Can people make healthier food choices without spending more money?

In a review of federal food subsidy programs, researchers found that nudging shoppers toward more healthful foods pushed cheap junk food out of the family shopping basket without adding to the government’s costs.

The data come from a study of purchases by users of the Special Supplemental Nutrition Program for Women, Infants and Children, better known as WIC, before and after changes were imposed to encourage healthy eating.

In 2009, the Department of Agriculture, which administers the WIC program, added vouchers aimed at increasing consumption of fruit, vegetables and whole grains while reducing saturated fat, cholesterol and sugar. To avoid raising overall costs, the program limited other items. The program restricted the amount of reduced-fat milk, cheese and juice recipients could buy, and eliminated whole milk from the program. If WIC users wanted to purchase foods not on the list, they had to use their own money, rather than the WIC vouchers or cards.

While many nutritionists today would not agree with all the changes, particularly the focus on lowering fat, the net effect was an overall improvement in the quality of foods and beverages the shopper purchased.

Shifting the use of the WIC funds toward more healthful foods appeared to affect the entire shopping cart, including the foods shoppers purchased with their own money. A year after the changes took effect, the amount of sugary and other unhealthful drinks purchased by beneficiaries dropped by nearly 25 percent, while purchases of foods made from whole grains and fruits and vegetables went up by about 5 percent, according to research by the Rudd Center for Food Policy and Obesity at the University of Connecticut.

“Overall, lower-income families were buying more healthful food as a result of the changes the government made,” said Tatiana Andreyeva, an associate professor at the University of Connecticut and director of economic initiatives at the Rudd Center. “There’s always so much skepticism about any government initiative, but here, not only did it work, it didn’t cost us any extra money.”

To study the program’s impact, Professor Andreyeva and Amanda Tripp of the Yale School of Public Health used point-of-sale data from an unnamed supermarket chain with more than 60 stores in New England. The supermarket has a loyalty card program that collects data on each purchase and how it is paid for.

The researchers looked at purchases made by 2,137 households in Connecticut and Massachusetts that used WIC on a regular basis to buy groceries. About half of those households also received support through the Supplemental Nutrition Assistance Program (SNAP), commonly known as food stamps.

The study compared purchases from January to September 2009, before the changes in WIC went into effect, to purchases made from January to September 2010 after the restrictions were imposed.

States administer the WIC program differently within the parameters set by the federal government, which offered an interesting example of how different tweaks result in different outcomes.

Massachusetts, for instance, only allows WIC to be used to purchase skim milk or 1 percent milk, while Connecticut also allows beneficiaries to purchase 2 percent milk under its program. The data showed that WIC households in Massachusetts had a larger increase in the amount of healthful beverages they bought after the changes than households in Connecticut did.

“Just by making slight changes, the governments were able to change the profile of what people were buying,” Professor Andreyeva said.

Nor did WIC households simply use their own money to buy foods and drinks no longer subsidized by the government, which researchers had expected. “Purchases of juice and sugary sodas went down, and people apparently just didn’t miss them,” she said.