Het mogelijk maken van voedingsverschuivingen in de transformatie van voedselsystemen: van een efficiëntie- naar een toereikendheidsparadigma

In the triple challenge of the climate, biodiversity and justice crisis, food systems play a significant role. Indeed, they are major drivers of climate change and biodiversity loss as well as other environmental pressures. In addition, strong social inequalities in food systems leads to food insecurity and its associated burdens. To address these challenges, linked to unsustainable consumption patterns, and remain within Earth's carrying capacity, a radical transformation of our food system is necessary. In this transformation, shifting toward sustainable food consumption and production is a priority. In this context, the EAT-Lancet diet was developed by combining health and Earth's carrying capacity at the same time, allowing for cultural, context and individual preferences. Comparing the EAT-Lancet recommendations to current global consumption, it appears that high-income countries largely overconsume red meat, which is associated with great environmental impacts, while proteins from plant-based sources are neglected. Therefore, shifting towards a diet with less red meat and more legumes is often recommended to reduce one's environmental footprint. In parallel, redistributing livestock subsidies to plant-based crops is often seen as necessary for a shift towards sustainable consumption. However, environmental assessments of diets often omit market effects, taking consumption rather than production as a starting point. Moreover, the current literature on instruments for environmentally sustainable food systems does not compare to any benchmarks representing the amplitude of changes needed. Consequently, a complete analysis of on one side, the potential for environmental impact reduction from adopting the EAT-Lancet diet and on the other side, the potential from public policy instruments to reach such a diet is currently lacking. This thesis aims to fill this gap by answering the following research question: Shifting towards the EAT-Lancet diet and lowering environmental impacts: two sides of the same coin? To answer this question, we assessed, in the first part, the mitigation potential of several diet shifts and, in the second part, the potential of financial and regulatory instruments to achieve a sustainable food system. In the first part, we defined and assessed the environmental consequences of various dietary shift scenarios towards the EAT-Lancet recommendations for red meat and legumes. In Chapter 3, we evaluated a hypothetical scenario of a diet shift in the EU. For this purpose, we combined an agro-economic model, CAPRI, with a consequential life cycle assessment. In Chapter 4, we assessed three additional scenarios in the EU, the EU and China, 40% of the largest red meat eaters and the whole world, using the same methodology. The results show that the environmental benefits from individual consumption changes are limited by the structure of our global economy. Indeed, the global demand for red meat drives changes in agricultural production, which is thus only slightly affected. However, when 40% of the world's population is shifting diets, almost as many environmental benefits as when the whole world shifts diets could be obtained compared with a business-as-usual scenario. These benefits are apparent through the reduction in acidification, eutrophication, and greenhouse gasses and particulate matter emissions, particularly in countries specialised in livestock production. The associated decrease in feed production, which is greater than the increase in legume production, would decrease the impacts on freshwater ecotoxicity and eutrophication and lower the pressure on resource use. In the second part, the effectiveness of several public policy instruments to shift eating patterns and mitigate environmental impacts are evaluated. Chapter 5 focusses on financial and regulatory instruments. The current literature is analysed and reported consumption changes are compared with the EAT-Lancet diet. Similarly, reported greenhouse gas emission changes are compared with three climate benchmarks representative of what is needed for a sustainable food system. Other potential environmental impacts are estimated on the basis of reported changes in agricultural production. Among the instruments analysed, only an unthinkable consumer price change could lead to the targeted food consumption with the least trade-offs in terms of environmental impacts but with further widening social injustice. The results of this analysis show that the current instrument designs fail to achieve a sustainable diet and comfort the status quo. To conclude, the results show that shifting to a sustainable diet means shifting the current efficiency paradigm to a sufficiency paradigm. There are no one-size-fits-all solutions for this shift, and both top-down and bottom-up approaches should be considered together to mutually reinforce each other. Finally, including all sustainability aspects through transdisciplinary research as well as putting our imagination at work is essential for defining coherent context-specific solutions. This multi-approach should ensure that the path of a food systems transformation is taken.