Here's what Dr. Barnard states...for every additional 14 grams of fiber that you consume, you will reduce calorie intake by 10%. He recommends 40 grams of fiber per day. The graphic below is from Dr. Neal Barnard's presentation on PBS.
This is one of the things that you will learn in Feed Your Head. Dr. Barnard goes on to talk about how easy it is to lose weight. Everyone, and I do mean everyone, who catches on to the concept, says the same thing. I certainly do.
Sampling of high-fiber foods.
Source: The Full Plate Diet