Hmm.  I wonder if whey powder is a good substitute for the tofu.  I don't remember a smoothy with tofu, but I'm guessing that the tofu is in the recipe for protein as well as thickening.   I was told that adding the banana does add more sugar to the eye opener smoothy, so when I actually get on the whole diet (I've really been just flirting with it), I have to be careful about taking fruit from the snack portions of the menu, rather than just adding to it.  Oh, I also tried adding both banana and strawberry one day, and that was great, too.