The Conferences of John Cassian

NAM quod semel per escarum abundantian concretus fuerit in medullis, necesse est egeri atque ab ipsa naturæ lege propelli, quæ exuberantiam cujuslibet umoris superflui velut noxiam sibi atque contrariam in semet ipsa residere non patitur ideoque rationabili semper et æquali est corpus nostrum parsimonia castigandum, ut si naturali hac necessitate commorantes in carne omnimodis carere non possumus, saltim rarius nos et non amplius quamtrina vice ista conluvione respersos totius anni cursus inveniat, quod tamen sine ullo pruritu quietus egerat sopor, non fallax imago index occultæ voluptatis eliciat.

Wherefore this is the moderate and even allowance and measure of abstinence, of which we spoke, which has the approval also of the judgment of the fathers; viz., that daily hunger should go hand in hand with our daily meals, preserving both body and soul in one and the same condition, and not allowing the mind either to faint through weariness from fasting, nor to be oppressed by over-eating, for it ends in such a sparing diet that sometimes a man neither notices nor remembers in the evening that he has broken his fast.