Rebound effects in food-system life cycle assessments: insights from practitioners

Purpose Demand-side interventions, including food waste prevention, are widely promoted as means to reduce the environmental impacts of food systems. Life Cycle Assessment is central to quantifying these benefits, yet assessments often rely on substitution assumptions, while other behavioural and economic responses remain weakly addressed. This study examines how Life Cycle Assessment practitioners understand, consider, and address rebound effects in food-system assessments, using food-waste prevention as a salient example. Methods An online survey was conducted among Life Cycle Assessment practitioners working with food-system and food-waste-related assessments ( n = 79). The survey combined quantitative questions on familiarity, perceived importance, and current practice with open-ended questions capturing motivations, barriers, and reasoning. Quantitative responses were analysed descriptively, and qualitative responses were analysed thematically to identify recurring patterns and explanatory themes. Results and discussion Rebound effects were rated as moderately important but were rarely included in quantitative modelling. Practitioners did not exclude rebound effects because they were considered irrelevant, but because conditions for credible inclusion were often lacking, including data limitations, high uncertainty, limited procedural guidance, and insufficient interdisciplinary capacity. In contrast, substitution assumptions implemented via system expansion are routinely applied despite comparable uncertainty. This suggests an asymmetric treatment of substitution assumptions and rebound effects in applied food-system Life Cycle Assessment practice, where uncertainty functions as a selective gatekeeper rather than a consistent criterion for inclusion or exclusion. Conclusions The findings indicate a structural misalignment between the recognised relevance of rebound effects and their practical treatment in food-system Life Cycle Assessments. Addressing this misalignment requires clearer methodological guidance on how rebound mechanisms relate to commonly applied substitution assumptions and how uncertainty can be handled more consistently when Life Cycle Assessment is used to inform food-system policies, mitigation targets, and intervention prioritisation.