What exactly does fiber do?

Fiber is a plant-derived carbohydrate that 

cannot be digested by 

humans, so it passes through your 

system relatively intact and has 

little to no caloric value.

There are two types of fiber: Soluble 

(dissolves in water) and insoluble 

(does not dissolve in water). Both play an 

important role in optimal 

health and occur naturally -- often 

together -- in foods such as whole 

grains, fruits, vegetables, nuts, seeds 

and beans.

Fiber acts as a natural laxative by 

increasing stool bulk, which allows 

stool to pass more readily through the 

colon. It can also help those 

with loose stools and may play a role in 

the management of irritable 

bowel syndrome. Many types of soluble 

fiber also act as prebiotics, 

feeding healthy bacteria in your gut, 

thereby further contributing to 

colon health.

Fiber, especially soluble fiber, also improves 

blood sugar control by 

slowing down the rate that food empties from 

your stomach, thereby 

delaying the rise in blood sugar after meals 

and preventing excess or 

exaggerated insulin release. Delayed stomach 

emptying may also help 

with weight loss by improving hunger control.

In addition, fiber adds bulk to your diet 

without adding calories and helps 

to reduce the calorie density of your diet, one 

of the most important 

strategies for long-term weight loss. Soluble 

fiber can help lower 

cholesterol, and a high-fiber diet may help 

reduce blood pressure, 

inflammation and reduce your risk of heart 

failure (especially fiber from

 whole grains).

Studies show that those with the highest 

intake of fiber have a significantly 

lower risk of dying of any cause. A recently 

published study by the 

National Cancer Institute that included almost 

400,000 participants found 

that for every 10-gram increase in fiber 

intake, risk of death dropped 

12% in men and 15% in women.

Women should consume about 25 grams of 

fiber per day and men should 

consume 38 grams. The majority of 

Americans get less than half the daily 

recommended amount of fiber

Naturally occurring fiber is generally your 

best bet. Many products, 

including cookies, crackers, drinks, sugary 

cereals and even ice cream, 

are now adding fiber to appear more healthy. 

In most cases, these added 

fibers do not have the same health benefits as 

naturally occurring fiber.

Aim for a variety of sources of naturally 

fiber-rich foods including fruits, 

vegetables, whole grains, nuts, seeds and 

beans to ensure that you get all 

the health benefits -- along with a host of 

other health-promoting vitamins, 

minerals and phytonutrients.

Refined and highly processed grains and fruit 

juices are stripped of their 

naturally occurring fiber (and many 

nutrients), so it is important to choose 

whole foods for optimal health.

If you have trouble getting in adequate 

amounts of fiber daily or suffer 

from bowel problems or high cholesterol, talk 

to your doctor or a 

registered dietitian about adding a fiber 

supplement to your diet.

If you don't currently eat enough fiber, 

increase your fiber intake slowly to 

avoid unpleasant gut symptoms (such as gas 

and bloating) and make sure 

to drink plenty of water.

If you are gluten-sensitive or intolerant, there are a number of gluten-free 

grains, including quinoa, brown rice, oats and 

corn. For a full list of 

gluten-free grains, visit the nonprofit Whole 

Grains Council website.

What burns more calories -- walking or 

running?