Chapter 23 - What the monk's food ought to be like.
Food should be chosen not only to soothe the burning pangs of lust, still less to inflame them, but which is easy to prepare and which is readily available for a moderate price, and it should be held in common for the brothers' use. Now there are three types of gluttony: one is a compulsion to anticipate the regular time of eating; another is wanting to fill the stomach with excessive amounts of any sort of food; the third is delighting in the more delicate and rare dishes. A monk therefore must take threefold care against these: firstly he must wait for the proper time of meals; then he must not yield to overeating; thirdly he whould be happy with any sort of common food. Consuming anything unusual or out of the ordinary was considered by the ancient fathers to be tainted with vainglory and ostentation. None of those whom we admire for wisdom and discernment, or who are marked out by Christ's grace as shining examples for our imitation, are known to have refused what was then considered the most common and cheapest sort of bread. And yet those who declined to follow this rule, and spurned dry bread, searching for beans, vegetables or fruit, are never found among the most perfect monks, and failed to acquire the grace of discernment and knowledge. They do not only forbid a monk to want unusual foods, and to let his way of life become public knowledge, lest he become vain and empty-headed till he perish of conceit, but they also state that one should not lightly reveal the common routine of fasting to anyone, but should cover it up and conceal it as far as possible. When brothers visit they consider it better to show them an example of human affection than to reveal to them the discipline of self-control and daily routine. We should put before them not what we ourselves choose to desire or need, but what is needful for the travellers to rest or recover, and to do this gracefully.
St. John Cassian, The Monastic Institues, Book V