The following letter that Catherine wrote to a religious man living in Florence makes clear the role that eating, or rather not eating, played in the lives of many women mystics of the later Middle Ages. Taken from Rudolph Bell, Holy Anorexia (Chicago: University of Chicago Press, 1985), 22-23.
In the name of Jesus Christ crucified and sweet Mary. Dearest beloved Father in Christ sweet Jesus, I Catherine, useless servant of Jesus Christ, entrust myself to you, with a desire to see us united and transformed in that sweet, eternal and pure Truth, Truth that cleanses us of every falsehood and lie. I, dearest Father, cordially thank you for the saintly zeal and jealous care that you have for my soul, because it seems to me that you are very worried, hearing about my life. I am sure you have no other motive than the desire to honor God and care for my health, fearing a demonic siege and self-deception. About this fear, Father, particularly about the matter of eating, I am not surprised; I assure you that not only you are fearful, I myself also tremble with fear of a demonic trick. But I place myself in the goodness of God; and do not trust myself, knowing that in myself I cannot trust. In response to your question whether I believed it possible to be deceived, saying that if I did not so believe, this in itself would be a demonic deception, I answer you that not only in this, which is merely a bodily function, but in this and in all my other actions, because of my frailness and the devil's cunning I am always afraid, thinking that I may be deceived; because I know and see that the devil lost beatitude but not knowledge with which knowledge, as I said, I know he could deceive me. But I turn to and lean upon the tree of the most holy cross of Christ crucified and there I wish to be nailed; and do not doubt that I will be pierced through and nailed with him for love and with deep humility, that devils will not harm me, not for my virtue but for the virtue of Christ crucified.
You wrote to me saying in particular that I should pray God that I might eat. And I say to you, my Father, and I say it to you in the sight of God, that in every possible way I could I always forced myself once or twice a day to take food; and I prayed continually and I pray to God and will pray, that he will grace me in this matter of eating so that I may live like other creatures, if this is his will, because mine is there. I say to you that many times, when I did what I could, then I looked into myself to understand my infirmity, and [the goodness of] God who by a most singular mercy allowed me to correct the vice of gluttony. It saddens me greatly that I did not correct this weakness myself for love. As to myself I do not know what other remedy to try, other than that I beg you that you beseech that highest eternal Truth to grant me the grace of allowing me to take food, if this be more for his honor and for the health of my soul, and if it pleases him. And I am certain that God's goodness will not disdain your prayers. I beg you that whatever remedy you see in this, you write to me, and as long as it is the will of God I shall take it gladly. And further I beg you that you not be too quick to judge, unless you have cleared yourself in the presence of God. I say nothing further. Remain in the holy and sweet love of God. Sweet Jesus, loving Jesus.