New York Mayor Michael Bloomberg is an interventionist who declared war on sugary soda and reintroduced calorie counts to fast food restaurants. Now, the outgoing Bloomberg administration is trying a relatively new and novel method of social engineering: Giving hospital patients “prescriptions” for fruits and vegetables, and then giving them money to buy the food at neighborhood farmers’ markets.

In a pilot program at two public hospitals in the Bronx and Manhattan, which serve primarily low-income and working-class neighborhoods, patients at risk for obesity are assigned a doctor and a nutritionist who evaluate their eating habits–and their family’s eating habits. The entire family (and not just the individual patient) is given vouchers called Health Bucks, which can be exchanged for fresh produce at farmers’ markets citywide.

The markets are typically open between one and three days a week during business hours. In press materials, the city says it views the free voucher giveaway as a “prescription” to eat more fruits and vegetables. Families are given different voucher amounts depending on their size and the ages of their children. Afterwards, nutritionists meet with families each month to check on their eating habits and encourage them to add more fresh fruits and vegetables to their dietary mix.

At a press conference, Health Commissioner Thomas Farley said “a food environment full of processed foods full of fat, sugar, and salt is contributing to obesity, diabetes, heart disease, stroke, cancer, and other chronic diseases. The Fruit and Vegetable Prescription program is a creative approach that, with the inclusion of Health Bucks, will enable at-risk patients to visit any of our 142 Farmers’ Markets and purchase the fruits and vegetables that will help them stay healthy.”

New York’s prescription program is adapted from an existing scheme called FVRx, which has been rolled out by nonprofit Wholesome Wave in other large markets like Washington, D.C., and Bridgeport, CT. FVRx claims to have decreased the BMI of 38% of child participants, and 55% of participating families reported increasing their fruit and vegetable consumption. Participants in the vegetable prescription program overwhelmingly come from low-income backgrounds: 82% are on Medicaid or a comparable form of public insurance.

The Fruit and Vegetable Prescription program isn’t the first attempt at giving the poor free Health Bucks vouchers. New York’s food stamps/EBT have baked-in vouchers for fruits and vegetables. For every $5 spent a client spends on their EBT account, they receive $2 worth of Health Bucks, stretching the potential buying power of food stamps by 40%. But the Health Bucks vouchers aren’t highly promoted, and are only used by a small portion of New York City’s poor. According to farmers’ markets operators Grow NYC, only $260,000 in Health Bucks were disbursed at farmers’ markets in 2012.

Anything that encourages better eating habits and stretches the food-buying ability of vulnerable New Yorkers is well worth championing. With that said, for the Fruit and Vegetable Prescription program to truly take off, it needs to allow patients to buy produce from non-farmers’ market vendors. New York’s farmers’ markets, typically only open during daytime hours for a short time each week, are difficult to access for the working poor. New York is a retail-dense city where most residential neighborhoods, regardless of income, rely on supermarkets, bodegas, and individual vegetable stands to purchase produce. Until those private operators also become part of the Health Bucks scheme, New York is only halfway there.