Some recent research results: http://www.medicinenet.com/script/main/art.asp?articlekey=34000
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Very interesting. One possible drawback to the study is that the Accerlade group got extra calories from the protein (the doses were equalized by carbohydrate content), but still makes you think whether some protein is a good idea.
They also gave the beverages during and after exercise, so it’s impossible to say whether carbs+protein during and after exercise is better than carbs during and carbs+protein after exercise (the latter being a pretty common stratgey)