But according to a rule of physics called LaPlace's Law, the tension in the wall of a cylinder is inversely proportional to the cylinder's diameter. Thus, fiber, which gently stretches the bowel wall, actually decreases the tension in the bowel, says Schuster. A high-fiber diet will probably produce gas at first, but that usually lasts for only about three weeks, says Schuster. He advises patients to increase their fiber gradually, since adding too much fiber too rapidly will cause persistent gas pains. Although bran products may help some patients, others cannot tolerate them.
Some physicians recommend bulking agents made from psyllium seeds.
Schuster also advises against laxatives. Getting enough sleep and physical exercise also helps keep the bowels regular. Avoid culprit foods. Fatty foods aggravate symptoms in many people with IBS, says Schuster. Fats slow down the digestive tract, gumming up the works in an already irregular system.