If it is dinner, then it depends on where I am eating. If Italian, the best rule of thumb is to go for pasta with a tomato based sauce (arabbiata is especially light). Stay away from garlic bread etc, but clear soups are always good for a starter. Biscotti are light for a dessert but if I am good for the starter and entree, I usually treat myself and have a sorbet (good) or ice cream for afters.