Het beoordelen van de milieu-impact van voedselkeuzes door middel van levenscyclusanalyse en consumentenonderzoek

Abstract

Reducing the environmental impact of food systems is a major sustainability challenge. Key intervention strategies include technological improvements on the supply side, as well as demand-side measures such as reducing food waste, dietary shifts, and changes in consumption habits. Life cycle assessment (LCA) is widely used to evaluate these interventions; however, when analyses extend to the consumption stage, they rarely account for the diversity of consumer practices and behaviours that shape real-world environmental outcomes. Drawing on environmental assessment, food science and technology, human nutrition, and food economics, this thesis investigates how consumption-side factors can be more rigorously integrated into the environmental evaluation of food products. This objective is addressed through four empirical studies. The first study compares the environmental impacts of consuming food products from a local initiative, characterised by mild processing, small-scale production, and local distribution chains, with those of industrial and homemade alternatives. A case study was developed for fruit juices, specifically apple and pineapple juice. The results show that combining local sourcing with mild processing can reduce environmental impacts, although outcomes remain highly sensitive to packaging choices, distribution distances, and consumer disposal practices. The findings confirm that no single characteristic, whether local sourcing, small scale, or a lower degree of processing, guarantees sustainability on its own; rather, environmental performance results from the interaction between production and supply chain characteristics, as well as consumer-related factors, particularly related with use and disposal practices. The second study examines the trade-off between packaging and food waste in a case study of fresh-cut fruits and vegetables, modelling commodity- and household-specific waste rates across household sizes. Under equivalent conditions, packaged products generally result in higher environmental impacts than their unpackaged alternatives. However, packaging can deliver net environmental benefits by substantially reducing avoidable food waste. This effect is most probable to occur in smaller households and for commodities associated with high waste rates, whereas larger households are generally expected to achieve lower impacts with unpackaged produce. The third study examines how appetite-regulating food properties, specifically satiety and satiation efficiency, can be operationalised to define functional units in food LCA. Integrating such properties has been suggested to increase functional equivalence between compared products by aligning them not only on mass but also on their ability to achieve hunger reduction and appetite regulation. Satiety and satiation were measured using an experimental approach based on ad libitum intake and post-prandial subjective ratings of hunger and desire to eat. Consequently, three functional units were defined according to the achievement of specific levels of satiety or satiation. Incorporating these appetite-based considerations into the LCA scope altered the relative environmental performance of the investigated products, reducing the differences observed in conventional mass-based comparisons. The findings provide initial evidence for the relevance of integrating appetite-regulating properties into LCA, while also highlighting important methodological limitations related to the non-linear nature of appetite responses, the substantial inter- and intra-individual variability in satiety responses, and the data-intensive and resource-demanding nature of the experimental procedures required to generate robust appetite-related inputs, which may limit the feasibility of widespread adoption implementation. The fourth study presents a discrete choice experiment (DCE) to investigate whether satiety influences food choices and whether concerns about reduced fullness represent a genuine barrier to the adoption of plant-based proteins, as often suggested. The results confirm that consumers do value satiety when choosing meals, but this preference does not differ across protein sources: consumers care equally about feeling full whether the meal is meat-based or plant-based. Resistance to plant-based options was driven primarily by attachment to meat and established dietary habits, and was not substantially reduced by providing satiety-related information. Moreover, this resistance was not uniform, with consumers showing marked heterogeneity: individuals with stronger meat attachment and more established animal-based consumption patterns exhibited greater reluctance toward plant-based alternatives, underscoring the importance of accounting for behavioural heterogeneity in dietary transition strategies. Greater prior exposure to plant-based products was associated with lower resistance, suggesting that familiarity may be more effective than informational strategies in supporting dietary transitions. Taken together, the findings demonstrate that the environmental impacts of food consumption result from interactions between production systems and consumers' diverse practices, preferences, and habits. Achieving more sustainable food systems, therefore, requires not only improvements in production and purchasing decisions, but also a broader reconsideration of the behaviours and values that shape food consumption. This thesis contributes methodological advances to food LCA by integrating consumer profiling approaches to capture behavioural heterogeneity and by incorporating appetite research into the development of alternative functional units and modelling approaches. It also provides insights into barriers to adopting plant-based foods, discusses implications for European food policy, and outlines potential actions that could support consumers in moving towards more sustainable consumption patterns.