These two starving bums are walking through an alley when one of them sees a big dead rat. He runs over, sits down and starts to eat the rat, tearing the meat from its limbs. He says to the other bum, "Hey, I know you're hungry, too. Why don't you eat some of this rat?"
"Hell NO!" replies the second bum, "That rat's been dead for days, he's all stiff and cold and smelly."
The first bum says, "Okay, suit yourself," and continues to eat everything, skin, muscle, guts, all but the skeleton.
A few hours later as they are walking down the street the first bum says, "Oh, I don't feel so good. I think there might have been something wrong with that rat."
And just then, he pukes up a huge puddle of rotten rat flesh and guts with stomach bile mixed in, all half digested and looking like mush.
The second bum sits down next to the puddle and says, "Now you're talkin'! It's been months since I had a warm meal!"