8 Let her not take her food with others, that is, at her parents' table; lest she see dishes she may long for. Some, I know, hold it a greater virtue to disdain a pleasure which is actually before them, but I think it a safer self-restraint to shun what must needs attract you. Once as a boy at school I met the words: 'It is ill blaming what you allow to become a habit.' Let her learn even now not to drink wine “wherein is excess.” But as, before children come to a robust age, abstinence is dangerous and trying to their tender frames, let her have baths if she require them, and let her take a little wine for her stomach's sake. Let her also be supported on a flesh diet, lest her feet fail her before they commence to run their course.
But I say this by way of concession not by way of command; because I fear to weaken her, not because I wish to teach her self-indulgence. Besides why should not a Christian virgin do wholly what others do in part? The superstitious Jews reject certain animals and products as articles of food, while among the Indians the Brahmans and among the Egyptians the Gymnosophists subsist altogether on porridge, rice, and apples. If mere glass repays so much labour, must not a pearl be worth more labour still? Paula has been born in response to a vow.
Let her life be as the lives of those who were born under the same conditions. If the grace accorded is in both cases the same, the pains bestowed ought to be so too. Let her be deaf to the sound of the organ, and not know even the uses of the pipe, the lyre, and the cithern.
Source: Letters (New Advent)