The Changing View of Fiber: Why It’s More Important Than You Think

fiber foods

Ask most health experts and they’ll tell you that most Americans get only half the amount of fiber their body needs for optimal health. Fiber has come into focus in the past few decades, but it isn’t a modern dietary phenomenon. In fact, Hippocrates, the Father of Medicine, advocated that people consume fiber for intestinal health from a variety of plant-based sources in 4 B.C. You only get fiber from plant-based foods. Meat and dairy contain vitamins and minerals, but they lack dietary fiber.

Fiber isn’t a single entity. In fact, there are two main types of fiber: soluble and insoluble. Soluble fiber gets most of the attention since it’s the form linked with most of the health benefits attributed to fiber. Studies suggest that consuming soluble fiber helps with blood glucose control, increases satiety, and may lower the risk of cardiovascular disease. Insoluble fiber still has benefits though. By grabbing on to water like a sponge in the digestive tract, it softens the stool and helps food to move more easily through the lower digestive tract and out of the body. So, insoluble fiber helps some people manage constipation.

Decades ago, fiber didn’t get a lot of fanfare. In fact, experts believed it was only effective for cleaning out the intestines and relieving constipation. But modern research now shows that fiber plays an important role that extends beyond intestinal housekeeping. It was in the 1970s that the health care community awakened to the full benefits of fiber. The stimulus was researched by Dennis Burkett who studied the colon health of British soldiers in Uganda, who ate a fiber-rich diet and compared it to other British soldiers who ate a low-fiber diet. They discovered that soldiers who ate the fiber-rich diet experienced faster movement of food through their intestinal tract and had a lower risk of certain forms of cancer and diseases of the digestive tract.

Such positive findings led to further studies looking at the role fiber plays in health. According to epidemiological studies, eating a higher fiber diet may lower the risk of health problems, including cardiovascular disease, metabolic syndrome, and type 2 diabetes. But how can you explain the benefits of fiber?

When you eat fiber-rich food, the fiber attracts water and forms a jelly-like mass. This jelly-like material slows the rate of movement out of the stomach. As a result, you feel fuller and more satisfied. Plus, the slowing of absorption reduces the rise in blood sugar you get after a meal. In addition, fiber binds to bile acids in the digestive tract, so that your body has to use cholesterol to make more bile. Therefore, fiber can lower your cholesterol level. When you eat a fiber-rich diet, you also absorb less dietary fat from the food you eat. Therefore, fiber may help with weight control.

Another benefit of fiber that you hear less about is its role in keeping the lining of your colon healthy. Fermentable fiber is a type of soluble fiber that bacteria can consume and ferment. When gut bacteria ferment fiber, they produce short-chain fatty acids, like butyric acid. Studies show that colon cells use butyric acid as an energy source. Some animal studies reveal this weak acid reduces inflammation and may calm the symptoms of irritable bowel and, possibly, lower the risk of colon cancer.

As you can see, dietary fiber may have a variety of beneficial roles in the human body that extend beyond the intestinal clean-up role. Are you getting enough in your diet? Most folks are not.

Sources of Dietary Fiber

By adding more plant-based foods to your plate, you’ll naturally boost the fiber content of your diet. To up the soluble fiber content of your diet, consume more beans, peas, oats, citrus fruit, berries, and apples. When you munch on these foods, the soluble fiber binds to cholesterol so more can be flushed out of your body and not enter your bloodstream. Plus, soluble fiber slows glucose absorption, which helps with blood sugar control.

To add more insoluble fiber to the table, focus on legumes, seeds, nuts, whole grains, and root vegetables. All fruits and vegetables have a mixture of soluble and insoluble fiber, so you can’t go wrong by simply eating more plants.

Are There Downsides of Consuming Fiber?

As with most foods, too much can be detrimental. If you introduce more fiber into your diet too fast, you may develop gastrointestinal symptoms such as bloating and flatulence. When you switch from a diet low in fiber to a fiber-rich diet, your body needs time to adjust. Therefore, it’s safest to gradually add more fiber to your plate over a few weeks. When you consume more fiber, drink more water to compensate. Over time, aim for 25 to 30 milligrams of fiber daily.

Compounds called phytates in fiber also reduce mineral absorption. If you eat lots of mineral-rich whole foods, it’s doubtful that the fiber will reduce your mineral status, but it’s something to think about.

The Bottom Line

Most people don’t get enough fiber in their diet, but that doesn’t have to be you! You can’t go wrong by adding more fiber-rich nuts, seeds, fruits, vegetables, whole grains, and legumes to your diet. But if you aren’t used to eating a lot of fiber, take it slow to avoid digestive upset. Along with the fiber, you’ll get vitamins, minerals, and phytonutrients too.



  • com. “The Health Benefits of Fiber: Fiber’s Health Benefits”
  • Food Processing Magazine. August 2008. “The New View of Fiber”
  • Medical News Today. “Soluble and insoluble fiber: What is the difference?”
  • Harvard T.H. Chan School of Public Health. “Fiber”
  • Pereira MA, O’Reilly E, Augustsson K, et al. Dietary fiber and risk of coronary heart disease: a pooled analysis of cohort studies. Arch Intern Med. 2004;164:370-6.
  • Nutr Res. 2013 Oct;33(10):811-6. doi: 10.1016/j.nutres.2013.05.016. Epub 2013 Jul 26.
  • Zhang J, Yi M, Zha L, et al. Sodium Butyrate Induces Endoplasmic Reticulum Stress and Autophagy in Colorectal Cells: Implications for Apoptosis. PLoS One. 2016;11(1):e0147218. Published 2016 Jan 19. doi:10.1371/journal.pone.0147218.
  • Medical News Today. “Soluble and insoluble fiber: What is the difference?”


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