Spain is likely to miss it Kyoto target in 2020 if it does not shift emphasis from labor taxes towards environmental taxes. Compared to supply-side measures, demand-side measures have proven to be more efficient in reducing GHG emissions. We assess demand-side Pigovian/CO2-eq tax on food CO2-eq reduction, welfare and diet quality in Spain based on different social costs and discount rates. Elasticities for simulations are calculated from a complete EASI demand system. Results show CO2-eq reduction are proportional to taxes. Though, taxes affect diet quality positively, it lowers household welfare indicating a trade-off between emissions goals and household´s welfare.