By Aaron Gilbert

Getting enough fiber by building your diet around vegetables, fruits, legumes, whole grains, nuts and seeds, is important for overall health and disease prevention.

Aaron Gilbert. Photo by William Lange

What is fiber?

Dietary fiber is a non-digestible polysaccharide, which means it’s a complex form of carbohydrate. These polysaccharides give plants their structure – think plant cell walls.

Types of dietary fiber

We can divide fiber into two general categories based on their structure and what they do in our bodies. Soluble fibers are viscous and fermentable, and can lower our blood cholesterol. Insoluble fibers help to bulk up stool volume and improve motility.

We need both types of fiber in our diets.

Grains, vegetables, legumes, fruits and nuts account for 85 percent of the fiber in the U.S. food supply. These same plant foods provide lots of other nutrients.

However, since we live in a world of refined and fortified foods, there are now “functional dietary fibers.” These are the isolated, non-digestible carbohydrates that fortify foods not usually containing fiber – stuff like “fiber-ed up” Splenda and Apple Jacks. This allows many unhealthy products to claim they are “healthy.”

Why fiber is so important

White flour and white potatoes provide the most fiber to the American diet. This isn’t because these foods contain lots of fiber; it’s because we eat lots of these foods. Legumes only provide about 6 percent of the fiber in the U.S. diet.

In other words, people eating a standard Western diet aren’t getting anywhere near the fiber they should.

A low-fiber diet is associated with many health problems, including:

  • Cardiovascular diseases and high blood fats (Fiber helps bind and eliminate blood cholesterol/fat.)
  • GI disorders, cancers and poor bowel function (Fiber helps keep the GI tract clean and can ease constipation and diverticular disease.)
  • Diabetes (Fiber controls blood sugar, insulin and body fat.)
  • Excess body fat (Fiber contributes to satiety and dilutes energy density.)
  • High blood pressure (See all the above.)

Americans consume about 15 grams of fiber per day on average (17.8 g for males and 13.6 g for females. Refined sugars, oils, dairy products and alcohol contain no fiber and comprise 48 percent of the energy in the average U.S. diet.

When asked about their dietary fiber consumption, 73 percent of individuals with a fiber intake below 20 grams per day think the amount of fiber they ingest is “about right.” The Institute of Medicine recommends 19 to 38 grams of fiber per day based on age and gender.

Women should aim for at least 30 grams of fiber per day. Men should aim for at least 40 grams of fiber per day. When you eat enough fiber, you need to consume enough fluids.

Aaron Gilbert, CSCS, is the owner of Longevity Athletics.


This column appears in the December issue of InMaricopa.


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