Craving sweets? Sugary treats may give you an instant energy boost, but when your blood sugar drops, you’ll feel even more tired than before. That’s because simple carbs, like a doughnut or a cookie, are metabolized faster, says Ximena Jimenez, M.D., R.D., national spokesperson for the American Dietetic Association. A better choice: complex carbohydrates, such as yogurt or a piece of fruit with a slice of cheese. If possible, combine carbs with protein; the combo will take longer to digest so you’ll have a sustained source of energy. Smart suggestions from Jimenez: whole grain toast and a slice of cheese or yogurt and ½ cup blueberries.