This article studies taxation schemes which improve the sustainability of food purchases by reducing environmental emissions with focus on nutritional and socioeconomic effects. Food consumption is estimated to be responsible for 30% of greenhouse gas (GHG) emissions in Europe. Among them meats represent 8% of the French shopping basket in terms of weight, and a third in terms of CO2 emissions. For this, we estimate a EASI demand system. From environment and nutrient elasticities, we run two scenarios: an environmental friendly and a nutrient and environmental friendly. From the environmental point of view taxation of animal foods induces a moderate to strong impact on emission reductions. However the nutritional impact is far from neutral and strong favourable effects coincide with undesirable ones. Our results allow to state the terms of trade-off for nutrition with a loss of 25kg CO2 yearly.