This article examines the impact of a consumption tax on environmentally unfriendly animal-based foods. It focuses on three dimensions: environmental emissions, diet quality and social equity. Using scanner data, we derive elasticities from an Exact Affine Stone Index demand system and simulate two scenarios, one including and one excluding nutritional concerns. Our results show that an environmental tax may reduce emissions (by −6.6 to −13.2 per cent based on the indicators) and improve diet quality (1.2 per cent) with a modest impact on the food-at-home budget (−4.0 per cent). This beneficial synergy between environmental and nutritional effects holds across income and age groups, with a small regressive impact.