Jewish World Review Feb. 20, 2003 / 18 Adar I, 5763

SLIM CHANCES: Are visual cues undermining your diet?

By Bev Bennett | As a child, you may have been admonished to not waste food. "Don't put too much on your plate,'' went the parental line. "Your eyes are bigger than your stomach.''

Unfortunately, if you're watching your weight, that's not always the case. People adjust to whatever portion of food they are offered; they may not even notice that portions have become larger. As more people dine out, and as super-sized restaurant servings become the norm, it's becoming more difficult for people to push themselves away from a half-filled plate.

"The interesting thing about food intake and satiety is that it's negotiable,'' says Barbara Rolls, Ph.D, a professor nutrition at Penn State in University Park. "People have signals for satiety, but in situations that showcase tasty food, or in social food situations, people can override the signals.''

Rolls and her colleagues recently conducted an experiment to show how people are influenced by the presence of large amounts of food. A group of 51 men and women who were either of normal weight or overweight were fed a lunch of macaroni and cheese once a week for four weeks. Each time, the volunteers were offered a different amount, from a low of 500 grams -- which is more than a pound---to a high of 1,000 grams.

The volunteers were divided into two groups. One group was given a plate with a specific amount of macaroni and cheese. The second was given a serving bowl with different amounts of food on different weeks. Those people could help themselves to as much macaroni and cheese as they wanted.

"We thought that when people could decide what to put on their plates, they wouldn't decide to eat more,'' says Rolls, author of the weight-loss book "Volumetrics'' (Harper Torch, 2003 soft cover).

That didn't turn out to be the case. Both groups ate more as more food was presented. "One of the intriguing things was that the volunteers didn't end up hungrier or fuller. These people on the whole seemed reasonably unaware that they ate more,'' says Rolls, who asked the volunteers what they thought was the purpose of the study.

Her research supports earlier work done by her colleague Leann Birch at Penn State. In Birch's experiments, children ages 3 and 5 were given various servings of macaroni and cheese. The younger children stopped eating when they were full, before their plates were clean. The older children were influenced by visual cues and ate more food as it was given.

Rolls says her lab experience, and that of her colleague, might show why it is so hard for people to eat sensibly when restaurants and the food industry promote large servings. "To expect consumers to be smart about what to eat isn't going to happen. Portion sizes are so confusing anyway,'' says Rolls.

However, it isn't realistic to expect Americans to cut back and eat a nutritionally approved portion size, Rolls says. "Telling people to eat less isn't a useful message. It should be eat less of some things but more of other things. It's not just portion size; it's big portions of highly caloric food. People should be encouraged to eat big portions of salads without high-fat dressings.''

Bev Bennett is co-author of "The Dictionary of Healthful Food Terms.'' Comment by clicking here.


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