Patients are always encouraged to include more fiber in their diet and for good reason. Fiber is most often recommended to treat disorders related to the functioning of the intestinal tract. Constipation is probably the number one GI disorder for which a high fiber diet is recommended. Fiber increases the bulk of the fecal material while at the same time stimulating movement of the feces through the intestine to be eliminated.
Fiber is found primarily in fruits, vegetable and grains, and its comes in differing compositions. Unfortunately, a lot of the foods high in fiber are not in the category of foods people love to eat. Big Mac’s, Whopper’s, and Quarter Pounders are not known for their nutritional value or for supplying our bodies with the many benefits of fiber. Instead, many of us have to force ourselves to increase dietary fiber and eat the kinds of foods that are good for us. We’re often unsuccessful in that attempt.
In addition to its GI benefits, fiber is credited with lowering our risk of coronary artery disease (CAD), stroke, high blood pressure, obesity, diabetes, and cancers of the colon, rectum, breast, and stomach. Fiber has a significant anti-inflammatory effect which is largely responsible for its preventing CAD. And along that line we see reductions in cholesterol and blood sugar as well.
As mentioned above, fiber can be soluble or insoluble. For GI problems, insoluble fiber is the recommended type. And foods containing soluble fiber are the variety that benefits cardiovascular health. Soluble Fiber foods would include oat bran, nuts, barley, seeds, beans, citrus fruits, peas, psyllium supplements, and methyl cellulose, which sometimes we must force ourselves to eat. Soluble fiber is a carbohydrate that dissolves in water to form a gel-like substance that moves through the body undigested.
Insoluble fiber, which benefits digestive health issues, consists of wheat bran, whole grains, celery, kale, grapes, tomatoes, potatoes, and fruit skins. These are a bit more desirable dietary food items. Insoluble fiber does not dissolve in water and has a mild laxative effect.
The recommended daily amount of fiber is 25-30 grams. That’s a lot of fiber and most people fall way short of that amount. Metamucil, a very popular fiber supplement for constipation, contains only 3-6 grams of fiber per dose, and taking a larger amount is difficult to take at one sitting. Metamucil and fiber cereals attempt to keep patients loose and going. According to my reference, apples are an excellent source of both soluble and insoluble fiber containing 4.4 gms per apple. So apples are close to being nature’s ideal source of fiber.
A high fiber diet is a lifestyle change. It’s a major lifestyle change for patients who are accustomed to a high fat diet. Going from hamburgers to fruits, vegetables, grains, seeds, and beans is a difficult transition for Americans. If one were to have consumed a high fiber diet since childhood, adjusting to it is not a concern. There is no adjustment. Those patients will not have GI problems as readily as if they were on a high fat diet long term.
Suffice it to say, a high fiber diet is better for everyone and should be encouraged.
Reference: Kim GE. Not All Fiber is Equal: What Clinicians Need to Know. medscape.com/2026 May 13.
