Transit time is slowest in
I. The first part of a test meal reaches the cecum in about 4 h, and all the undigested portions have entered the colon in 8 or 9 h.
II. On average, the first remnants of the meal traverse the first third of the colon in 6 h, the second third in 9 h, and reach the terminal part of the colon (the sigmoid colon) in 12 h. From the sigmoid colon to the anus, transport is much slower.
III. When small colored beads are fed with a meal, an average of 70% of them are recovered in the stool in 72 h,
but total recovery requires more than a week.
IV. The time taken for food or other ingested objects to transit through the gastrointestinal tract varies depending on many factors, but roughly, it takes 2.5 to 3 hours after a meal for 50% of stomach contents to empty into the intestines and total emptying of the stomach takes 4 to 5 hours. Subsequently, 50% emptying of the small intestine takes 2.5 to 3 hours. Finally, transit through the colon takes 30 to 40 hours