About a year ago, I googled something along the lines of "Does Fiber Help you feel fuller?" I've found that when I eat fiber in the morning with my breakfast, I seem to stay much fuller for the rest of the day.
I know, I know - "Duh. Everyone knows that." Many people know it, but it impacted me enough that I felt it was worth repeating.
In my research, I found that besides giving one a feeling of satiation and helping to digest food properly that dietary fiber also helps your body release nutrients more evenly from the digestive system, keeping you more even keeled throughout the morning.