A man calls his mother in Israel: "Mom, how are you?"
"Not too good," says the mother. "I've been very weak."
The son says, "Why are you so weak?"
She says, "Because I haven't eaten in 38 days."
The son says, "That's terrible. Why haven't you eaten in 38 days?"
The mother answers, "Because I didn't want my mouth to be filled with food if you should call."