August 2014

High Fiber Diet

High Fiber Diet

If your doctor has placed you on a high fiber diet, or if you want to be on a high fiber diet then you will want to know what you can and should eat to maintain a high fiber diet. When eating out it is essential to know how to order and what to order in order to maintain a high fiber diet. The problem you will face is that most foods sold or prepared in restaurants are pre-processed and there is a preponderance of white flower and low fiber types of foods that are usually on the menu.

Soluble and Insoluble Fibers

Sources of dietary fiber are usually divided according to whether they are water-soluble or not. Both types of fiber are present in all plant foods, with varying degrees of each according to a plant plant’s characteristics. Insoluble fiber possesses water-attracting properties that help to increase bulk, soften stool and shorten transit time through the intestinal tract. Soluble fiber undergoes metabolic processing via fermentation, yielding end-products with broad, significant health effects. For example, plums (or prunes) have a thick skin covering a juicy pulp. The plum's skin is an example of an insoluble fiber source, whereas soluble fiber sources are inside the pulp. Other sources of insoluble fiber include whole wheat, wheat and corn bran, flax seed lignans and vegetables such as celery, green beans and potato skins.

Whole grains, seeds and nuts are now known to reduce risk of some of the world’s most prevalent diseases:

Obesity, diabetes, high blood cholesterol, cardiovascular disease, and numerous gastrointestinal disorders. In this last category are constipation, inflammatory bowel disease, ulcerative colitis, hemorrhoids, Crohn’s disease, diverticulitis, and colon cancer--all disorders of the intestinal tract where fermentable fiber can provide healthful benefits.

Insufficient fiber in the diet can complicate defecation. Low-fiber feces are dehydrated and hardened, making them difficult to evacuate -- defining constipation and possibly leading to development of hemorrhoids.

What Exactly Is Dietary Fiber?

In June 2007, the British Nutrition Foundation issued a statement to define dietary fiber more concisely and list the potential health benefits established to date:

‘Dietary fiber’ has been used as a collective term for a complex mixture of substances with different chemical and physical properties which exert different types of physiological effects. The use of certain analytical methods to quantify ‘dietary fiber’ by nature of its indigestibility results in many other indigestible components being isolated along with the carbohydrate components of dietary fiber. These components include resistant starches and oligosaccharides along with other substances that exist within the plant cell structure and contribute to the material that passes through the digestive tract. Such components are likely to have physiological effects. Yet, some differentiation has to be made between these indigestible plant components and other partially digested material, such as protein, that appears in the large bowel. Thus, it is better to classify fiber as a group of compounds with different physiological characteristics, rather than to be constrained by defining it chemically.

1.    Improvements in gastrointestinal health
2.    Improvements in glucose tolerance and the insulin response
3.    Reduction of hyperlipidemia, hypertension and other coronary heart disease
        risk factors
4.    Reduction in the risk of developing some cancers
5.    Increased satiety and hence some degree of weight management

It is important to recognize that effects of fiber are dependent on the type of fiber in the diet. The beneficial effects of high fiber diets are the summation of the effects of each of the different types of fiber present in your diet. Hence the goal is to order foods with many different types of fiber, or maybe we should say ordering many different foods that are high in fiber. By doing this you increase the overall benefits of fiber, create a more varied and interesting diet and allow a broader selection of foods, tastes as well as nutrients from these foods.

Guidelines on Fiber Intake

The American Dietetic Association (ADA) recommends a minimum of 20-35 g/day for a healthy adult depending on calorie intake (e.g., a 2000 cal/8400 kJ diet should include 25g of fiber per day). The ADA's recommendation for children is that intake should equal age in years plus 5 g/day (e.g., a 4 year old should consume 9 g/day). No guidelines have yet been established for the elderly or very ill. Patients with current constipation, vomiting, and abdominal pain should see a physician. Certain bulking agents are not commonly recommended with the prescription of pain medications because the slow transit time mixed with larger stools may lead to severe constipation, pain, or obstruction.

Current recommendations from the United States National Academy of Sciences, Institute of Medicine, suggest that adults should consume 20-35 grams of dietary fiber per day, but the average American's daily intake of dietary fiber is only 12-18 grams. The American Dietetic Association recommends consuming a variety of fiber-rich foods.

Soluble fiber is found in varying quantities in all plant foods, including:

•    Legumes (peas, soybeans, and other beans)
•    Oats, rye, chia, and barley
•    Some fruits and fruit juices (particularly prune juice, plums and berries)
•    Certain vegetables such as broccoli and carrots
•    Root vegetables such as potatoes, sweet potatoes, and onions (skins of these
      vegetables are sources of  insoluble fiber)
•    Psyllium seed husk (a mucilage soluble fiber).

Legumes also typically contain shorter-chain carbohydrates indigestible by the human digestive tract but which may be metabolized by bacterial fermentation in the large intestine (colon), yielding short-chain fatty acids and gases (flatulence).

Sources of insoluble fiber include:

•    Whole grain foods
•    Bran
•    Nuts and seeds
•    Vegetables such as green beans, cauliflower, zucchini, and celery
•    the skins of some fruits, including tomatoes

The five most fiber-rich plant foods, according to the Micronutrient Center of the Linus Pauling Institute, are legumes (15-19 grams of fiber per US cup serving, including several types of beans, lentils and peas), wheat bran (17 grams per cup), prunes (12 grams), Asian pear (10 grams each) (3.6% by weight), and quinoa (9 grams).

Notes and interesting Facts regarding fiber and high fiber diets:

The soluble fiber in oats binds some of the cholesterol in your digestive tract. This cholesterol is "trapped" and some of it is removed from your body naturally. Oats contain more soluble fiber than whole wheat, rice or corn. In addition to soluble fiber, oats contain vitamins, minerals and unique antioxidants, which help make oats healthy.

Remarkable among plant foods, the Amazonian palmberry, açaí (Euterpe oleracea Mart.), has been analyzed by two research groups reporting its content of dietary fiber is 25-44% of total mass in freeze-dried powder.

Rubus fruits such as raspberry (8 grams of fiber per serving) and blackberry (7.4 grams of fiber per serving) are exceptional sources of fiber.

Fiber sources improve absorption of minerals, especially calcium.

Soluble fibers yield the important short-chain fatty acids that affect blood glucose and lipid levels, improve the colonic environment and regulate immune responses.


When dining out make sure that you have at least 4 to 6 portions of vegetables, raw or steamed, soups can provide some fiber but generally cooked or especially overcooked vegetables have less valuable fiber and while they do not have to be avoided, the you should make sure that they do not represent the bulk of your fiber intake.

A salad before or after dinner, one or two vegetables with dinner and fruit for desert is an excellent way to get a good deal of fiber in your  diet. Portions should be between 4 to 6 ounces of cooked or steamed vegetables, a normal or large salad and one or more pieces of fruit daily.


For more information on High Fiber Diet and to see what a high fiber diet looks like, click here.