St. Francis de Sales on Fasting:
How many sins have entered into the soul through the eyes, as Holy Scripture indicates? [1 In. 2:16]. That is why they must fast by keeping them lowered and not permitting them to look upon frivolous and unlawful objects; the ears, by depriving them of listening to vain talk which serves only to fill the mind with worldly images; the tongue, in not speaking idle words and those which savor of the world or the things of the world. We ought also to cut off useless thoughts, as well as vain memories and superfluous appetites and desires of our will. In short, we ought to hold in check all those things which keep us from loving or tending to the Sovereign Good. In this way interior fasting accompanies exterior fasting.
This is what the Church wishes to signify during this holy time of Lent, teaching us to make our eyes, our ears and our tongue fast. For this reason she omits all harmonious chants in order to mortify the hearing; she no longer says Alleluia, and clothes herself completely in somber and dark colors. And on this first day she addresses us in these words: Remember, man, that you are dust, and to dust you shall return [Gen. 3:19], as if she meant to say: "Oh man, quit at this moment all joys and merrymaking, all joyful and pleasant reflections, and fill your memory with bitter, hard and sorrowful thoughts. In this way you will make your mind fast together with your body."
This is also what the Christians of the primitive Church taught us when, in order to spend Lent in a better way, they deprived themselves at this time of ordinary conversations with their friends, and withdrew into great solitude and places removed from communication with people.......