We do know now that a diet with plenty of fibers helps against corpulence, high blood pressure, and other factors that increase the chance for a heart disease. The consumed amount of fibers maybe even a more important factor than the amount of fat that is consumed by people!
The food that contains these healthy (natural) fibers is.... right: fruit! (vegetables as well). The American Heart Association advises to consume 25 to 30 grams of fibers out of fresh fruits and/or vegetables. In practice this means: have five to nine portions of fresh fruits or vegetables a day.