"We did this analysis because it is commonly said that healthy diets are expensive and that it is the fruits and vegetables that make them too expensive," said Mary Flynn, Ph.D., a research dietitian at The Miriam Hospital and the lead researcher on the study. "Extra-virgin olive oil is also thought to be expensive, but we suspected it was meat that made a diet expensive, and extra-virgin olive oil is cheaper than even small amounts of meat. We expected the two diets to be similar in fruit and vegetable content, but our plant-based diet was substantially cheaper, and featured a lot more fruits and vegetables and whole grains."
In 1999, Flynn developed a plant-based olive oil diet for weight loss and to improve biomarkers for chronic diseases. An early pilot study of women with breast cancer showed that the diet resulted in better weight loss and improvement in some chronic disease risk factors compared to a lower fat diet. Participants overwhelmingly preferred it to a lower fat diet and consistently commented on how economical it was to purchase and prepare.
That effort led to collaboration between The Miriam Hospital and the Rhode Island Community Food Bank to develop a six-week cooking program research protocol aimed at improving food security -- or the ability to afford adequate food -- for food pantry clients by using plant-based olive oil diet recipes. The objective was to see whether food pantry clients would use the recipes for three dinners per week and if that would decrease their overall food costs and food insecurity. Results of this earlier study showed that participants used the recipes for an average of 2.8 meals a week and this led to a decrease in their food insecurity, total groceries expenditures, and body mass index. Seventy-six percent of those participants reported that the recipes were easier to prepare and took less time than ones they typically used.
The study published recently in the Journal of Hunger & Environmental Nutrition compared the costs over seven days of the plant-based, olive oil diet developed by Flynn to the lowest cost version of the USDA's MyPlate diet. MyPlate features a combination of fruits and vegetables that make up half the dinner plate, and requires half of all grains consumed be whole grains. Flynn's plant-based diet includes frozen and canned produce, as they have comparable nutrient content to the retail fresh version and studies show frozen and canned produce have a higher content of some of the cancer fighting components found in fresh produce. The plant-based diet also includes four tablespoons a day of olive oil, which represented nine percent or $3.61 of the weekly cost for the diet. "Extra virgin olive oil costs more than vegetable seed oil but it is unlike other oils," explained Flynn. "It is the juice of the olive fruit so it is a plant product, and numerous studies have shown olive oil provides a range of health benefits due to the components found in extra virgin olive oil."
The recent study found that including vegetables and fruits daily was inexpensive, even at fairly high amounts. Including meat was found to be much more expensive and not as healthy. Studies looking at food costs show that animal products cost more than double that of a serving of vegetables or legumes and 60 percent more than a serving of fruit; and animal products are not associated with decreasing chronic disease risk. In fact, studies have shown that frequent meat consumption has been related to increasing the risk of obesity, type 2 diabetes, heart disease, breast cancer, prostate cancer, colon cancer and overall mortality.
Research has shown that low-income households will spend their grocery money first on meats, eggs, cereals and bakery products, and that educating consumers to include some weekly meals that do not contain meat, poultry or seafood but do include extra virgin olive oil, vegetables, and a starch will decrease food costs and improve food access and body weight. "People should rethink how much meat they consume and how often," said Flynn.
Andrew Schiff, CEO, Rhode Island Community Food Bank, a researcher on the study, said, "Our goal is to provide those we serve with the most nutritious food possible and help them prepare healthy meals, understanding that the household budget is limited."
He explained, "Our findings with this study run counter to the general belief that a healthy diet must be expensive. Even using extra-virgin olive oil, a plant-based diet is far less expensive and features so many more fruits, vegetables and whole grains. This is really good news for individuals served by the Food Bank -- showing that wholesome eating on a tight budget is possible for everyone."