Fiber 101

What is Fiber?

Fiber is essentially any edible compound which does not get broken down by digestive enzymes in the body.  When it comes to weight loss, fiber-rich foods and fiber supplements can be your key to success.  The reason is because fiber compounds are natural appetite suppressants which also have the added benefits of keeping your body healthy.

Types of Fiber

There are various ways that you can divide fiber into types.  Firstly, fiber can be called either dietary fiber or functional fiber.  Dietary fibers are sources of fiber which are naturally found in foods we eat, such as the pectin found in apples and many other fruits.  Functional fiber is isolated from its source and used as supplements or food additives. Chitin – a fiber isolated from crustacean shells and often sold for weight loss – is a type of functional fiber.

Another way of typing fiber is by viscous or nonviscous.  Viscous fiber will turn into a gel-like substance when in water.  For weight loss, these types of fiber are very useful because they combine with foods you eat.  It then takes longer for your body to break down the foods in the viscous solution so you feel full longer.  The most common way of typing fiber is soluble and insoluble.  These terms are similar to viscous and nonviscous but there are differences.  A soluble fiber will break down in water whereas a insoluble fiber will not.  Some soluble fibers will form a viscous gel when in water.

Role of Fiber in the Body

Fiber is incredibly important for regulating bowel movements.  Since fiber is not digested by the body, it instead passed out of the digestive track and can clean out the bowels in the process.  Fiber is the body’s natural way of fighting constipation.  It also fights diarrhea too because fiber will absorb water so bowel movements are not runny.  Fiber is also incredibly important for fighting off bowel-related diseases, including cancer.  As the fiber goes through your digestive tract, toxins adhere to it and are excreted along with the fiber.

Studies show that fiber is very effective in lowering levels of LDL (unhealthy) cholesterol in the body.  The way that fiber fights bad cholesterol is by binding to bile acids and causing them to get excreted along with the fiber.   Since your liver uses cholesterol to produce more bile, the fiber causes a reduction in LDL cholesterol.

How Fiber Helps Weight Loss

When it comes to weight loss, viscous fiber is very effective in suppressing appetite.  When you consume viscous fiber with a meal, the fiber will bind to the foods you have eaten and form a gel-like substance.  The body cannot break down this gel-like substance into glucose (blood sugar) as quickly.  Instead of getting a sudden surge of glucose in the blood (such as occurs when you eat a starchy food without any fiber), the glucose is slowly released into the blood and you get a steady supply of energy.

Blood sugar levels are directly linked to your sense of hunger.  When blood sugar levels plummet, you become hungry.  So long as your blood sugar levels are steady, your brain will not trigger a hunger response.  This is the key to fiber’s appetite-suppressing effect; it makes you feel full for much longer after eating a meal.

Sources of Fiber

Fiber is primarily found in fruits and vegetables whereas meat and dairy products have little or no fiber.  You can find out the fiber content of food items at the USDA National Nutrient Database.


Food Amount


Navy beans 1 cup


Lentils, cooked from dried 1 cup


Artichokes, cooked 1 cup


Kidney beans, canned 1 cup


Refried beans, canned 1 cup


Raspberries, fresh 1 cup


Instant oatmeal, cooked 1 cup


Rice, long-grained brown, cooked 1 cup


Almonds 1 ounce


Mushrooms, cooked 1 cup


Peanuts 1 ounce


The recommended daily serving of fiber for adult women is about 25 grams and for adult men 38 grams.  Unfortunately, it is difficult to get enough fiber when eating a diet high in processed foods, such as common in the West.  People who want to lose weight and also improve their overall healthy should opt for fiber-rich foods like fruits, vegetables, legumes, and whole grains. Aside from the fiber content of these foods, they usually have other weight loss benefits, like being low-calorie but high in nutrients.

For people who are unable to stick to a fiber-rich diet, a fiber supplement can help weight loss.  No fiber supplement is going to be a magic bullet and help you lose weight rapidly.  However, fiber weight loss supplements can help curb appetite which makes it easier to stick to a low-calorie diet crucial for losing weight.


Higdon, Jane, PhD. “Fiber.” Lpi.oregonstate.edu. Linus Pauling Institute Micronutrient Research for Optimum Health. Dec 2005, updated Aug 2009. Web.

Brown, Lisa, Bernard Rosner, Walter W Willett, and Frank M Sacks. “Cholesterol-lowering effects of dietary fiber: a meta-analysis.” American Journal of Clinical Nutrition, 69.1 (1999): 30-42.

Anderson JW, Baird P, Davis RH et al. “Health benefits of dietary fiber”. Nutritional Review 67.4(2009):188–205.


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