Nasruddin was staying at the house of relatives in a distant town. He had arrived in time for dinner, but so far they hadn't served him any food at all.
The evening was dragging on as his host regaled Nasruddin with stories in which Nasruddin had no interest.
Finally, Nasruddin could not help himself: he yawned.
This prompted his host to change the topic. "You are a learned man, Nasruddin," he said. "Why is it that people yawn?"
"It's either from lack of sleep or lack of food," declared Nasruddin. "And I got a very good night's sleep last night!"
Inspired by: Mulla's Donkey and Other Friends by Mehdi Nakosteen
Notes: This story is on p. 117 of the book.