Balancing animal-source food intake between nutritional requirements and sustainability impacts

Summary

The current environmental, social, and economic challenges of food systems necessitate actions towards more sustainable consumption patterns and production approaches. Reducing animalsource food (ASF) intake is a promising strategy to solve multiple sustainability issues. However, how many and which animals could be part of a sustainable food system remains up for discussion, as well as how the remaining ASF should best be produced. This thesis aimed to investigate the role of ASF in current and potential future food systems, with special emphasis on integrating different sustainability impacts. We conducted a literature review to understand why certain ASF are proposed as solutions for more sustainable diets. There, we found that studies considering statusquo impact assessments and specifying consumption-oriented scenarios recommend to reduce beef and pork rather than chicken. In these studies, the role of ASF is mostly limited to current production practices and feed food competition is not addressed. Studies considering systemic consequences and specifying resource-oriented scenarios propose larger reductions of chicken and pork, because these are produced with more food-competing feed. In these latter studies, the role of animals and the resulting ASF is mostly limited to converting low-opportunity-cost biomass, thereby avoiding feed-food competition. In future research and communication of more sustainable dietary solutions, these choices and the resulting consequences should be considered to enable effective communication and policy design. Further, we assessed environmental and socio economic impacts of current dietary choices in Switzerland, and related these to different sociodemographic and lifestyle factors. Our results showed that while nationalities, language regions, age groups, and smoking status seemed particularly distinctive, income or educational groups seemed hardly relevant. Food choices and the resulting sustainability impacts thus markedly differed between these factors, suggesting that these can be relevant, for example, to target nutrition campaigns. Then, we assessed environmental and socio-economic impacts of different consumer strategies for Switzerland, including dietary changes as well as production-side changes. While the dietary changes towards more plant-based diets improved the environmental performance, diet quality, and diet cost, these changes increased social risks. Moreover, increased share of organic agriculture had ambivalent effects on the environmental performance. When enhanced with circularity principles, however, all environmental indicators improved substantially. Consequently, we assessed the nutritional and environmental consequences of integrating animal-source food recommendations with circularity principles, both in national dietary guidelines (Bulgaria, Malta, Netherlands, Sweden, and Switzerland) and for the EAT-Lancet dietary guidelines. While for the latter, ASF protein of the recommendations could be met, we found this not to be feasible for the national guidelines assessed. Nevertheless, considering circularity aspects in dietary guidelines by linking the types of ASF to available low-opportunity-cost biomass offers large potential to improve the resource use efficiency in food systems, and simultaneously improving environmental performance. In conclusion, the role of ASF in more sustainable food systems can be manifold – and depends largely on the required nutritional contributions as well as on defined priorities for different dimensions of sustainability. Importantly, to thoroughly assess the role and potential of ASF for improved sustainability, adequate methods need to be used and adopting a systems-level analysis going beyond product-specific efficiency measures is unavoidable.