Have you noticed that a number of fast food restaurants including both McDonalds and Burger King have decided to sell smoothies? I was a bit surprised by it knowing the origins of this kind of drink and the fact those two fast food joints, as currently defined, are not going to make you anything that resembles a traditional smoothie. First of all, traditional smoothies are not what I would call inexpensive for the restaurants to provide (at least when you compare them to the other beverages for sale at these establishments). Secondly, they take a bit longer to make than the time it takes to simply dispense a a non solid such as soda and soft ice cream. While I am sure there would be a way to scale the process of making them, I don't see it happening in the near term.
If you are curious about traditional smoothies, I recommend you look at recipes that are online. There are a lot. I've been working on and perfecting a smoothie that is both very nutricious and delicious. Here's more info and the recipe. See what you think!
Cals- 335, Carbs 52.8 g, Protein 16.97 g, Sodium 60.1 g, Fat 6.04* g, Fiber 11.44 g
* 4.62 grams of this fat is giving you 2640 mg Omega 3 (alpha-linolenic acid (ALA)), 660 mg Omega 6 (linoleic acid (LA)), and 990 mg Omega 9 (oleic acid (OA)).
Note: A lot of markets don't carry liquid stevia yet. Here's a good brand you can buy online.