We've all heard that we need to be eating more fiber. Generations of grandmothers have extolled the virtues of roughage.
Today nutritionists echo that thought. But the benefits of a high-fiber diet appear to be far more considerable than grandmother may have ever realized.
Recent research offers some compelling reasons to up your daily dose of fiber. Diets high in fiber have been shown to reduce the occurrence of several chronic diseases, including diabetes, heart disease and possibly cancer. As a result, in 2002 the National Academy of Sciences' Food and Nutrition Board recommended for the first time that Americans increase their daily fiber intake to 38 grams for men and 25 grams for women, the levels they found protective against heart disease.
Yet most Americans eat half the recommended amount of fiber, relying instead on refined foods. If you're on a low-carb diet, you may not consume any fiber.
Fiber is the indigestible part of plant foods, such as fruits, vegetables, whole grains, nuts and legumes, that travels unchanged through the intestines. Fiber is found mostly in carbohydrates and comes in many forms. It is concentrated in the skin of fruits and vegetables, such as apples, corn and legumes; in the seeds of vegetables and fruits, such as cucumbers and berries; and in the germ and bran (or coating) surrounding kernels of wheat and other grains. (This portion of the grain is removed to create white flour and other refined grains.)
Although it may be tempting to ignore grandmother's advice, it's definitely not in your best interest. Recent research indicates that fiber results in:
Easier Weight Loss "Not eating enough fiber may be one reason why people are getting fatter," says David J.A. Jenkins, professor of nutrition and medicine at the University of Toronto and a member of the NAS expert panel. A study published in the American Journal of Clinical Nutrition last year found that women with the highest intake of fiber had a 49 percent lower risk of weight gain when compared with women on low-fiber diets.
Very little, if any, fiber is actually digested. So, with foods high in fiber, only a portion of the calories that you eat actually count, which means high-fiber diets tend to be somewhat lower in calories than their low-fiber counterparts.
High-fiber foods are also bulky and contain a lot of water, which means they can fill you up with fewer calories than low-fiber foods. Studies conducted by Barbara J. Rolls, professor of nutritional sciences at Pennsylvania State University, during the past five years show that consuming high-fiber foods, such as vegetables, before or during a meal decreased total intake by 100 calories. While saving 100 calories a day may not sound like much, it translates into 10 pounds in one year.
Digestive Disorders The dearth of fiber in our diets may be a key reason digestive disorders are on the rise. For many digestive disorders, including reflux disease, constipation, diarrhea, hemorrhoids, diverticulosis, ulcerative colitis, Crohn's disease and irritable bowel syndrome, a higher-fiber diet usually relieves symptoms and can even prevent the disorder in the first place, according to Leslie J. Bonci, a registered dietitian at the University of Pittsburgh Medical Center.
Bonci recommends that most people with these disorders eat more fiber rather than avoid it. "Fiber increases bulk and motility, and this relieves pressure, keeps everything regular and more comfortable for the whole gamut of intestinal disorders," she said.
Lowered Risk of Diabetes Numerous studies have shown that diets high in fiber can help to control diabetes. It's been estimated that fiber -- especially cereal fiber from whole grains -- reduces diabetes risk by about 35 percent, according to Simin Liu, assistant professor of medicine at Harvard University, in an article published last year in the American Journal of Clinical Nutrition.
Diabetes is characterized by high blood sugar. Because high-fiber foods tend to have a lower glycemic index than low-fiber foods, they cause blood-sugar levels to rise less. Studies have shown that people with high-fiber diets usually have lower fasting insulin levels, which is an indicator of overall lower blood sugar.
Also, high-fiber foods contain many nutrients that may help control diabetes. Magnesium -- a nutrient found in whole grains, legumes, tofu and some vegetables -- can improve insulin resistance, one of the causes of Diabetes Type 2. Vitamin E, found in whole grains and nuts, may also improve insulin resistance.