How does this apply to you? When preparing for a big training day, diversify your fuels. You can purchase or make your own sports drinks, but be sure to add other snacks too - if you can safely eat a banana while riding, you would get glucose and fructose PLUS potassium. If you'd prefer a bar, check out ones that are make with dried fruit, such as LARABAR .
Reader poll: What is your favorite snack while biking?
Currell K and A Jeukendrup. Superior endurance performance with ingestion of multiple transportable carbohydrates. Med Sci Sports Exerc. 2008(40)2;275-281.