Would a so-called Twinkie tax -- extra charges on fatty foods -- help reverse America's climbing obesity rates? Or is it more effective to reward shoppers who buy healthy goods with rebates?

A new study by Cornell researchers from the College of Agriculture and Life Sciences (CALS) and the College of Human Ecology (CHE) will seek to unravel the likely implications of legislative attempts to promote healthy eating. The research, planned to begin in early 2010, is supported by a nearly $1 million grant from the National Institutes of Health via the American Recovery and Reinvestment Act.

The seven-member team will partner with Hannaford Supermarkets, a grocery chain in parts of New England and New York state, to track how shoppers respond to rewards or penalties for their food choices.

"It's a popular idea right now to try to control obesity by doubling the price of a candy bar, for instance. But that may be unfair to consumers and also unlikely to stop someone who is really craving a candy bar," said lead researcher Brian Wansink, the John S. Dyson Professor of Marketing and director of Cornell's Food and Brand Lab. "Another view is to give rebates for healthier foods. We want to find out which is better: A carrot or a stick?"

The researchers plan to recruit 200 families for the six-month study, which will run in Utica, N.Y. Families will be segmented into four groups: those who earn a 20 percent rebate for each healthy purchase; those assessed a 20 percent tax on unhealthy foods; a set subjected to a mix of subsidies and penalties; and a control group. Each family will have at least one child at home, in order to measure the behavior of nutritional gatekeepers, the term for the person responsible for buying and preparing the bulk of a family's meals.

They chose Hannaford's because of the chain's Guiding Stars program, which rates the majority of the food on its shelves from least (zero stars) to most (three stars) nutritious.

In addition to experimenting with financial rewards and incentives, the Cornell team hopes to analyze how consumers perceive the star rating system and whether it could be a model for other stores to replicate. They will observe spending habits, but also conduct extensive interviews with families to understand their perceptions of the system.

In a related study, Cornell's team will analyze years of scanner data from before and after the launch of Hannaford's nutritional ratings. They hope to uncover what items might trigger shoppers to purchase healthy foods. For instance, Wansink said, the sale of salad dressing could be strongly linked to the sale of fresh vegetables.

"We hope to obtain a clearer picture of what products drive people to buy more fruits and vegetables," Wansink said. "Stores could use these findings to engineer healthier shopping trips, and it's also in their interest to sell more fruits and vegetables. The margin is a whole lot higher for fresh produce than Fruit Loops."

Other team members include CALS professors David Just, William Schulze and Harry Kaiser; CHE professors John Cawley, Jeffery Sobal and Elaine Wethington; and researchers Laura Smith and Jenny Lee.

The researchers expect that the grant will produce support two graduate students for two years and several part-time undergraduate data collectors.

To date, Cornell has received 126 ARRA grants, totaling more than $100.4 million.

Ted Boscia is a staff writer in the College of Agriculture and Life Sciences.