Grocery Lists Don't Guarantee Healthy Choices

WEDNESDAY, March 14, (HealthDay News) -- The grocery lists most people jot down before going to the store can create a mental loophole for impulse food.

That's because the act of remembering a variety of food choices makes people more vulnerable to slipping cookies, chips and other not-so-healthy items onto the list, a new study finds.

"The mental effort that you're using is mental effort you donothave to keep yourself in check -- controlling your desire for chocolate cake rather than fruit salad, for example," explained lead researcher Yuval Rottenstreich, an associate professor of management at Duke University.

Rottenstreich stressed, however, that it was still smarter to head to the supermarket with a list in hand than without -- just read it back and cross out any sugary or fatty items that may have snuck in.

The study is published in the March issue of theJournal of Consumer Research.

For years, nutritionists have urged dieters to draw up healthy, calorie-conscious shopping lists before they head out to the supermarket. "Not having that security of a shopping list ahead of time could actually be quite negative, especially if the person is going through the supermarket hungry," said Bonnie Taub-Dix, a New York City-based registered dietitian and spokeswoman for the American Dietetic Association.

The advice makes intuitive sense, but Rottenstreich and his co-researchers wanted to test whether it was foolproof in keeping folks true to their goals.

In three separate experiments, college students were asked to make consumer choices based on two real-life paradigms: "stimulus-based" decision-making, where the objects to choose from were right in front of the student (as would happen in a supermarket), and "memory-based" decision-making, where the students were asked to list the things they wanted to buy by drawing on their memory.

Lists didn't perform quite as well as expected.

In one experiment centered on a choice of four desserts -- chocolate cake, cheesecake, creme, and fruit salad -- the participants chose the healthier fruit salad far more when the four items were presented to them than when asked to recall the desserts from memory and then list their preference.

According to Rottenstreich, "This points out that making a list from memory does have a bit of a downside." The finding, he said, can be explained by neurology: The human brain does not have the capacity to activate both working memory and a full complement of rational impulse-control at once.

"So, if I am spending mental effort formulating my list, then that is mental effort I do not have in terms of making sensible choices," said Rottenstreich, who helped conduct the study while at New York University. In those situations, choices become more emotional, so tempting (but calorie-rich) "mistakes" can slip in.