The impacts of nutrient- and health-optimal diets on the food system in Switzerland

• We use an ex-ante model to analyze the impacts of dietary shifts on the food system. • Healthy diets increase consumption of plant-based foods. • Dietary shifts increase the crop area and reduce the livestock number. • Import dependency increases with healthy diets. • Environmental impacts result in trade-offs. Current dietary choices deviate from the recommended diet and are unhealthy. Food consumption is interlinked with the food system, and improving dietary choices will have an impact on the food system. The objective of this study is to analyze the impact of nutrient- and health-optimized diets for an average Swiss consumer on the food system. We analyze three scenarios, including projected future diets and diets that optimize nutrient and health indices. We use the Swiss Sustainable Food System model, which is an ex-ante dynamic programming model. The model considers agricultural production, processing, trade, storage, and consumption stages of the food system. The results show that the projected future diet yields slightly better nutrient intake, but slightly fewer health benefits compared to current diets. Diets optimizing nutrient intake and health impacts yield substantial health benefits. Diets optimizing nutrient intake and health impacts increase the consumption of plant-based products by 55% and 78% respectively, in terms of calories, in contrast to the reference scenario, whereas they reduce the consumption of animal-based products by 35% and 43% respectively, in terms of calories. To meet the demand for these dietary shifts, agricultural production should change by increasing the area of crops producing plant-based foods and decreasing livestock numbers. Import dependency increases with diets designed to improve the health of the population. Environmental outcomes result in trade-offs, with greenhouse gas and nitrogen emissions decreasing, while water use and pesticide risks in surface water and semi-natural habitats increase.