This article analyses the current state of the debate over competition for land use, by means of an index of the main arguments in favor and against the production of liquid biofuels and the impacts on food production. Based on this index, an analytic framework is constructed to establish the causal relations indicated by the existing studies on this competition. We find that the emergence of agro-energy has altered the land use dynamic, albeit not yet significantly, with a shift of areas traditionally used to grow foods over to crops to produce biofuels. This has been contributing to raise food prices in the short run. However, it is probable that this is not the only factor determining this trend, nor will it last over the long run. The challenge is to conciliate the production of biofuels with the production of foods in sustainable form.