When you complain of belly cramps and alternating constipation and diarrhea, your doctor does a lot of tests. If they are all normal, he tells you that you have irritable bowel syndrome or diverticulitis. He should also tell you that you eat too much flour and other refined carbohydrates.

Most food that you eat is absorbed in your upper intestinal tract, but some non-absorbable starch passes to your colon which is loaded with bacteria that ferment it to release large amounts of gas. If the gas can pass along, it causes no symptoms. However, if anything obstructs the flow of gas, it accumulates behind the obstruction and blows up the tube-shaped colon like a balloon, stretching the colon to its limits and causing pain. Eating food that is low in fiber and high in starch causes hard stool that blocks gas, causing the colon to balloon and form outpouchings, called diverticula, that hurt. When enough gas accumulates, it blows out the hard stool which is followed by diarrhea. Then the process repeats itself to cause alternating constipation and diarrhea.

Most people who suffer from irritable bowel syndrome do not have a serious disease. Fewer than one in 20 suffers from ulcers, cancers or pancreatitis up to 30 years later. The treatment for irritable bowel syndrome is to eat lots of fruits, vegetables, whole grains and beans and avoid high-starch, low-fiber foods such as most bakery products and pastas. Whole grains, seeds, beans and vegetables keeps everything soft by filling with water and letting gas pass on its way. If that doesn't work, 5HT inhibitors such as Alosetron, Granisetron and Ondansetron may help.

The notion that people with diverticulitis need to avoid corn and other seeds (because they "may get stuck in the pockets") is outdated and has never been proven to be an actual concern. If your doctor has given you this instruction, ask him or her to show you data. A healthful diet for a person with diverticulosis includes lots of high-fiber foods, such as nuts and other seeds.