Planning is the key to sticking to the holiday diet. Avoid the traps and perils of a well-stocked break room, or a kitchen cabinet filled with goodies. Plan on eating three meals a day plus one naughty treat. Yes! Have that yummy iced Christmas cookie. Go ahead, swig a spiked egg nog at the holiday party. You can even enjoy Auntie's sweet potatoe casserole, without guilt, when you plan ahead.