Trade-offs and synergies between human health and sustainability of Swiss dietary scenarios

Purpose: Aspects of human health and sustainability of diets are often analysed separately. Food systems dynamics, such as the availability of permanent grasslands, are often not accounted for in the assessment of diets based on attributional LCAs. This paper aims at an integrated analysis of diets focusing on trade-offs and synergies between healthy nutrition and sustainable food systems. Methods: We used an integrated modelling approach, linking three different models: a global mass flow model, a system dynamics model and an environmentally extended input-output model. The models were used to analyse human health, environmental, social and economic impacts and related trade-offs and synergies for a number of future scenarios of Swiss agricultural production and food consumption for three scenarios for the Swiss Food Sector in 2050. These scenarios were either developed in a participatory process during a series of interviews and group discussions with different groups of stakeholders or optimised environmental impacts while at the same time complying with different nutritional recommendations and agronomic restrictions. Results and discussion: Our results illustrate two scenarios of how healthy diets and sustainable food systems could look like. Both the SwissFoodPyramid2050 and the FeedNoFood2050 scenarios require similar dietary changes, such as a reduction of meat consumption and an increase in consumption of pulses. However, there are also some fundamental differences between the diets in the two alternative scenarios, e.g. regarding the type of meat consumed. These differences can be interpreted as trade-offs that result from agronomic boundary conditions such as the coupled production of milk and meat, the availability of natural resources, such as grassland and co-products of food processing, and health aspects of Swiss diets. Conclusions: Our results imply that there is a lack of a comprehensive food systems’ view in the current discussion on healthy and sustainable diets. Stronger coherence between human health, food and agricultural policy is needed to account for systemic boundary conditions and, thus, to allow for minimising trade-offs and maximise synergies. Current agricultural policies fail to address the health perspective. Financial support for meat and sugar producers, which lead to lower prices for those products and ultimately to a higher consumption than without these policies, are two obvious examples. Yet, comprehensive visions such as the SwissFoodPyramid scenario, the FeedNoFood Scenario or optimised scenarios would require an even more complex policy mix of incentives, regulations and information campaigns