Smoothies aren't as good as eating the whole fruit! Fruit is better than juice because it has fiber. The insoluble fiber becomes something like a mesh inside the intestine and prevents food from getting digested too soon. When you put the fruit through the blender, the insoluble fiber is ripped apart and you lose a lot of its benefit. Dr. Lustig, an endocrinologist at UCSF, talks about this in one of his lectures. It's on YouTube, but I can't remember exactly which lecture.