The subject I am about to address, specifically the relationship between food and religion, between nutrition and the attribution of values to eating rituals carried out by all religions, is a complex one presenting not just a few methodological problems of which it is worth analysing two in particular. The first is linked to the problem of comparison. What should one compare in the infinite landscape of these values? How should one compare the different food customs and ideologies that each tradition is obliged to develop? And, above all, with what objective, posing which questions would allow one to successfully select - within an immense mass of documentation that clearly cannot be checked by an individual specialist – all that will then allow one to observe these practices and feeding customs of specific religious traditions in a productive manner?