We conduct a field experiment with low-income shoppers to study how behavioral interventions can improve the effectiveness of healthy food subsidies. Our unique design enables us to deliver subsidies both before and during grocery shopping. We examine the effects of two non-restrictive changes to the choice environment: giving shoppers agency over the subsidy they receive and introducing a waiting period before a subsidized shopping trip to prompt deliberation about upcoming purchases. These interventions increase healthy food spending by 61% more than a healthy food subsidy alone, resulting in 199% greater healthy spending than in our unsubsidized control group.