Demand-side Interventions for Sustainable Food Systems: A Metaanalysis of Food-policy Interventions Targeting Food Consumption and Waste Behaviours

Shifting consumers towards more sustainable food consumption and avoiding food waste have been identified as key levers to mitigate climate change. Here, we use a rigorous, machine-learningassisted systematic review and meta-analysis to comparatively assess the effectiveness of demandside interventions targeting actual (or incentivised) food consumption and waste behaviours of individuals and households. Based on 209 effect sizes comprising over 4.5 million observations, we find a small overall effect size across all food-consumption interventions (z = 0.15) and a small to medium effect size for food-waste interventions (z = 0.21). When accounting for moderate publication bias, these estimates are reduced to 0.10 and 0.18. In both domains, structural choicearchitecture interventions prove equally, if not more, effective than incentives. Among these, changes in availability and defaults bring about the largest shifts in behaviour (z = 0.29-0.35). Sensitivity analysis reveals significant variability in effect sizes in the existing evidence base and underscores the necessity for future research to systematically uncover the factors determining when, how and why interventions are effective.