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So, is banning supersized cups a good way to get people to drink less soda? Well, that's the question we'll put to Brian Wansink who has studied portion size and how it affects consumption. He is professor of consumer behavior at Cornell University in Ithaca, New York.

Professor Wansink, welcome to the program.

BRIAN WANSINK: Well, it's great to be with you.

BLOCK: And you've called us a nation of mindless eaters.


BLOCK: Why don't you tell us what that means for how the size of the container or a portion affects how much we consume?

WANSINK: Well, absolutely. What we found out in the research that we have done up here in Cornell is that the typical person makes over 200 decisions about food a day. Most would think we make about 20 or 25. But we're going to be just a nation of mindless eaters, because we're not aware of all the things around us, all the cues around us that trick us in eating or drinking a little bit more than we otherwise would; whether it be the, you know size of a bowl or cup. Or whether it would be what the person is doing next to us, or the music that's in a room or the lighting.

BLOCK: And in terms of a size of a container, if I'm handed a 32-ounce soda, won't at some point my body say I'm done with soda. I'm not going to finish this. I'm going to drink half of it?


WANSINK: Well, we like to think so. But, I mean, our eyes are a lot bigger than our stomachs. We eat with our eyes and not with our stomach. And so, our stomach is fairly crude when it comes to telling us whether we're full or not. So what we actually do is we eat or drink a certain amount that looks appropriate on a plate or in a cup.

BLOCK: Now, you did a study about how much popcorn people would eat during a movie.


BLOCK: And you found that even if the popcorn was terrible, really stale and nasty, people with a big container ate more of it. I think I know this feeling.


BLOCK: I think I'm a case study in this.

WANSINK: Well, yeah. We did a study in Chicago. We gave people either those, you know, those large size popcorn containers or the super large-size ones. But this is five-day old popcorn that had been in entomology lab...



WANSINK: ...for five years - it was like eating Styrofoam. What we found is that even though we looked at people who had just eaten dinner, we gave them terrible popcorn. A typical person still ate about 33 percent more popcorn if they were given a bigger container. But if you ask them if the bigger container influence them, they go: No, no, no, it couldn't have.

BLOCK: I have seen this argument about soda in particular, that regardless of portion size, it doesn't make us feel full. So, no matter how much we're given, we'll just keep drinking it. We don't reach a sense of fullness.

WANSINK: Well, it's truth of all beverages. They just really don't have the same either mouth feel or that (unintelligible) feel that, you know, an equal amount of fiber would, for instance.

BLOCK: Well, what are your thoughts on New York Mayor Bloomberg's plan here? He wants to restrict supersized drinks as a way to fight obesity. Think it's a good idea?

WANSINK: I really think it's not going to have really any dent. Or if it does, it's only going to be a small one. Because the people who love this stuff will continue to love it. They're going to think of ways to get their fix.

But my bigger fear is that if this fails, it's going to be an epic failure in the fight against obesity. Because all of a sudden, it's something that's very visible and, you know, it's supposed to work theoretically. If it fails, what's the next step than maybe throwing up your hands and saying, oh, let's look at something else.

BLOCK: And that's the wrong message, you think?

WANSINK: I think so too. I think this could be done in a lot better way by engaging these retailers and figuring out what can be done to kind of reduce the stuff by still making it profitable for you guys.

BLOCK: How would you engage retailers to get the same effect in the end?

WANSINK: Well, in the same way when we engaged manufacturers about 15 years ago, in talking to them and saying, look, you could charge a premium for offering less and getting people to eat less and then pay more. They go, oh, yeah, OK. And they thought of a number of different ways to make that happen in ways to promote it, to package it differently.

BLOCK: Brian Wansink, thanks for talking with us today.

WANSINK: Thanks very much.

BLOCK: Brian Wansink directs the Food and Brand Lab at Cornell University. He's author of the book "Mindless Eating: Why We Eat More Than We Think."

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