Why Would You Be Put on a Low Fibre Diet?

January 2, 2026 •

3 min read

According to the National Institutes of Health, a low-fibre diet is often prescribed temporarily to reduce bowel irritation and allow the digestive system to rest and heal. It is crucial for patients to understand why they are put on a low fibre diet and to follow their healthcare provider's instructions carefully.

Quick Summary

A low-fibre diet is prescribed for various medical reasons, including managing flare-ups of inflammatory bowel disease, preparing for a colonoscopy, and recovering from bowel surgery to reduce stress on the digestive tract.

Key Points

Medical necessity: A low-fibre diet is a temporary, doctor-recommended measure for specific health conditions, not a long-term lifestyle choice.
Colonoscopy prep: It is essential for thoroughly cleansing the bowel before a colonoscopy to ensure clear visibility.
IBD and diverticulitis: It helps manage symptoms during inflammatory flare-ups of conditions like Crohn's disease, ulcerative colitis, and diverticulitis.
Surgical recovery: Post-bowel surgery, it minimizes stool bulk to allow the surgical site to heal properly.
Bowel blockages: For those with bowel narrowing, it reduces the risk of obstruction by limiting indigestible food particles.
Gradual reintroduction: Fibre should be slowly and carefully added back into the diet once the medical issue has resolved to prevent discomfort.

Understanding the Rationale Behind a Low Fibre Diet

While a high-fibre diet is generally recommended for overall health, there are specific medical circumstances where a low-fibre diet becomes a necessary, albeit temporary, dietary modification. This diet, also known as a low-residue diet, reduces the amount of indigestible food and stool that passes through the large intestine. It is not a permanent solution but a tool used to manage symptoms and allow the digestive tract to heal or to be prepared for certain procedures.

Preparing for Medical Procedures

A common reason for a short-term low-fibre diet is preparing for a colonoscopy. A clean bowel is necessary for the doctor to clearly view the colon's lining. Dietary restrictions start days before, reducing fibre intake until only clear liquids are consumed. Avoiding high-fibre foods like whole grains, nuts, and seeds minimizes residue.

Managing Inflammatory Bowel Conditions

For individuals with inflammatory bowel diseases (IBD) like Crohn's disease or ulcerative colitis, a low-fibre diet can help manage symptoms during a flare-up. During these times, the gut lining is inflamed, and high amounts of coarse fibre can worsen pain and diarrhoea. Reducing fibre puts less stress on the digestive system.

Recovering from Bowel Surgery

Patients recovering from intestinal surgery are often on a low-fibre diet. The digestive system needs time to heal without bulky stools. Fibre is gradually reintroduced under medical supervision, which helps prevent complications.

Dealing with Diverticulitis

Diverticulitis is inflammation of pouches in the colon. While a high-fibre diet prevents it, a low-fibre diet is prescribed during a flare-up. Reducing fibre lets inflamed pouches heal, easing pain. While nuts and seeds were thought to cause flare-ups, they are now considered safe in remission, but fibre is restricted during an active episode.

Other Specific Medical Needs

A low-fibre diet may also be recommended for:

Bowel Obstructions: To reduce the risk of a complete blockage if the bowel is narrowed.
Radiation Therapy: To minimize gastrointestinal issues during pelvic radiation treatment.
Gastroparesis: To help manage poor stomach muscle function.

High Fibre vs. Low Fibre Diet: A Comparison


Feature	High Fibre Diet	Low Fibre Diet
Purpose	Promotes healthy digestion, regular bowel movements, and overall gut health	Reduces strain on the digestive system, manages symptoms, and facilitates healing
Key Foods	Whole grains, raw fruits & vegetables, legumes, nuts, seeds	Refined grains (white bread, white rice), cooked vegetables without skin/seeds, soft fruits (bananas, melon), tender meats, dairy
Stool Volume	Increases bulk and softens stool	Decreases bulk and reduces the amount of residue
Duration	Recommended for long-term health for most people	Typically a temporary measure for specific medical issues
Medical Conditions	Used for prevention (e.g., diverticulosis), heart health, weight management	Used for acute conditions (e.g., diverticulitis flare-ups), surgery prep, bowel blockages

Conclusion

While high-fibre is key for health, a low-fibre diet addresses specific medical needs, mainly digestive issues. It's a tool for preparing for procedures, managing acute IBD and diverticulitis symptoms, and aiding post-surgery recovery. It's usually temporary, and fibre should be slowly added back under a doctor's guidance. A long-term low-fibre diet can cause issues like constipation and gut microbiome imbalance. A personalized approach is best.

For more information on dietary management of digestive health, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is a reliable resource. NIDDK

Frequently Asked Questions

While the terms are often used interchangeably, a low-residue diet is typically a more restrictive version of a low-fibre diet. It limits foods that produce stool residue, which can include both fibre-rich foods and some dairy products, even if they don't contain fibre.

The duration depends on the specific medical reason. For a colonoscopy, it's a few days. For IBD flare-ups or surgery recovery, it may be longer, typically a few weeks. Your doctor or dietitian will provide a specific timeline.

No, nuts and seeds are generally high in fibre and should be avoided on a low-fibre diet. During a diverticulitis flare-up, they should be strictly avoided. After recovery, they may be slowly reintroduced.

The most common side effect is constipation, as fibre is essential for promoting regular bowel movements. It's crucial to stay hydrated by drinking plenty of water to help counteract this.

Allowed foods typically include refined white bread, white rice, cooked vegetables without skin or seeds, ripe fruit without skin, tender meats, and plain dairy products.

No, a low-fibre diet is not intended for weight loss and may make it more difficult to manage weight. High-fibre foods are known to promote a feeling of fullness, which aids in weight control.

If you're on a restricted diet for a procedure like a colonoscopy, inform your doctor, as it may affect the test's clarity. For managing a medical condition, a small mistake may not cause major issues, but you should monitor your symptoms and avoid it going forward.