, is believed to be the first to show a decrease in food insecurity - or a lack of access to nutritional foods for at least some days or meals for members of a household - as the result of an intervention.
Mary Flynn, Ph.D., RD, LDN, the study's lead author and a research dietitian at The Miriam Hospital, designed the study with Andrew Schiff, Ph.D., the chief executive officer of Rhode Island Community Food Bank and the study's co-author. The study is based on Flynn's research of a plant-based diet she developed that emphasizes cooking with olive oil and follows a Mediterranean diet pattern.
"I had a number of people - mainly women from my breast cancer weight loss study - say how inexpensive a Mediterranean-style diet was, so I approached the food bank about designing a study using food pantry items for the recipes," says Flynn.
She points out that meat, poultry and seafood are the most expensive items in a food budget, especially the recommended lower-fat versions. Typical households of lower socioeconomic status spend grocery money first on these items, allocating far less to vegetables and fruits. However, by changing the focus to the elimination of foods not needed to improve health - such as meat, snacks, desserts and carbonated beverages - a healthy diet can be quite economical, Flynn says.
A total of 83 clients were recruited from emergency food pantries and low-income housing sites for the 34 week study. Sixty-three completed the diet protocol and the six-month follow-up requirement. As part of the study, participants attended six weeks of cooking classes, where instructors prepared quick and easy plant-based recipes that incorporated ingredients like olive oil, whole grain pasta, brown rice and fruits and vegetables. The participants were then followed for six months after the cooking program ended.
Participants were not required to assist in the preparation, but staff discussed the benefits of some of these ingredients and encouraged participants to look for these items in their own food pantry. However, no additional nutrition or food information was provided.
All cooking class participants were provided with a bag of groceries that contained most of the ingredients to make three of the provided recipes for their family members during the six weeks of the cooking classes. Grocery receipts were collected throughout the study and researchers observed significant decreases in purchases of meat, carbonated beverages, desserts and snacks, even though staff never instructed participants not to purchase these items. At the same time, there was an increase in the total number of different vegetables and fruits consumed per month.
"Not only did study participants cut their food spending by more than half, saving nearly $40 per week, we also found that the reliance on a food pantry decreased as well, from 68 percent at the start of the study to 54 percent, demonstrating a clear decline in food insecurity," Flynn says.
Following a plant-based diet also yielded some unexpected health benefits, Flynn adds. Approximately half of all participants lost weight, which was not a study objective, and there was an overall decrease in body mass index, or BMI.
"Our results also suggest that including a few plant-based meals per week is an attainable goal that will not only improve their health and diet, but also lower their food costs," Flynn says.
Flynn is also an associate professor of medicine at The Warren Alpert Medical School of Brown University.