Joseph asked Abba Poemen the best way to fast. Poemen said, “everyone should eat a little less than he wants, every day.”

Joseph said to him, “But when you were a young man, you would sometimes fast two days in a row.”

“That’s true. Sometimes I would fast three days in a row, or an entire week. But the great hermits have tested all of these things. They discovered that it’s best to eat something every day, and then on certain days, a little less.”

By Way of the Desert: 365 Daily Readings