Combined carbon and health taxes outperform single-purpose information or fiscal measures in designing sustainable food policies

This is the author accepted manuscript. The final version is available from Nature Research via the DOI in this recordData availability: The survey data collected as part of this study can be made available to interested readers upon reasonable request to the corresponding author. The Kantar FMCG data are available from Kantar Worldpanel (www.kantarworldpanel.com/en). Any other data used to design the survey are reported in the Supplementary Information. Source data are provided with this paper.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 randomised-controlled survey of 5,912 respondents from the United Kingdom (UK), we evaluate the potential impact of carbon and/or health taxes, information and combined tax and information strategies on food purchase patterns and their 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 not irrelevant, it is the imposition of taxes which exerts the most substantial effects on food purchasing decisions. Furthermore, while carbon or health taxes are best at separately targeting emissions and health challenges respectively, a combined carbon and health tax policy maximises benefits both in terms of environmental and health outcomes. We show that such a combined policy could contribute to around one third of the residual emission reductions required to achieve the UK’s 2050 net zero commitments, while discouraging the purchase of unhealthy snacks, sugary drinks and alcohol and increasing the purchase of fruit and vegetables.CUHK-Exeter Joint Centre for Environmental Sustainability and Resilience (ENSURE)Natural Environment Research Counci