Synergistic pathways for reducing food loss and waste along the food supply chain reconcile SDG 12.3 with distributive justice

Food loss and waste (FLW) has emerged as a critical lever for enhancing food security and sustainable development, as land degradation and declining agricultural productivity increasingly undermine the resilience of global food systems. United Nations Sustainable Development Goal 12.3 (SDG 12.3) calls for halving per capita FLW by 2030. However, global progress, national disparities and national target allocation standards remain largely unclear. Here we develop a Global FLW-FSC Nutrient Flow Dataset (G-FFNFD) and an SDG 12.3 target gap index (TGI) to systematically evaluate global progress, further quantify national inequality and design four target allocation schemes based on distributive justice. We find that the global TGI reached 113.68% in 2022, far below expectations, while revealing inequality in FLW responsibility and associated resource-environment-economic losses. Among the four target allocation schemes, the sharing responsibility scheme performs best, with simulations across 23 SDG 12.3 pathways identifying the whole FSC high FLW reduction (S4.f2) and strong synergy (S8.a2) scenarios as most effective. The FLW reductions under these two scenarios are equivalent to annual global food production increases of 10.85% and 10.89%, respectively, enabling more than half of countries to achieve or approach the SDG 12.3 target (target gap < 25%). Our results suggest that high-income countries should prioritize reducing FLW at the consumption stage through dietary guideline scenario (S2), while lower-middle-income countries focus on whole food supply chain (FSC) technological innovation (S4.f2), thereby synergistically advancing progress towards SDG 12.3.