Fibre and IBD: Should we avoid it or include it?
One of the most common questions I hear in clinic is whether people with Crohn's Disease or Ulcerative Colitis should avoid fibre.
It's easy to understand why there's so much confusion. For many years, people with IBD were routinely told to follow a low fibre or low residue diet, particularly during a flare. However, this was based on theory rather than evidence; the theory that the only role of fibre was to make us poo. However, we now know that fibres’ role is so much more exciting and intricate than that, in fact, fibre is vital for gut health and overall health, and avoiding it could actually have a negative effect on IBD.
As a result, the advice has changed completely. It is now encouraged that people with IBD include fibre in their diet and emerging research suggests that doing so may prolong periods of remission in IBD.
Before we continue lets just clarify more about fibre.
What is fibre?
Dietary fibre is a type of carbohydrate and the part of plants that is not digested by us in our small intestine, unlike other carbohydrates like starch and sugars, so reaches the large intestine (colon) or J-Pouch.
Where is fibre found?
Fruit and vegetables
Wholegrains – brown rice, oats, buckwheat, millet, amaranth, quinoa, teff, barley, rye, wholewheat pasta, wholegrain bread.
Legumes (beans, peas, pulses, lentils)
Nuts and seeds
Are all fibres the same?
The short answer is no.
Different types of fibre do different things as they pass through our bowels which we can often use to our advantage, such as, to help us manage symptoms.
For example, some fibres absorb water and help to reduce both diarrhoea and constipation. Others add bulk to our stools and help keep the bowels moving and prevent constipation. Some are fermented by our gut microbes producing compounds which help reduce inflammation in our bowels, support the lining of our gut and overall help to keep out gut a healthy place.
So, why can fibre feel like it makes symptoms worse?
If you've ever noticed that salads, vegetable skins or wholegrains make your symptoms worse during a flare, you are not imagining it.
When our bowel is inflamed, certain high-fibre foods can be more difficult to tolerate. In these situations, reducing, breaking down or softening rough textured fibre may help improve our symptoms and tolerance to fibre. This adaption of fibre ensures we can still include the fibres we need to support bowel movements, feed our gut microbes and enable us to have a balanced diet to support us to get better, but all whilst reducing symptoms.
Many people continue to tolerate softer textured sources of fibre during a flare, including (but not limited to):
Porridge oats
Peeled fruit
Well-cooked vegetables
Soups and smoothies
Changing the texture of a food can make a huge difference – for example, rather than whole peanuts we can include smooth peanut butter. Here we are not removing fibre, we are adapting it and its rough texture meaning we can still enjoy it.
So, the whole mantra in a flare is adapt not remove when it comes to fibre.
Should you increase your fibre intake?
If you do not have a stricture or other complication, there's usually no reason to be avoiding fibre. In fact, including a wide variety of fibre-containing foods may have a positive effect in IBD.
If you have been eating very little fibre for a while, it's important to increase it gradually though. A sudden increase can lead to bloating, wind or abdominal discomfort simply because your gut and its microbes need time to adapt.
Remember that fibre tolerance is highly individual. There isn't one perfect amount or one perfect way of eating for everyone with IBD. The goal is to find the types, textures and amounts of fibre that work for you while supporting your symptoms and long-term health.
I talk through all of this in much more detail including strategies to safely and effectively increase fibre in my What to Eat in a Flare courses and I do this 1:1 with patients in my clinic too.
Key takeaways
Fibre plays an important role in supporting the gut microbiome and overall gut health.
Unless you have been advised otherwise by your healthcare team due to having a stricture or other issue, avoiding fibre long term is rarely necessary.
Not all fibre behaves the same in the gut.
During a flare, adapting (not removing) fibre and focusing on the type and texture of fibre may improve symptoms.
If you're increasing your fibre intake, do so gradually to avoid symptoms.
Diet is a vital piece of the puzzle in IBD care, but there is rarely a one-size-fits-all approach. If you are unsure what to do about fibre, feel fearful of introducing it and need support, working with an IBD specialist Nutritionist, like me, can help you make a plan, build confidence, and a way of eating that works for you, your symptoms and your IBD.
References
Loy L, Petronio L, Marcozzi G, Bezzio C, Armuzzi A. Dietary Fiber in Inflammatory Bowel Disease: Are We Ready to Change the Paradigm? Nutrients. 2024 Apr 10;16(8):1108. doi: 10.3390/nu16081108. PMID: 38674799; PMCID: PMC11053563 - https://pmc.ncbi.nlm.nih.gov/articles/PMC11053563/#sec8-nutrients-16-01108
Limsrivilai J, Sathirawich P, Sattayalertyanyong O, Pramyothin P, Thaipisuttikul I, Pausawasdi N, Charatcharoenwitthaya P, Sarasak R, Nitayanon P, Phaophu P, Subdee N, Manatsathit S. Increased Fiber Intake Enhances Clostridia Bacteria and Reduces Clinical Relapse in Patients With Clinically Quiescent Inflammatory Bowel Disease: A Prospective Longitudinal Study. JGH Open. 2025 Jul 21;9(7):e70219. doi: 10.1002/jgh3.70219. PMID: 40697428; PMCID: PMC12280044
Naik, R.G.; Purcell, S.A.; Gold, S.L.; Christiansen, V.; D’Aloisio, L.D.; Raman, M.; Haskey, N. From Evidence to Practice: A Narrative Framework for Integrating the Mediterranean Diet into Inflammatory Bowel Disease Management. Nutrients 2025, 17, 470. https://doi.org/10.3390/nu17030470