Rule #3: Consider using a sports drink with protein.
In most sports drinks all of the calories come from carbohydrate, but a few also contain small amounts of protein or amino acids. Studies have shown that sports drinks combining carbohydrate and protein boost performance in a more calorically efficient manner than sports drinks that provide energy through carbs alone. One study reported that a carb-protein sports drink containing 40 calories per 8 ounces enhanced endurance performance as much as a carb-only sport drink containing 50 calories per 8 ounces. So if you’re concerned about sports drink calories, you can reduce the number of calories you get from sports drinks without sacrificing performance by using one with protein.