How does eating fiber affect my health?

Dr. Michael Roizen, MD
Internal Medicine
Fiber is a key reason that diets high in fruits, vegetables, and grains are good for you. People who eat a lot of fiber have significantly lower rates of aging. The person who eats at least 25 grams of fiber a day has a RealAge (physiologic age) as much as three years younger than that of the person who eats only 12 grams of fiber a day, the national average.

Fiber is found solely in plant foods and is largely indigestible, passing through the digestive tract intact. Therefore, it contains no calories but makes you feel full sooner and helps control overeating. Insoluble fiber does not readily dissolve in water and is not broken down by intestinal bacteria. This form of fiber can be found in many foods: grapefruit, oranges, grapes, raisins and dried fruit, okra, sweet potatoes, peas, zucchini, whole wheat bread, granola, papaya, and peaches. While this type of fiber is not as effective as soluble fiber at decreasing your Lousy low-density lipoprotein (LDL) cholesterol (bad cholesterol) levels, it still makes your RealAge younger. Soluble fiber does dissolve or swell in water. It helps regulate metabolism and digestion and stabilizes blood glucose levels by moderating the rate of nutrient absorption. Soluble fiber is found in grains such as oats, oatmeal, barley, and rye; legumes such as beans, peas, and lentils; and cereals such as Cheerios. Fiber, whether it's soluble or insoluble, slows the emptying of the stomach and first part of the intestine, making you feel fuller and less hungry four to eight hours later. Fiber in your breakfast will make you less likely to want a large afternoon snack.

In a study of forty-three participants at Northwestern University, a 10-gram increase in the daily intake of cereal fiber decreased the risk of heart attack by 29 percent (making a fifty-five-year-old's RealAge 1.9 years younger). It does not take much cereal to produce a definite effect: In the 2003 evaluation of the National Health and Nutrition Follow-Up Study, a 5-gram increase in cereal fiber-an easy addition to breakfast-reduced all-cause death rates by 12 percent. That alone makes your RealAge about 0.8 years younger. Individuals who eat less fiber also tend to have worse overall diets and to be more sedentary.

A high-fiber diet helps reduce the incidence of hemorrhoids, a condition that can be provoked by excess pressure on the bowel walls caused by the forced bowel movements that often accompany a low-fiber diet.
The RealAge Makeover: Take Years off Your Looks and Add Them to Your Life

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The RealAge Makeover: Take Years off Your Looks and Add Them to Your Life

Why not live at 60 feeling like you did at 35?Thousands of Americans are younger today than they were five years ago. How is that possible? By following the specific recommendations that reverse...
Marisa Moore
Nutrition & Dietetics

Getting the recommended daily fiber can have a positive impact on your health.  In fact, a high fiber diet has been shown to

  • Help maintain a healthy digestive tract and reduce constipation.
  • Regulate blood sugar levels in those with diabetes.
  • Lower total and LDL (bad) blood cholesterol levels.
  • Help with weight management by creating a longer feeling of fullness.

While these are great benefits, if you are not currently following a high fiber diet, take it slow.  Too much fiber, too soon can be a shock to the digestive system and you may experience gas, bloating or other unpleasant side effects.  Start slow and work your way up to the recommended 25-38 grams of fiber per day.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.