS CONSIDERED.

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