Do you find that you are constantly hungry? If so, you might need to increase your protein and fiber consumption. Studies show that protein helps to increase satiety (fullness).
In a study led by the University of Washington School of Medicine, participants who increased their protein intake from 15 to 30 % of their daily caloric intake noticed less hunger and lost more weight. Another benefit of protein is that your body burns more calories to break down the protein into a useable form and digest it.
Taken from the Dr. A's Habits of Health