There's nothing like knowing you can't eat to make a person want to eat. For many Jews, Yom Kippur means a 25-hour fast bracketed by two meals – the pre-fast seudat mafseket and the meal to break the fast. But just because you've managed to make it through those 25 hours without eating doesn't mean you should scarf down a greasy shawarma the minute you're allowed. If you do, your...