I found that my BG went sky high on smoothies, due to all the sugar content. Although, I did find that I felt full up for longer, and I also noticed the BG went down quicker too, which I am told is due to the fruit only providing a burst of glucose, and not a longer time release complex glucose release (in such things as oats).
I never tried the veg option, but I would think this is a much better idea, since you wont get such a fructose kick from all the fruit.
Test, drink, Test, Adjust!!!