ana and nanado I don't want to things but there is a lot of evidence that smoothies are not good for you.
They contain high levels of fructose (fruit sugar) whichcontributes to dental decay
The reason why smoothies are worse than solid pieces of fruit is that the maceration process releases the fructose from the cells of the solid fruit, so that when you drink a smoothie, it's right there in your mouth, acting on your teeth, whereas if you ate an apple for instance, the fructose wouldn't be released in such large quatities until it was safely in your stomach.
Unfortunately that's not all. If you google 'fructose metabolism' you'll find all sorts of scholarly articles describing ways in which fructose affects weight gain and bloating.
I used to love smoothies when they first came out but after seeing increasing numbers of patients with quite horrific levels of tooth decay at a time of life when you wouldn't expect it, I now restrict myself to one small glass of tropicana with breakfast 