Researchers next plan to test whether people can be misled to believe that they really liked certain vegetables when they were children, and whether that will make them more inclined to eat them as adults.

In the first study of its kind, published in the online version of the Proceedings of the National Academy of Science. psychologist Elizabeth Loftus and colleagues discovered that people can be led to believe they got sick as children from a specific food, such as strawberry ice cream. As a result, they became less inclined to eat strawberry ice cream as adults.

"We believe this new finding may have significant implications for dieting," said Loftus, a distinguished professor at UC Irvine.

"While we know food preferences developed in childhood continue into adulthood, this work suggests that the mere belief one had a negative experience could be sufficient to influence food choices as an adult," she added.

Establishing an Aversion

After 204 students completed questionnaires about their food preferences, they received computer-generated analyses -- some of which included false feedback indicating they had gotten sick from eating strawberry ice cream as a child.

Researchers then used two techniques to encourage the participants to process the false information, which resulted in 22 percent and 41 percent of the participants believing they had such a childhood experience. Some of them even provided details of the planted experience, such as "May have gotten sick after eating seven cups of ice cream."

Both groups showed a similar tendency to want to avoid that food now that they "remembered" getting sick from it as a child.

"People do develop aversions to foods," Loftus noted. "For example, something novel like béarnaise sauce may make someone sick once, and they can develop a real aversion to that food.

"And with alcohol, there's a medication that actually makes alcoholics sick if they drink, and the idea is to develop an aversion so that the person avoids drinking. It may be possible to do something similar with food, but without the physical experience," Loftus suggested.

Further research must be done to show whether the effects are lasting, she said, and whether people who believed the false memory actually would avoid the food if it were in front of them, as they indicated in the surveys.

Bring on the Greens

In their experiments with fattening foods, Loftus' team looked at both chocolate chip cookies and strawberry ice cream. Because participants were more likely to believe strawberry ice cream had made them ill, the researchers speculated that only novel food items are effective with the false feedback technique -- a finding consistent with research showing real taste aversions are more likely to develop with novel foods.

How recently participants believed they had eaten the food appeared to have no effect.

In their next study, Loftus and her team will look at whether people can be misled to believe that they really liked certain healthful vegetables -- like asparagus -- when they were children, and whether that will make them more inclined to eat such foods as adults.