Fiber is the part of foods that are indigestible. Your digestive system does not have the capability to break down and absorb this ‘roughage’ and it, therefore, passes through your body intact. Dietary fiber is important for our health and found in numerous foods that we consume on a daily basis.
The fiber we acquire in our diets can be divided into two sub-categories: Soluble fiber, and insoluble fiber.
Soluble fiber is dietary fiber with the ability to dissolve in water. Once dissolved, this fiber forms a gel-like substance which functions to slow the movement of the food bolus through the gastrointestinal tract. Slowing down the movement provides the body with an extended period of time with which absorption of dietary nutrients can take place. If transit through the gut was too fast, you would not have a chance to retain enough of the nutrients from your meals.
Insoluble fiber is what creates the ‘bulk’ that is required to promote the movement of food through the digestive tract. If this bulk was not present, the oscillating movement of your intestines wouldn’t have anything to push against. A lack of insoluble dietary fiber is likely to cause constipation.
Why is Fiber Essential?
While it is easy to assume that other macronutrients such as carbohydrates, proteins, and fats are far more important, fiber is an essential dietary component. Fibers’ importance is often overlooked due to the fact that it is not actually absorbed.
A study that was conducted in 2011 by the National Institutes of Health  concluded that individuals who consumed a higher volume of dietary fiber over an extended period of nine years had a significantly lower risk of mortality from chronic diseases than those individuals who had a lower intake of fiber.
Fiber consumption by participants in this study varied between 10.8 grams and 25.8 grams per day in women and 12.9 and 29.4 grams per day in men. Those who lay within the top percentile and consumed the highest amounts of fiber each day were found to have a 22% lower risk of death over the study's 9-year duration than those who consumed the least amount of fiber.
This research, along with many other nutritional studies that have been conducted, provides us with reliable evidence that fiber is highly beneficial and should be included in our diets, but what exactly is the benefit that dietary fiber can provide?
- Normalises bowel movements and improved gastrointestinal health [2,3]: Arguably the most notable and important impact of fiber consumption is on the health of the gastrointestinal tract. Fiber intake promotes regular bowel movements and prevents both diarrhea and constipation. Soluble fiber that acts to slow down the transit of food, and insoluble fiber that assists in food movement and transit act in balance and unison to ensure that material travels through the digestive system at a comfortable and appropriate speed. Getting the correct amount of fiber in your diet might also act to reduce the risk of developing ulcerative colitis and hemorrhoids. There are also reports showing that dietary fiber could be effective in helping to decrease the risk of colon cancer.
- Lowers cholesterol levels [4,5]: Multiple research trials, including one conducted by the University of Maryland Medical Center, provide us with evidence to say that dietary fiber is effective in reducing the risk of heart disease. Soluble dietary fiber is shown to reduce blood cholesterol levels, therefore reducing the risk of plaque build-ups, hardening arteries, myocardial infarction, and strokes.
- Helps control blood sugar levels [6,7,8]: Consuming the correct amount of dietary fiber helps your body to maintain appropriate blood sugar levels more effectively. This can be key in both preventing the development of type 2 diabetes in at-risk groups and in proper blood sugar control in those individuals already affected by the condition. It has been found that patients with diabetes who consume a high fiber diet trend towards needing less insulin than those patients with a lower fiber intake. The reasoning behind this is dietary fiber acts to assist with the slow absorption of sugar after a meal, preventing massive spikes in blood sugar.
- Aids in healthy weight loss [9,10]: Obtaining high amounts of dietary fiber can make a significant contribution towards healthy body weight maintenance and reduction. Fiber plays a major role in producing the feeling of satiety and fullness after a eating, without adding additional calories to your meal (remember: fiber isn’t digested or absorbed by the body). This feeling of fullness stops you from overeating or eating too many of the wrong foods, and can, therefore, be effective in aiding weight loss or preventing obesity.
- Nutritional profiles: Many of the foods that are naturally high in dietary fiber are, in addition, very nutritious for other reasons. Fruit and vegetables are high in fiber and also packed full of essential vitamins, minerals, and antioxidants.
How much fiber do we need?
The recommended daily allowance of fiber is 25 grams per day for females and 30 grams per day for males. If you are consuming a 2000 calorie per day diet, it equates to 14 grams of fiber per 1000 calories consumed.
Where can you get your fiber?
Fiber is found in many of the staple foods in our diet, so it’s pretty easy to get enough of it as long as you are regularly choosing to eat the right stuff. Fruit, vegetables, beans and legumes, nuts and seed, as well as whole wheat carbohydrate sources like brown bread are great sources of dietary fiber. These foods are also all nutritious in their own right, providing you with many other important nutrients.
