Fasting and penance were important elements in the spirituality of St. Francis of Assisi. Rigorous fasting allowed St. Francis to quiet all desires except for his desire for God. The Little Flowers of Saint Francis contains a story of how Francis spent an entire holy season of Lent on an island in Lake Trasimeno. The saint was inspired by God to spend Lent immersed in fasting and contemplation. Francis asked a friend who owned a small boat to take him to the island on Ash Wednesday. Francis brought with him two small loaves of bread…and nothing else.
“Since there was no dwelling in which he could take shelter, he went into some very thick brush that was formed like a little den or a little hut by many branches and saplings. And in this place he put himself in prayer and contemplation of heavenly things. And there he stayed the whole of Lent without eating or drinking, except for half of one of the loaves…[which] Saint Francis ate, out of reverence for the fast of the blessed Christ, who fasted forty days and forty nights without taking any material food. And thus, with that half a loaf he drove away from himself vainglory, and after the example of Christ he fasted for forty days and forty nights.”
-Early Documents, Volume III, page 579
For Francis, penance was an open channel to complete absorption in God. And fasting helped him curb his appetite for anything but God, so God alone could fill his heart and his entire being.