In people with IBS, diet and stress often seem to cause symptoms. Many people report that their symptoms occur after a meal or when they are under stress.
Eating causes contractions or spasms of the colon. Normally, this response may cause an urge to have a bowel movement within 30 to 60 minutes after a meal. In people with IBS, the urge may come sooner with cramps and diarrhea. Contractions may be stronger after a large fatty meal. Many people with IBS learn to avoid certain foods, beverages, and medicines that seem to make their symptoms worse.
Stress can cause contractions of the colon in people with IBS. The reasons for this are not clear, but scientists point out that the colon is controlled partly by the nervous system. Learning relaxation methods and other ways to reduce stress can be helpful. Counseling and support help relieve IBS symptoms in many people.