Joke Type: bait and switch

Considering the problem, the doctor said, “There is one thing we can try. It’s an experimental diet in which the jaw is wired shut and nourishment is provided through the rectum. Since the rectal walls can only absorb small amounts of food at a time, you will lose weight quickly.”

LaJoie agreed to try the diet. Three weeks later, he returned for his checkup and, much to the doctor’s delight, the formerly obese man was now quite slender. He also had a remarkable bounce to his step.

The physician removed the wire from LaJoie’s jaw and the man sat down. Much to the doctor’s surprise, his patient continued to bounce up and down on the seat.

“So how do you feel?” the doctor asked.

“Marvelous! Never better.”

“Then tell me, why are you bouncing up and down like that?”

“Oh,” says LaJoie, “I’m just chewing some gum.”