The small intestine absorbs nutrients and some water from digested food. The vast majority of food absorption happens in the small intestine. The small intestine is composed of three sections: the duodenum, jejunum, and ileum. Humans have anywhere from 10-16 feet of small intestine. The small intestine is quite adaptive; in fact, even with removal of up to 40% of it, appropriate digestion is still possible.
From the small intestine, enteric contents then pass into the large intestine (colon) for resorption of water. Constipation is a dysfunction of the large bowel. Constipation has numerous causes. Most commonly, constipation results from a low-fiber diet coupled with inadequate water intake. Removal of small intestine does not contribute to the development or worsening of constipation.