Foods that won’t help you when it comes to trying to get enough fiber in your diet are refined carbohydrates, such as white bread and rice, and other processed foods. Generally, if foods have been manufactured, some of the goodness has been taken out of them, and fiber is often one of the nutrients that get taken away. When grains are refined, the bran is removed from the grain, leaving the final product low in fiber content.
Fiber supplements are another option. While obtaining your fiber from whole food sources is always recommended, supplementation is always an option if you are really struggling. Some of the fiber supplements that are available include Metamucil, Citrucel, and Fibercon. Fiber supplements don’t contain any of the additional nutrients that whole foods provide you with and they often do not provide the same variety of fibers either.
Finally, there is the option to obtain your dietary fiber from fortified products such as cereals, granola bars or yogurts. The fiber that is usually used to fortify these products is Inulin or Chicory root.
Top fiber tips
Some great tips to increase the amount of fiber in your diet are:
- Choose a high-fiber breakfast: Eating a high-fiber cereal for breakfast such as plain wholewheat biscuits, plain shredded whole grain, porridge or oats is a great way to start your day off with a quick boost of fiber.
- Choose whole grains: When you go to buy your bread, pasta, rice and whatever other staple carbohydrates you find yourself consuming on a weekly basis, make an easy swap to the whole wheat or whole grain version of the product to make a huge difference to your diet's overall fiber content.
- Leave the skins on: Leaving the skin on when you eat your apple or making sure to eat the skin of your baked potato is also a super easy way of boosting the amount of fiber you’re getting from your diet. A baked potato with its skin contains approximately 2.6g of fiber in comparison to its fiber-lacking skinless counterpart.
- Legumes: Beans, peas, and legumes of all shapes and sizes are a fantastic way of getting a huge hit of dietary fiber. Even a tin of reduced-salt baked beans in tomato sauce has a whopping 9.8g of fiber per portion, so definitely don’t forget about them!
- More plant foods: Plant foods are some of the most fiber-dense food products out there. There more green, leafy roughage you can get into your diet the better – and that’s before you even consider all those extra vitamins!
The final word on fiber
Reaching the end of this article you should find yourself fully educated and thoroughly prepared to start incorporating this underrated nutrient into your diet in a more purposeful manner. The next time you head out to do your weekly shop, remember these fiber-friendly tips – you’ll thank us later.
 Park, Yikyung, et al. “Dietary fiber intake and mortality in the NIH-AARP diet and health study.” Archives of internal medicine 171.12 (2011): 1061-1068.
 Montagne, L., J. R. Pluske, and D. J. Hampson. “A review of interactions between dietary fibre and the intestinal mucosa, and their consequences on digestive health in young non-ruminant animals.” Animal feed science and technology 108.1-4 (2003): 95-117.
 Mertens, David R. “Dietary fiber components: relationship to the rate and extent of ruminal digestion.” Federation Proceedings. Vol. 36. No. 2. 1977.
 Arjmandi, Bahram H., et al. “Dietary soluble fiber and cholesterol affect serum cholesterol concentration, hepatic portal venous short-chain fatty acid concentrations and fecal sterol excretion in rats.” The Journal of Nutrition 122.2 (1992): 246-253.
 Brown, Lisa, et al. “Cholesterol-lowering effects of dietary fiber: a meta-analysis.” The American journal of clinical nutrition 69.1 (1999): 30-42.
 Giacco, Rosalba, et al. “Long-term dietary treatment with increased amounts of fiber-rich low-glycemic index natural foods improves blood glucose control and reduces the number of hypoglycemic events in type 1 diabetic patients.” Diabetes Care 23.10 (2000): 1461-1466.
 Qureshi, Asaf A., Saeed A. Sami, and Farooq A. Khan. “Effects of stabilized rice bran, its soluble and fiber fractions on blood glucose levels and serum lipid parameters in humans with diabetes mellitus Types I and II.” The Journal of nutritional biochemistry 13.3 (2002): 175-187.
 Trowell, H. C. “Dietary-fiber hypothesis of the etiology of diabetes mellitus.” Diabetes 24.8 (1975): 762-765.
 Layman, Donald K., et al. “A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women.” The Journal of Nutrition 133.2 (2003): 411-417.
 Melanson, Kathleen J., et al. “Consumption of whole-grain cereals during weight loss: effects on dietary quality, dietary fiber, magnesium, vitamin B-6, and obesity.” Journal of the American Dietetic Association 106.9 (2006): 1380-1388.
Steven has researched over 500 weight-loss programs, pills, shakes and diet plans. He has also worked with nutritionists specializing in weight loss while coaching people on how to transform their physiques and live healthy lives.