Gluttony, gula, is inordinate desire in eating and drinking. It is the first of the eight logismoi in Evagrius and in Cassian, and its position at the head of the monastic list is deliberate: the desert tradition held that the appetite for food is the first to be tested and the first that must be brought into order, since a monk who cannot govern it will govern nothing else. Gregory the Great analysed the vice into five modes, eating too soon, too expensively, too much, too eagerly and too fastidiously, a division Aquinas takes up in the Summa and which shows that the tradition was concerned with the manner of eating as much as with the quantity. The virtue set against it is temperance, understood as the ordering of the appetites rather than as abstinence.
Gregory the Great set out this analysis in his Moralia in Job, a vast commentary composed while he served as papal legate in Constantinople in the 580s, where he also established the influential structure that would organize the later tradition: pride as the root vice standing apart, generating seven daughter vices, including gluttony, beneath it. Later popular presentations flattened Gregory's hierarchical scheme into a simple list of seven co-equal deadly sins, a simplification that has shaped most modern retellings even though it departs from Gregory's own more structured original account.