IBS-C and Fibre: Why It’s Not as Simple as “Just Eat More Fibre”

Written by: Dr. Rachael Lovink, ND

Updated: May 6th, 2025

If you have Irritable Bowel Syndrome with Constipation (IBS-C) and are following a recommended IBS-C diet but still feel bloated, backed up, or frustrated—you’re not alone. You’ve probably heard that more fibre is the solution—but for many people with IBS-C, it’s not that simple. This article breaks down why fibre doesn’t always help right away, what to focus on first, and how to reintroduce fibre in a way that works with your body—not against it.

Why Fibre Doesn’t Always Work on an IBS-C Diet

Fibre is an essential part of any IBS-C diet. However, if stool isn’t moving through your colon efficiently, adding fibre can actually make symptoms such as bloating & gas worse! Think of your digestive system like a conveyor belt—if it’s not moving, fibre just adds to the backup.

Step 1: Support Gut Motility First

Before you increase fibre, get things moving with these habits:

A Morning Routine to Support Motility:
- Wake at the same time each day and eat within an hour.
- Drink a warm beverage in the morning (e.g., tea or coffee).
- Have a calm, fibre-containing breakfast and relax afterwards.
- Sit on the toilet 15–20 minutes after eating and take deep breaths.
Eat a Regular Intervals: Aim to eat every 3–4 hours to help regulate gut motility.
Hydration: Stay hydrated—aim for 2–2.5L of water daily.
Daily gentle movement: walking is an excellent way to help stimulate your bowels & to release trapped gas, which may be contributing to bloating.
Try gentle stimulators: kiwi, ginger tea, warm liquids, or a small amount of fat like olive oil.

If you’re very backed up, these strategies might not be enough (but are still essential in the long-run). In this case, strategic laxative support—when supervised by a practitioner—can help to clear out stool and allow for the lifestyle factors mentioned above to work their magic.

Step 2: Add Fibre Slowly (Once You’re Bowels Are Moving)

Once motility improves and you’re having more regular bowel movements, gradually build fibre back in. Focus on soluble fibre first, which softens stool and supports beneficial gut bacteria. Here are some examples:

Chia seeds or soaked flaxseed
Cooked oats or lentils
Cooked carrots or squash
Ripe banana & kiwi fruit
Psyllium husk (start with ½ tsp and increase slowly)
Partially hydrolyzed guar gum (PHGG)

Still Struggling with Fibre?

If you’re still bloated or uncomfortable, pause and reassess. Your progress may be limited due to one of several underlying factors that need to be addressed:

Visceral hypersensitivity (sensitive gut nerves)
Chronic stress or not enough “rest & digest” time
Low calorie intake
Irregular meal patterns
Pelvic floor dysfunction (trouble fully emptying bowels)

Work with a healthcare provider to address these barriers and create a personalized plan. You may benefit from using a gentle fibre supplement like PHGG while working on the above.

The Big Picture in IBS-C

Before we wrap up, it’s important to recognize that fibre is just one part of the picture. Long-term success with IBS-C isn’t about quick fixes—it requires a personalized plan that supports gut-brain communication and addresses your unique needs. That means combining dietary strategies with lifestyle shifts, nervous system regulation, and sometimes even medication. By building a strong foundation first—then introducing fibre slowly and strategically—you can create lasting progress instead of repeated setbacks.

Final Tips for Long-Term Fibre Success

Rotate your fibres—variety feeds different gut bacteria.
Increase slowly—add 3–5g per week.
Stay active—daily gentle movement helps bowel regularity.
Be patient—fibre is part of a long-term strategy, not a quick fix.

References

Black, C. J., Burr, N. E., Camilleri, M., Quigley, E. M. M., Moayyedi, P., & Ford, A. C. (2021). Efficacy of pharmacological therapies in irritable bowel syndrome with constipation: A systematic review and network meta-analysis. Gut, 70(6), 1051–1059. https://doi.org/10.1136/gutjnl-2020-322163

Canadian Society of Intestinal Research. (2023). IBS-C and fibre: Why it matters. https://badgut.org/information-centre/a-z-digestive-topics/ibs/

National Institute for Health and Care Excellence. (2021). Irritable bowel syndrome in adults: Diagnosis and management. https://www.nice.org.uk/guidance/cg61

National Institute of Diabetes and Digestive and Kidney Diseases. (2022). Treatment for constipation. https://www.niddk.nih.gov/health-information/digestive-diseases/constipation/treatment

Rej, A., & Aziz, Q. (2020). Psychological and behavioural therapies in irritable bowel syndrome. Journal of Gastroenterology and Hepatology, 35(1), 31–38. https://doi.org/10.1111/jgh.14911