Did you know that a 12-ounce Coke is 143 calories? Downing a can of soda each day adds 715 calories to your workweek. Stay hydrated and energized with nature's beverage instead. Keep a reusable water bottle on your desk, and take sips throughout the day. Water is not only free of calories, but it gives your belly the sensation that it's full, which cuts down on mindless snacking.