The confrontation of literary sources and archaeological data is important to try altogether to understand the implementation of dietary prohibitions peculiar to a religion, the limits of the practice of dietary prohibitions and their evolution over time. Food prohibitions and restrictions on commensality allow different religious groups to draw a line between "them" and "us". The body of normative texts pertaining to religious and civil laws prohibiting the consumption of particular foods has often been studied for Judaism or Islam, less often for polytheisms, Zoroastrianism or Christianity. We intend to present the normative literature and to reflect on the limits of its implementation, relying on archaeozoology that can provide data on the discrepancy between norm and practice.