Although both obesity and irritable bowel syndrome are common problems, it is not easy to prescribe a diet without considering your own unique food preferences, calorie vices, and symptom triggers. The best diet for you will be highly personalized. Here is some general advice for you to work with:
Avoid fats. Fats are calorie-loaded, so they are an obvious contributor to obesity. Fats also contribute to the abdominal cramping episodes that can be common in irritable bowel syndrome. Fats in your stomach cause your colon to respond to a meal with a more exaggerated set of contractions, so that the “gastrocolic reflex� that occurs after eating can be more painful. Whereas cholesterol concerns have caused doctors to describe different fat types as either “good fats� or “bad fats,� all fats can cause problems if you have an irritable bowel or a weight concern.
Eat more soluble fiber. Fiber is food residue that your digestive enzymes can't break down, so it travels the whole length of your colon and exits as stool. Some forms of fiber (such as the fiber contained in oats, apples, lentils and barley, and also in highly processed grain foods such as white flours and white rice) are able to mix evenly with water, forming a soft gel. This fiber type is known as soluble fiber, and this fiber can improve every symptom of an irritable bowel. Soluble fiber gel thickens stool that would otherwise cause diarrhea, and it prevents constipation by softening and hydrating stool, making it easier to propel along the colon. In general, fiber is a great help to weight management. Since it is not itself absorbed, it does not contribute calories. Unfortunately, though, many sources of soluble fiber also contain large quantities of “carbs� -- white flour and white rice, pasta or polenta would be examples. Carbs can contribute to weight concerns because they trigger you to snack between meals. In your case, this makes my next piece of advice important…
Eat small, slow, and frequent meals. If you keep your portions small, this will help to reduce your total calories; frequent meals may offset the snacking urges from carbs that are associated with soluble fiber sources. Hurried eating or drinking can cause you to have increased gas due to swallowed air, so slow meals can improve bloating symptoms.
