But what determines how much we eat? It can’t be just because we are hungry, since almost everyone overeats sometimes. We get cues from our environment.
The good news is that we can control one of these cues, which gives us a simple way to guide ourselves to eating less. For a long time some dieters have assumed that this cue works. Now we have the scientific proof that it does.
The size of the bowls that we eat out of and the size of the spoons that we use to serve ourselves matters. Most of us can use smaller bowls and spoons to help ourselves better control how much we eat. On the other hand, people who need to put on weight can use bigger bowls and spoons.
It’s just an illusion. But even when we know that it is an illusion it can help us. After learning about this research, I have shifted from serving myself in big bowls to small bowls and on dinner plates to salad plates. And now I always use teaspoons rather than tablespoons or soup spoons. These are now two of the strategies that I use to keep my weight moving down.
It’s been about a century since two psychologists – a German named Hermann Ebbinghaus and an Englishman named Edward Bradford Titchener – discovered the size-contrast illusion. Recently, this illusion suggested to Brian Wansink and his colleagues that it might leads people to over-serve themselves depending on the size of the bowls and spoons that they used.
Dr. Wansink kindly sent me a pre-print of their study, “Ice Cream Illusions: Bowls, Spoons, and Self-Served Portion Sizes.” The American Journal of Preventative Medicine is scheduled to publish it in the September 2006 issue.
The size-contrast illusion does lead us to eat more when our bowls and spoons are big. Of all people, nutritionists were the guinea pigs in the new research. Dr. Wansink and his colleagues invited 85 nutrition experts to an ice cream social and randomly gave them either a smaller or a larger bowl that was twice as big. The nutritionists then took the amount of ice cream that they wanted.
Even these nutritionists were fooled. Those experts who got a larger bowl served themselves and ate 31 percent more ice cream than those who got a smaller bowl. And they didn’t think that they had eaten more than the others did.
Then, Dr. Wansink and his colleagues increased the size of the spoon 50 percent from 2 to 3 oz. The nutrition experts ate about 15 percent more ice cream than those who used the 2-oz spoons. This was irrespective of the size of the bowl.
How much we put in our bowls and in our spoons is important. We generally eat almost all the food that we serve ourselves. Dr. Wansick estimates that we eat 92 percent of the food we serve ourselves based on one of his earlier studies. He is professor of marketing at Cornell University and director of the Cornell Food and Brand Lab.
It’s easy to use smaller bowls and spoons at home to give any weight-loss program a kick. I use smaller plates too. But when we go out to eat the restaurants usually give us big portions on big plates.
The key here is for us to pick our restaurants with serving size in mind. I still remember eating years ago at the classy Theo’s Restaurant in Soquel, near Santa Cruz, California. They served us delectable portions, but they were small portions on really large plates. Maybe that’s why I left feeling hungry.
More recently, I noticed a nice change at Souplantation and Sweet Tomatoes, a large chain of salad buffet restaurants. Their serving plates for salads are smaller than they used to be. That’s good for the restaurant, because we don’t eat as much, so they make more money. It’s even better for us because it removes a cue to eat more.