June 2014

Identifying Sustainable Foods: The Relationship between Environmental Impact, Nutritional Quality, and Prices of Foods Representative of the French Diet

Health professionals often emphasize the importance of choosing foods for your health, but something that may be overlooked is the impact our food choices have on the world’s resources and what this means for future generations.  The U.S. is one of the top five emitters of CO2 produced from agricultural activities according to the Food and Agriculture Organization of the United Nations, who have defined sustainable diets as those with low environmental impacts, which contribute to food and nutrition security and to healthy life for present and future generations.

The researchers of this study were seeking to determine which foods were compatible using sustainable diet dimensions, as they realized that no guidance is provided in official recommendations.

This study selected 391 foods that best represented the French diet and assessed the compatibility of the following sustainability dimensions: environment, nutrition, and affordability.  Environmental impact indicators included greenhouse gas emissions, air acidification, and freshwater eutrophication.  Nutritional quality was assessed taking into account protein, fiber, calcium, vitamin C, and iron.  Food prices were calculated by dividing annual expenditures by the quantities purchased.  Each food was scored on a scale of 0-3, which 3 being the most sustainable.  Most plant-based foods obtained the maximum score, while meats did not have a score above a 1.  The only foods containing animal ingredients to obtain the maximum sustainability score were milks, yogurts with no added sugar, and soups containing meat and fish. 

The results of the study showed that the three dimensions are generally compatible with each other when price was expressed per kilogram.  (They were less compatible when price was expressed per 100 kcal, as the affordability score decreased in items such as fruits and vegetables), as foods that had the greatest environmental impact had lower nutritional quality and a higher price per kilogram. Researchers suggested reducing animal product consumption as a major lever to increase the sustainability of diets. 

In order for this analysis to be used as practical official recommendations to the general public as sustainable dietary patterns, the findings have to be incorporated at the diet level with the goal of establishing culturally acceptable food combinations that are nutritious as well as environmentally friendly.  The fact that environmental impact was highly variable within food groups showed opportunity for improvement within the food supply chain.  Furthermore, regulators should address sustainability issues on both production and consumption sides of the food sector.

Masset, G., Soler, L.G., Vieux, F., & Darmon, N. (2014). Identifying sustainable foods: The relationship between environmental impact, nutritional quality, and prices of foods representative of the french diet. Journal of the Academy of Nutrition and Dietetics, 114(6). 862-869.