Balancing Nutritional and Environmental Sustainability Through the Evaluation of the Water Footprint of the Recommended Italian, Spanish, and American Diets

Background/Objectives: The water footprint (WF) provides information on the impact of individual foods on water consumption, but to better direct food production toward water saving, we need to understand how to reduce the WF of our diets while keeping it healthy. In this study, we compared the WF of healthy diets based on national food-based dietary guidelines with the aim of highlighting changes in dietary patterns that could reduce water requirements without compromising nutritional adequacy. Methods: Three 2000 kcal/day dietary patterns were elaborated following the Italian, Spanish, and American dietary guidelines, and their total, green, blue, and grey WFs were calculated. Results: The Italian dietary pattern showed the lowest total WF (2806 L per capita/day), with the American and Spanish patterns being 8% and 10.5% higher, respectively. The food groups contributed differently to the total WF. In the USA, animal foods were the main contributor (56% versus 41% in Spain and 38% in Italy). The contribution of plant foods was higher in Italy (61%) than in Spain (54%) and the USA (38%). The distribution of the total WF between WFgreen, WFblue, and WFgrey was similar across the dietary patterns. Within each food group, and mainly in the animal-origin food group, the type of product significantly modulated the WF. Conclusions: Different diets can be equally nutritionally sustainable but have different impacts on environmental sustainability. The comparison of their WFs can be the starting point to promote dialogue between nutritionists, operators in the environmental sector, and the agri-food industry to ensure a healthy and balanced approach.