For years, any weight-loss aficionado could easily tell you the best sources of dietary fiber: whole grains, legumes, fruits, and vegetables. But in today’s environment, things have changed. Grocery store shelves have become crowded with traditionally low-fiber foods that are now packed with fiber, like candy, ice cream, and artificial sweeteners.
According to TOPS Club, Inc. (Take Off Pounds Sensibly), the nonprofit weight-loss support organization, these “new fiber” foods may not yield the same health benefits as their traditional high-fiber food counterparts.
Dietary fiber – also called roughage – is defined by the Institute of Medicine as the edible, nondigestible component of carbohydrate and lignin found naturally in plant food. Fiber is not digested or absorbed in the small intestine, and it does not contribute calories; rather, bacteria in the stomach metabolize the fibrous parts of food. When you eat a food that contains a natural source of dietary fiber, you are said to be eating intact fiber.
Added fiber consists of isolated, nondigestible carbohydrates that have beneficial physiological effects in humans. These fibers can be synthetically manufactured or derived from other plant or animal sources. An example of an added fiber is pectin extracted from citrus peel and used as a gel in making jam or jelly. Generally, added fiber is referred to as isolated or functional fiber.
Total fiber is the sum of dietary (or intact) fiber plus added (or isolated or functional) fiber. Things can seem confusing on the Nutrition Facts panel of food packaging because “dietary fiber” includes all sources of fiber in that food, whether they are from intact or isolated sources. This is why you can see upwards of ten grams of dietary fiber listed for a fiber-fortified flour tortilla that traditionally would have only one or two grams of fiber.
Fiber can help lower cholesterol, regulate blood sugar, and promote satiety or the feeling of fullness.
According to The Institute of Medicine, women ages 50 and younger should consume 25 grams of fiber per day. Women ages 51 and older should aim for 21 grams per day. For males, those 50 and under need 38 grams per day, and men ages 51 and older should consume 30 grams of fiber per day.
Isolated vs. Intact Fiber
According to Katie Clark, M.P.H., R.D., C.D.E., Assistant Clinical Professor of Nutrition at the University of California – San Francisco and nutrition expert for TOPS, the health benefits of intact fiber are widely accepted among health professionals.
Researchers who study the effects of fiber on health have done so largely by analyzing the dietary fiber that occurs naturally in high-fiber foods. But do the health benefits of dietary fiber extend to synthetically manufactured or extracted fibers added to traditionally low-fiber foods? The American Dietetic Association (ADA) maintains that, “Whether isolated, functional fibers provide protection against cardiovascular disease remains controversial.” The ADA’s position paper on dietary fiber goes on to say, “Longer-term studies of fiber intake which examine the effects of both intrinsic (intact) and functional (isolated) fibers…are required.”
“Because we don’t know to what degree the health benefits of dietary fiber are attributable to intact fibers (the additional nutrients in those high-fiber foods), most dietitians and nutrition professionals are recommending that consumers focus on eating foods that are naturally high in fiber,” says Clark.
Whole foods such as whole grains, legumes, fruits, and vegetables are not only high in fiber, but low in salt, devoid of added sugar, and tend to be lower in calories than processed and packaged foods. Many of the isolated fiber foods on the market are highly processed and are high in salt, added sugars, and extra calories.
“Much like the notion that ‘organic junk food is still junk food,’ keep in mind that a ‘high-fiber cookie is still a cookie!’” notes Clark.
Side of Package Sleuthing
To determine whether the fiber in a food product comes from an intact or isolated source, you should search the ingredients list on food packaging.
The most common isolated fibers that manufacturers use to bulk-up traditionally low-fiber foods are:
• Inulin (chicory root)
• Oat fiber
• Resistant start
Keep in mind that rapidly increasing the amount of fiber in your diet can lead to gas, bloating, and other gastrointestinal discomfort. Drinking more water alongside increasing fiber intake and slowly increasing fiber intake by a few grams per day can help alleviate symptoms.
By increasing the amount of whole grains and legumes in your diet and making sure to eat five to seven servings of fruits per day, it’s quite possible to meet your dietary fiber needs without eating fiber-fortified or isolated fiber foods. Eating whole foods that are naturally high in fiber are oftentimes more satiating – and less expensive – than foods that contain functional fiber or are fiber-fortified.
“Fiber can be an important tool in weight loss, diabetes management, and reducing the risk for other chronic diseases,” says Clark. “When selecting high-fiber foods, look for whole fiber foods over fake fiber foods to maximize your health potential.”
TOPS Club Inc. (Take Off Pounds Sensibly), the original, nonprofit weight-loss support and wellness education organization, was established more than 62 years ago to champion weight-loss support and success. Founded and headquartered in Milwaukee, Wisconsin, TOPS promotes successful, affordable weight management with a philosophy that combines healthy eating, regular exercise, wellness information, and support from others at weekly chapter meetings. TOPS has about 170,000 members in nearly 10,000 chapters throughout the United States and Canada. Visitors are welcome to attend their first TOPS meeting free of charge. To find a local chapter, view www.tops.org or call (800) 932-8677.