Even as a fox is man; as a fox which seeing a fine vineyard lusted after its grapes. But the palings were placed at narrow distances, and the fox was too bulky to creep between them. For three days he fasted, and when he had grown thin he entered into the vineyard. He feasted upon the grapes, forgetful of the morrow, of all things but his enjoyment; and lo, he had again grown stout and was unable to leave the scene of his feast. So for three days more he fasted, and when he had again grown thin, he passed through the palings and stood outside the vineyard, meagre as when he entered.
The Fox Who Fasted Twice to Feast Once
Kohelet Rabbah 5:14