Reducing food waste and reusing it as animal feed are often regarded promising solutions to enhance sustainability. Hitherto, food waste policy assessments rarely account for interdependencies between reduction and reuse interventions, and how their market - including trade - feedbacks influence sustainability outcomes. Here, we apply a global agricultural economic model to assess the impact of food system feedbacks on sustainability when EU consumer food waste is reduced or reused as pig feed. Our results show that food waste interventions easily result in sustainability tradeoffs. Halving food waste generates larger EU emission savings than its valorization as pig feed. EU savings remain below those expected when not considering market feedbacks, but additional emission savings are projected to arise abroad as consequence of shifting trade flows. When food waste is halved, decreasing food prices improve food access for consumers but reduce farmers’ income. The use of food waste as pig feed is only economically competitive if this novel feed is comparably cheap but then it stimulates pig production and imports of protein feed with potentially unsustainable consequences. Food waste reduction limits the amount of food waste biomass available for valorization. This could create unintended competition for food waste biomass. Thus, clear food waste reduction and valorization targets are needed, potentially focusing valorization on inedible waste parts only. Policy-makers need to consider such interdependencies when designing food waste interventions.

减少食物浪费并将其重新用作动物饲料通常被认为是提高可持续性的有希望的解决方案。迄今为止，食物浪费政策评估很少考虑减少和再利用干预措施之间的相互依赖关系，以及它们的市场 - 包括贸易 - 反馈如何影响可持续性结果。在这里，我们应用一个全球农业经济模型来评估当欧盟消费者的食物浪费被减少或重新用作猪饲料时，食品系统反馈对可持续性的影响。我们的结果表明，食物浪费干预很容易导致可持续性权衡。与作为猪饲料的价值相比，将食物垃圾减半产生的欧盟排放量节省更多。在不考虑市场反馈的情况下，欧盟的减排量仍低于预期，但由于贸易流量的变化，预计国外将出现额外的减排量。当食物浪费减少一半时，降低食品价格会改善消费者的食物获取，但会减少农民的收入。仅当这种新型饲料相对便宜时，将食物垃圾用作猪饲料才具有经济竞争力，但随后会刺激猪的生产和蛋白质饲料的进口，并可能产生不可持续的后果。减少食物垃圾限制了可用于增值的食物垃圾生物质的数量。这可能会对食物垃圾生物质产生意想不到的竞争。因此，需要明确的减少食物浪费和增值目标，可能只关注不可食用的废物部分的价值。政策制定者在设计食物浪费干预措施时需要考虑这种相互依赖关系。