The food system is a major source of both environmental and health challenges. Yet, the extent to which policy-induced changes in the patterns of food demand address these challenges remains poorly understood. Using a survey-based, randomized controlled experiment with 5,912 respondents from the United Kingdom, we evaluate the potential effect of carbon and/or health taxes, information and combined tax and information strategies on food purchase patterns and the resulting impact on greenhouse gas emissions and dietary health. Our results show that while information on the carbon and/or health characteristics of food is relevant, the imposition of taxes exerts the most substantial effects on food purchasing decisions. Furthermore, while carbon or health taxes are best at separately targeting emissions or dietary health challenges, respectively, a combined carbon and health tax policy maximizes benefits in terms of both environmental and health outcomes. We show that such a combined policy could contribute to around one third of the reductions in residual emissions required to achieve the United Kingdom’s 2050 net-zero commitments, while discouraging the purchase of especially unhealthy snacks, sugary drinks and alcohol and increasing the purchase of fruit and vegetables.

粮食系统是环境和健康挑战的主要根源。然而，政策引发的粮食需求模式变化在多大程度上应对这些挑战仍知之甚少。通过对来自英国的 5,912 名受访者进行基于调查的随机对照实验，我们评估了碳税和/或健康税、信息以及综合税收和信息策略对食品购买模式的潜在影响，以及由此对温室气体排放和饮食健康。我们的结果表明，虽然有关食品的碳和/或健康特征的信息是相关的，但征税对食品购买决策产生最重大的影响。此外，虽然碳税或健康税最适合分别针对排放或饮食健康挑战，但碳税和健康税相结合的政策可以在环境和健康结果方面实现效益最大化。我们表明，这样的综合政策可以有助于实现英国 2050 年净零排放承诺所需的残余排放量减少约三分之一，同时阻止购买特别不健康的零食、含糖饮料和酒精并增加水果的购买和蔬菜。