Green For Life, by Victoria Boutenko is a good read in which Victoria talks about her research and decisions to begin eating green smoothies, which are food made from mainly green, leafy vegetables, that are blended up and drank. The theory is that the blending allows us to digest the nutrients in green, leafy vegetables, which are is healthiest type of food.
There are recipes at the back of the book, but I have found it simpler to read the book, throw everything into a blender, and create my own. The trick is adding enough fruit to make it sweet enough to be palatable.
There is some weird scientific stuff in the book, too. Statements that microorganisms can change some elements into other elements, such as calcium to magnesium, and sodium into potassium. That seems physically impossible.
For overall health and nutrition, I recommend a quick read and follow the recipes.