Joana Margarida Bôto

Abstract
The concern about sustainability is growing and the Mediterranean diet has been extensively identified as a promising model, with benefits for human and environmental health. This systematic review aims to identify and describe the indicators that have been used to evaluate the sustainability of the Mediterranean diet and the results from their application. A methodology using PRISMA guidelines was followed, and searches were performed in Web of Science, PubMed, Scopus, and GreenFile. A total of 32 studies assessing the sustainability of the Mediterranean diet were identified. Twenty-five of these studies quantified the environmental impact, 7 studies evaluated the nutritional quality, and 12 studies assessed the daily cost of this dietary pattern. A total of 33 distinct indicators were identified, of which 10 were used to assess the environmental dimension (mainly, carbon, water, and ecological footprint), 8 were used to assess the nutritional dimension (mainly Health score and Nutrient Rich Food Index), 1 was used to assess the economic dimension (dietary cost), and 8 used combined indicators. The remaining 6 indicators for the assessment of sociocultural dimension were only identified in 1 study but were not measured. The Mediterranean diet had a lower environmental impact than Western diets and showed a carbon footprint between 0.9 and 6.88 kg CO2/d per capita, a water footprint between 600 and 5280 m(3)/d per capita, and an ecological footprint between 2.8 and 53.42 m(2)/d per capita. With regard to the nutritional dimension, the Mediterranean diet had a high nutritional quality and obtained 122 points on the Health score and ranged between 12.95 and 90.6 points on the Nutrient Rich Food Index. The cost of the Mediterranean diet is similar to other diets and varied between 3.33 and 14.42euro/d per capita. These findings show that no uniformity in assessing the MDiet's sustainability exists. Statement of Significance: Although several articles have presented the Mediterranean diet (MDiet) as a sustainable diet, it is not clear how this sustainability is being assessed by different authors. This systematic literature review aims to fill this gap, by identifying and describing the indicators used to evaluate the sustainability of the MDiet, taking into account the several sustainability dimensions and looking at the results from their application.