This paper does not set out to redefine and re-explain the food security concept, but to look into the links between food security and international trade. First, we propose a conceptual framework to sum up the relationships between food security, international trade and public policies. Second, we check whether the widely used food security indicators are really suited to monitoring the impacts of government interventions and external trade shocks on the food security level. We use the Bonilla Index as our food security indicator throughout this analysis of the impact of national policies on food security.