I get great energy and prevent muscle breakdown using a little cocktail of 8 oz gatorade, some crushed ice, water, 2 scoops vanilla whey, some bcaa's, plus/minues creatine. Might want to give it a try, but dont go overboard on the simple carbs.
Also can add 5-10 g glutamine as well. Just make sure you have plenty of liquid in the shake. Last thing you want is to have to stop your workout for a bout of osmotic diarrhea