Thaibox -- What makes you think dextrose is any different than sucrose? Maltodextrin is worse because it isn't as sweet so you need more of it. It's still 4 calories of carbs per gram.
SlapitHard -- What do you think a carb is? All carbs turn to glucose (sugar). I guess you can use a higher glycemic index, complex carb like whole wheat, but that would taste like shit in a shake.