Fasting is not just abstention from food, but primarily strict abstinence of the senses. When the senses are fed by external things, they transmit a corresponding amount of poison to the nous and the heart, which kills the poor soul’s life in God. Our Watchful Fathers have so much to tell us about the holy fasting of the senses. Their entire teaching is mainly directed at the purification of the nous from sinful fantasies and thoughts, and the purification of the heart from feelings that defile it. Furthermore, they teach that we must eradicate every evil in its beginning to keep the soul clean.
As soon as any evil thought whatsoever approaches even slightly, it is absolutely necessary that we drive it away and say the Jesus prayer right away. And when in this manner we confront the thoughts coming from the senses and the devil, very soon we will feel the joy and the profit derived from the fasting of the senses. If Eve had restrained her sense of vision, she would not have poisoned the offspring of her womb, that is, all the people who were born from her. In short, abstinence with the senses saves man from hell.
Elder Ephraim of Arizona