Doctor’s Tip: Why is fiber so fabulous? |

Doctor’s Tip: Why is fiber so fabulous?

Dr. Greg Feinsinger

Dr. Greg Feinsinger
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There is a severe fiber deficiency in America, the land of plenty. Only 3 percent of us eat the minimum 32 grams of fiber a day recommended by U.S. guidelines. Dr. Michael Greger notes in his book “How Not to Die” and his website that, based on analysis of fossilized stool (he calls this “Paleopoop”) and the diets of primitive cultures existing today, we evolved over millions of years eating 100 grams or more of fiber a day. Ideally we still should do that.

There are two types of fiber. Soluble fiber means it is soluble in water, and examples are oats (the gelatinous substance when you cook oatmeal), peas, beans, apples, citrus, carrots and barley. Foods with insoluble fiber include whole grains, wheat bran, nuts, beans, cauliflower and potatoes eaten with the skin. A large portion of insoluble fiber-containing foods are digested, but the insoluble part of them goes right through the GI tract undigested.

Animals have bones that hold them up, and plants have fiber. Meat, dairy and other animal products do not contain fiber, but all unprocessed plant products do. We know that people who eat lots of fiber have a lower incidence of several diseases, but it’s difficult to tell in studies whether these health benefits are from the fiber, from the increase in the consumption of plant products or from decrease in the intake in animal products. However, Dr. Michael Greger, Dr. Joel Fuhrman, Dr. Dean Ornish, and other nutrition experts describe well-done studies that show that eating more fiber offers the following benefits:

• Fiber has no calories, yet due to its bulk it fills people up, thereby preventing and reversing obesity.

• It lowers blood pressure.

• It lowers cholesterol.

• It prevents insulin spikes and helps prevent and reverse prediabetes and type 2 diabetes.

• It decreases strokes and heart attacks.

• It treats and prevents constipation by increasing stool bulk and decreasing transit time (the time it takes for stool to go through the GI tract).

• By decreasing straining to have a stool, fiber decreases the incidence of hiatal hernia, GERD (acid reflux), hemorrhoids, hernias and diverticulosis (small pouches off the wall of the colon that can lead to diverticulitis).

• It decreases the incidence of breast and colon cancer.

• Fiber binds toxins such as heavy metals and removes them in your stool.

• Fiber feeds the good bacteria in your gut (microbiome), which influence many aspects of your health. Probiotics are supplements containing good bacteria whereas prebiotics like fiber feed and support the good bacteria you already have.

How do you increase your intake of fiber? Basically, decrease or avoid animal products and eat a lot of vegetables including legumes, fruit and unprocessed grains. In general you want to buy your food in the produce section of the grocery store. When you do buy something in a box or wrapper (e.g. bread) check the food label for the serving size and then fiber per serving. If the total carb:fiber ratio is 5:1 or less, the product has lots of fiber and whole grains (multiply the fiber number by 5 and that number should be greater than the number for total carbs). Here are fiber contents of some foods that don’t come in a wrapper or box: black beans, 1 cup, 19 grams of fiber; cooked broccoli, 3/4 cup, 7 gm; oatmeal, 3/4 cup, 7.7 gm; garbanzo beans, 1 cup, 12 gm; 3 dried figs, 10.5 gm; Swiss chard cooked, 1/2 cup, 4 gm; one pear, 4 gm; raspberries, 1/2 cup, 4.6 gm; and one yam with the skin, 6.8 gm.

How about taking fiber supplements such as Metamucil or Benefiber? As is always the case, the pharmaceutical industry cannot complete with Mother Nature. There have been a few studies that questioned some of the above benefits of fiber, but for the most part they were done with fiber supplements (in some cases natural fiber was used but in amounts far below ideal). So there is no substitute for increasing fiber-containing foods in your diet.

Dr. Feinsinger, who retired from Glenwood Medical Associates after 42 years as a family physician, now has a nonprofit Center For Prevention and Treatment of Disease Through Nutrition. He is available for free consultations about heart attack prevention and any other medical concerns. Call 970-379-5718 for an appointment. For questions about his columns, email him at

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