Nearly 7,300 people enrolled in the program, far more than the 3,000 that officials had expected, Wooten said. Most (82 percent) had never been to a farmer's market before.
Among the people who enrolled, 252 took part in surveys while using the program and a year later. The percentage of those who said their diet was "healthy" or "very healthy" rose from 4 percent to 63 percent. In addition, 93 percent said the program was "important" or "very important" in their choices to shop at a farmers' market.
The cost to manage the program wasn't available, but the extra food itself cost about $330,000, an average of $93 per participant.
The study doesn't examine why the participants took part in the program. Nor does it look at whether it would be cheaper to allow the participants to buy healthier foods at supermarkets and membership superstores instead of only farmers' markets. Wooten, however, said the program is specifically designed to boost farmers' markets.
Diane Whitmore Schanzenbach, chair of the program on child, adolescent and family studies at Northwestern University's Institute for Policy Research, said it's difficult to gauge the impact of the project. She noted that many participants didn't take the follow-up surveys, and those who did may have "found the subsidy to be most valuable."
A similar federal program showed excellent results by matching 30 cents on the dollar for food stamp recipients and allowing them to spend money on produce at grocery stores, she said. "When we subsidize healthy food, low-income families purchase and eat more healthy food. It's really Economics 101."
And, she said, "it makes sense to subsidize these goods where ever people shop, be that farmers' markets, corner stores, Costco, you name it."
In the San Diego area, federal funding through the county has ended, study co-author Wooten said. But an advocacy group for refugees, whose numbers are high in poor San Diego-area neighborhoods, is continuing to support the program, she said. However, federal funding for food stamps recently dipped.
"Our hope is that Congress in the future will recognize the importance of this project and create a national program that supports this kind of effort," Wooten said.