Two guys were swapping stories in the park one day and one guy (a war vet) mentioned that during the war he was captured and held for weeks without food.
The other guy asked, "How could you survive without food?"
"It wasn't easy," he said. "But I had a big meal before I was captured and learned to eat my own shit."
"WHAT? That's disgusting!" said the first guy. "I don't believe you!"
Without a second thought the vet reached into his pants, shit in his hand and promptly ate it on the spot.
The second guy said, "My God! If you can do that so easily, we can bet big money and rake in a fortune!"
"Sounds good to me," said the vet "I can use the money."
The next day the guy had set up a bet with two wealthy but unbelieving high rollers. "This I gotta see," said one of the gamblers.
"It ain't gonna happen," said the other. "No one can eat their own shit."
"Lets do it," said the vet's buddy as he set down a plate full of shit in front of the vet. The vet looks down ready to dig in, when all of a sudden he bolts from the table and projectile pukes a streak across the room right on the two gamblers.
In a rage the gamblers kick the living crap out of both the vet and his buddy, they take their winnings and leave.
"We lost it all!" said the buddy. "Why in the hell didn't you eat the shit?"
"There was a hair in it!" said the vet.