Some diseases are better treated by a change in diet than by a pill. But nutritional advice is impossible to follow when a patient is too poor to know where the next meal is coming from or lives in a place without easy access to fresh fruits and vegetables. Many patients may not know, moreover, how to prepare the right foods to get their chronic diseases under control.

So hospitalist Rita Nguyen and the San Francisco Health Network, the comprehensive system of health care services in San Francisco County, launched “food pharmacies” at several primary care clinics.

The project is a recent entrant in the growing food-as-medicine movement, based on the idea that hospitals and other health care providers can take a more active role in promoting diets that can help in patient treatment. At several clinics throughout San Francisco, low-income patients who have hypertension or diabetes can fill their “prescriptions” and receive a few months’ worth of healthy groceries for themselves and their families at no cost. The program also provides basic cooking tools—olive oil, spices, steaming kits—and cooking lessons, in the hope of inspiring lifelong change.

Q: Why should health care systems get involved in providing food?

A: Even with our existing food safety net, many people can’t meet their nutritional needs. And we know that when people aren’t getting enough food or the right types of food, they are more likely to have hypertension, high cholesterol and diabetes.

Food programs like this one acknowledge that healthy eating is at the core of a patient’s medical care. We aren’t having a diabetes epidemic or obesity epidemic because we’re not giving people enough medication. To control these conditions, we need to address the underlying problem: that patients don’t have the tools and access to eat the right foods.

Q: Are there other programs like yours?

A: The Preventive Food Pantry at Boston Medical Center has been around for many years, and it now serves more than 6,000 patients and their families a month. There are a handful of other food pharmacies as well. But we’ve taken a slightly different approach. We’re at several primary care locations, for one, which is more convenient for the patient.

But, really, the medical message around food is about restrictions—these are all the foods you can’t eat. We want to flip that around and focus on the joy of good nutrition. We teach patients skills, such as how to blanch and freeze vegetables, or how to prepare healthy food in a microwave if they lack a stove. We give them tastes of foods they might otherwise never try, like tofu. We’re also building a supportive community; patients discuss what they’re cooking with one another, and they’re very proud to share their recipes with the group.

Q: Are you seeing positive changes?

A: We have preliminary data on the patients with diabetes and hypertension who went through our three-month pilot program. About half the patients said they were eating healthier. Half reported they had improved their blood sugar and about 40% said they had lowered their blood pressure. When we looked at their medical records, there was a trend toward improved blood sugar as well, but this was a very small pilot so we aren’t quite ready to make strong conclusions.

We’re also conducting a randomized trial with patients who have been hospitalized for heart failure. Right now, nearly one out of three patients with heart failure at our hospital is readmitted within 30 days, and we are assessed a financial penalty for those readmissions.

So we’re giving some of these patients five months of free meals and groceries—the means to adhere to a diet designed to control their disease.

Q: How can several months of free food tackle patients’ food insecurity?

A: It can’t. Reducing food insecurity and supporting healthy eating require everyone doing their part—nonprofits, school districts offering healthier school meals, policy changes such as soda taxes.

But having a health system support this work sends an important message. Food insecurity is a health issue, not merely a moral issue. It should be standard practice, for instance, to ask patients if they ever worry about where the next meal will come from. And if we can demonstrate that we can actually save money by giving patients a leg up on healthier diets, then we can make the case for more programs like this.