The time needed for food to pass from the mouth to the anus. Passage time correlates with the amount of fiber in the diet. High-fiber diets pass more rapidly than low-fiber diets. There is a large degree of individual variability in passage time. Passage time is increased with exercise as well as with food-borne illness and food ingredient intolerances. Passage time is decreased with high-fat diets. Constipation is characterized by long passage times.