What is fiber exactly? Fiber is a carbohydrate derived from plant foods that the body cannot digest. Most carbohydrates are broken down into sugar. However, fiber is not broken down in the same way, and actually passes through the body undigested. Fiber helps regulate blood sugar levels, helps with weight control by keeping you more full/satisfied for longer, and supports digestive health. According to Dietary Guidelines issued by the USDA, the minimum daily fiber intake should be at least 14 grams for every 1,000 calories consumed.
There are two types of dietary fiber. There is soluble fiber, which dissolves in water and helps control glucose levels and blood cholesterol. Insoluble fiber, on the other hand, does not dissolve in water and helps move food through the GI system and supports regularity and prevents constipation. However, some people are more sensitive to fiber than others and may not experience these benefits.
People with inflammatory issues or digestive ailments, such as irritable bowel syndrome, or Crohn’s disease may find that fiber actually aggravates their existing symptoms. Even if you don’t have gut inflammation issues, consuming too much fiber can cause gas, bloating and digestive distress. If you tend to have a more sensitive gut, you could be less tolerant to insoluble fiber. Insoluble fiber scrubs the colon and adds bulk to the stool, which helps decrease constipation. However, if your insides are irritated, it can worsen symptoms such as gas, cramping and diarrhea. It’s best to stick to vegetables that are higher in soluble fiber, which may be easier on the GI tract.
For the average person, insoluble fiber works for constipation by increasing “roughage” or biomass in the stool, and it may create mechanical stimulation in the bowel, causing it to trigger motility. This can help ease constipation, but in those with abnormalities in gut motility and overly sensitive systems characteristic of IBS, insoluble fiber can make symptoms worse. Soluble fiber does not have the same effect, and can bring relief especially in people with IBS-C. Ulcerative colitis usually impacts the large intestine making you extremely sensitive to the scrubbing and bulking effects of insoluble fiber. A doctor might suggest you stick to a low-residue fiber diet, which avoids insoluble fiber foods and have you stick to easily digestible options.
A healthy normal functioning gut can become sensitive to fiber by aggressive increases in fiber consumption. Adding too much too fast can cause constipation, bloating, and cramps. The body needs an adjustment period with smaller increases every 3-4 days to build up a tolerance. Adding in sweet potato instead of white rice, or an apple each day can help build up your tolerance slowly without unwanted side effects. It is also important to increase water intake with fiber to prevent dehydration and constipation. Fiber acts as a sponge and needs enough water to efficiently pass through the GI tract.
Everyone is different in what their body can handle for fiber intake, it may take some trial and error to find a happy medium for optimal fiber levels that support a healthy well functioning GI system.