We’ve said it before and we’ll say it again: You can’t get too much fiber. Our Paleolithic ancestors consumed between 50-100 grams a day. The National Cancer Institute recommend between 25-35 grams a day; for adults under 50 and the Institute of Medicine suggests a minimum of 38 grams a day for men and 25 for women. Do you know what the average American gets? Eight to eleven paltry grams a day.
Fiber is the part of food that cannot be digested or broken down by the human body. It passes through our body intact, cleaning our intestines as it travels through. This is why fiber promotes good intestinal function, although it adds almost no calories to the diet. You can think of fiber as a scrub brush for the intestines. Low fiber diets are associated with constipation, irritable bowel syndrome, diverticulosis and colon cancer. High fiber diets tend to prevent these problems and diseases. They’re also associated with better weight management- fiber makes you feel full and satisfied. It also slows the entrance of glucose (sugar) into your bloodstream, making it especially useful for controlling the “blood sugar roller coaster”. Not surprisingly, recent studies have shown that a high fiber diet can reduce the risk of diabetes, not to mention heart disease.
Fiber comes in two forms: soluble and insoluble. Soluble fiber is made up of sticky substances like gums and pectin, which form a gel-like substance when mixed with liquid. The gel binds with cholesterol and bile acids in the small intestine and eliminates them from the body. Since bile acids are made from cholesterol, more of your body’s cholesterol is used up in replenishing the bile acids. Hence, soluble fiber’s well deserved reputation for lowering cholesterol. Best sources of soluble fiber: oats, especially oat bran, barley, dried beans, soybeans, apples, nuts, flax seeds and other fruits and vegetables.
Insoluble fiber does not dissolve in water. It absorbs water as it passes through the body, which adds bulk to the stool and speeds up transit time, preventing constipation and diverticulosis. It also helps reduce the risk of colon cancer by moving toxins and cancer causing substances through the digestive tract more quickly. The best sources of insoluble fiber are wheat bran and whole grain products. Most plant foods contain both types of fiber. Insoluble fiber is more common, found in most fruits and vegetables as well as beans, grains and nuts.