Fiber is in plant-based foods, so if you don’t eat a lot of fresh fruits, whole grains, legumes, or nuts, you’re not getting enough fiber in your diet. Even if you do eat a vegetarian or vegan diet, it’s still possible to not get enough fiber if your diet consists of processed foods with lots of added sugar and fat (like chips or cookies) and little fiber.
Fiber is a type of carbohydrate that your body can’t digest. When you consume fiber, it passes through your stomach and intestines undigested, yet it still has an important function. It helps move food along in your digestive tract and keeps your digestive system healthy. Fiber helps keep waste moving through your system and prevents constipation. Getting more fiber may have other benefits too. Some studies show consuming more fiber helps with weight and appetite control and may lower the risk of cardiovascular disease.
Still. many Americans don’t get enough fiber in their diets. Guidelines are 25 grams per day for women and 38 grams per day for men - but most people only get about half that amount daily. But what if you’re adding more fiber to your diet and it makes you feel bloated or gassy? It’s a common problem. Fortunately, there are ways to make fiber more tolerable in your diet. Here are some reasons you get bloated when you consume fiber.
You’re Introducing Fiber into Your Diet Too Quicky
When you add fiber to your diet too fast, you could experience gas and bloating, diarrhea, nausea, or constipation. Why? You’re not giving your gut a chance to adapt to a higher fiber load. If you’re not accustomed to eating a lot of fiber, your intestinal tract may rebel.
The solution? Start by adding one serving of a high-fiber food per day. Then gradually increase the amount until you reach your goal. Doing this will give your gut and gut microbiome a chance to adapt and learn to process fiber-rich foods. Also, avoid taking fiber supplements, as they’re more likely to cause gas and bloating. Introduce fiber-rich foods slowly into your diet. Even if you’re doing something good for your health, don’t rush it!
You’re Eating Fiber-Rich Nutrition Bars
High-fiber nutrition bars are packed with fiber, more than your system can comfortably manage if you’re not accustomed to fiber. These bars often contain wheat bran or psyllium husk that can cause bloating and diarrhea until your body adapts to a higher fiber diet.
Fiber may not be the only trigger for intestinal discord in these bars either. Some nutrition bars are sweetened with sugar alcohols, also known to cause bloating, gas, and tummy cramping. If you see ingredients like maltitol, erythritol, xylitol, mannitol, or sorbitol, the bar contains sugar alcohols, and you could experience digestive issues from both the fiber and sugar alcohols.
You’re Not Drinking Enough Water
Water helps move fiber through your intestinal tract faster, so you’re less likely to experience bloating. Make sure you’re causing enough water in your diet when you increase your fiber intake. Also, avoid drinking liquids with a straw since swallowed air can cause gas and bloating too.
You’re Not Optimizing the Ratio of Soluble to Insoluble Fiber
Soluble fiber is more likely to cause gas and bloating than insoluble fiber. What’s the difference? Insoluble fibers do not dissolve in water, but they keep your stool soft by absorbing water as they pass through your digestive tract. This helps to prevent constipation and hemorrhoids. Foods high in insoluble fiber include wheat bran, oat bran, nuts, legumes, and potatoes.
Soluble fiber dissolves in water and includes nuts, seeds, peas, lentils, oat bran, fruits, and vegetables. Soluble fiber is of benefit because it can lower your cholesterol level and help with blood sugar control. As you can see, many fiber sources contain both soluble and insoluble fiber, but you may experience less bloating if you increase the ratio of insoluble to soluble fiber, at least until your gut adapts to more soluble fiber.
You Have Undiagnosed Digestive Issues
If you add more fiber to your diet and you continue to have gas and bloating after a few weeks, you could have an undiagnosed intestinal condition like irritable bowel syndrome. (IBS), a gastrointestinal condition that affects the colon. Symptoms include abdominal pain, bloating, constipation, and/or diarrhea.
Certain foods can trigger symptoms in people with IBS, including fructose, lactose, and FODMAPs. FODMAPs are short-chain carbohydrates that are poorly absorbed in the small intestine. They include lactose (found in dairy), fructose (found in fruits), fructans (found in wheat), and galactooligosaccharides (GOS), which are in legumes such as chickpeas. If you increase the fiber content of your diet, you’ll naturally consume more FODMAPs, which can worsen IBS symptoms.
Also, consuming more gluten-containing fiber sources can cause gas, bloating, and abdominal cramping if you have Celiac disease, an autoimmune disorder that causes the body to attack its own tissue when it encounters gluten. Gluten is a protein found in grains like wheat, rye, and barley, which are high-fiber foods.
Celiac disease is caused by an immune response to gluten - a protein found in wheat, barley, and rye - that damages the lining of the small intestine. The damage prevents the absorption of nutrients from food. Gluten is found in most grains except for rice and corn.
To prevent symptoms from occurring or worsening, people with celiac disease must avoid all foods containing gluten, even tiny amounts. Some people don’t have celiac disease but are still gluten intolerant. If you’re gluten intolerant, you test negative for celiac disease but still develop intestinal symptoms if you consume gluten-containing grains. Therefore, if you have persistent digestive symptoms when you consume more fiber and it doesn’t resolve, talk to your physician. Also, keep a food diary and see which foods aggravate the symptoms.
The Bottom Line
Now you know why fiber can cause bloating. The key to preventing this unpleasant side effect is to introduce fiber slowly into your diet, drink more water, and consume more insoluble fiber relative to soluble fiber.
References:
- “Why Is Fiber Good for You? The Crunchy Truth – Healthline.” 15 Sept. 2021, healthline.com/nutrition/why-is-fiber-good-for-you.
- “Dietary fiber: Essential for a healthy diet – Mayo Clinic.” 06 Jan. 2021, mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/fiber/art-20043983.
- McRorie JW Jr. Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 2: What to Look for and How to Recommend an Effective Fiber Therapy. Nutr Today. 2015 Mar;50(2):90-97. doi: 10.1097/NT.0000000000000089. PMID: 25972619; PMCID: PMC4415970.