After reading this book about a year and a half ago....
I started drinking green smoothies about once a day. My favorite recipe is:
1 C water
then blend in a loosely piled blender full of spinach
When that is pureed, add 1 container sweetened yogurt, 1 banana, and about 3/4 C of frozen berries.
Blend on high until smooth.
I did lose 20 pounds after eating these daily for a month or so. I was also breastfeeding at the time, so take it for what you will :).