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

Abstract

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 gu...

Consumer strategies towards a more sustainable food system: insights from Switzerland

“…We performed an environmental impact assessment of each level of the consumer strategies using the biophysical mass-flow model SOLm ( 17 , 27 , 30 ). For the 2 stages between the farm gate and the consumer, processing and transport, Ecoinvent 3 inventories were used ( Supplemental Material, Section 2 ).…”

“…When applying this principle, animals can effectively upcycle LCB, and these resources can thereby be recycled into the food system ( 19 , 29 ). Notably, grass resources in Switzerland are currently partly grown on land that could be used for the production of human food, and not all of this is temporary grassland that has an agronomic function in crop rotations ( 30 ). This needs to be considered in opportunity costs of this land use ( 11 ).…”