Grocery Lists Don't Guarantee Healthy Choices

But that doesn't mean dieters should throw out their grocery lists.

"I'd say that lists do work, in lots of ways. We're just aware now that there are trade-offs," Rottenstreich said. The simple act of re-reading your grocery list and crossing out any high-fat, high-sugar items can eliminate the problem, he added.

Taub-Dix agreed that drawing up a grocery list is a great way to keep unhealthy foods out of the home. She has even come up with a means of streamlining the process that's less taxing on the memory.

"I actually have a master list that I have typed out that's more or less the layout of my supermarket," she said. "On it, I will put all my fresh fruits and vegetables listed first, then the deli, etcetera. Then I just print it out and circle what I need. It makes shopping so much easier."

Another tip: Try and stick, whenever possible, to the supermarket's outside perimeter. "That's where the fresh produce, fruits and vegetables, the dairy aisle, chicken and lean meats usually are," Taub-Dix said.

And don't ever shop when you're hungry.

"We know that when you are too hungry, it's like being too tired or too drunk," she said. "What comes from that is apathy -- 'Whatever, I'm just going to take this.' "

A separate study, published in the same issue of the journal, suggests that the human mind finds other ways to get around self-control. In some cases, suppressing one area of mental or behavioral activity spurs an excess of activity in another area, such as spending.

In the study, researchers at the University of Minnesota asked half of the participants to perform a mental task but to not think of a "white bear." Then they gave the participants $10 to spend at a bookstore. The shoppers could keep any unspent money for themselves.

The result: People who had tried to stop themselves from thinking about the "white bear" spent an average of $4.05 -- nearly three times as much ($1.21) as participants who were put under no such constraint.

The finding may have lessons for people who embark on regimens involving self-denial, the researchers said. Perhaps, they wrote, "people should avoid shopping on days when they have earlier exercised great self-control or when starting a new self-improvement program, such as a new diet."

More information

There's more on healthy eating at the American Dietetic Association.

SOURCES: Yuval Rottenstreich, Ph.D., associate professor, management, Fuqua School of Business, Duke University, Durham, N.C.; Bonnie Taub-Dix, M.A., R.D., dietitian, New York City, and spokeswoman, American Dietetic Association; March 2007,Journal of Consumer Research