How We Helped a Client Overcome SIBO and Fructose Intolerance: A Real Success Story

Written by Karly Raven, BHSc - Naturopath and SIBO Specialist, Nourished Gut Clinic
Last updated: August 2026

Note: Client details have been shared with permission. The name used is a pseudonym and identifying details have been changed.

Struggling with SIBO and fructose malabsorption? You are not alone.

Imagine dealing with daily bloating, unpredictable bowel movements, and discomfort after every meal. For people living with Small Intestinal Bacterial Overgrowth (SIBO) alongside fructose malabsorption, that is the everyday reality.

In this case study I want to show what a properly sequenced approach looks like, including the part most write-ups leave out: the first round did not clear it, and what we did next.

Jump to a section

1. What are SIBO and fructose malabsorption?
2. Presentation
3. Testing
4. Root causes
5. The treatment plan
6. Results
7. Maintenance
8. Frequently asked questions

What are SIBO and fructose malabsorption?

SIBO occurs when the microbial community of the small intestine loses its balance, producing bloating, gas and irregular bowel movements. Fructose malabsorption means fructose is not fully absorbed, so it travels on and gets fermented, causing much the same symptoms by the same mechanism.

The important distinction is between primary fructose malabsorption, where absorptive capacity is limited in its own right, and secondary, where the malabsorption is a consequence of the overgrowth and improves once it is treated. That distinction determines whether someone is managing something long term or reversing something temporary. SIBO breath testing explains how we separate the two.

Presentation

This client came to me after a period of extended travel that left her with significant gut symptoms, including an episode of food poisoning while she was away.

• Symptoms. End of day bloating, bowel movements swinging between diarrhoea and constipation, and a clear worsening through the second half of her menstrual cycle.
• Lifestyle. An otherwise low stress life, with one significant ongoing caring responsibility.
• History. Regular antibiotic use, one to two courses annually over a number of years, and a period of oral contraceptive use in her twenties.

Testing

• Mixed hydrogen and methane SIBO. Confirmed on breath testing. Mixed pictures like this are common and they change the sequencing, because methane is usually the limiting factor.
• Secondary fructose malabsorption. Identified on fructose substrate testing, and importantly flagged as secondary rather than primary, which meant it was likely to improve with treatment rather than requiring lifelong avoidance.
• Imaging. A CT scan showed mild distal fluid and gas in the small bowel.
• Colonoscopy. A polyp was removed, with no other abnormalities found.
• Stool PCR. No active pathogens detected.

Root causes

• Impaired motility, most likely post-infectious following the food poisoning episode. This is the single most common driver I see in recurrent cases.
• Environmental exposure during travel, which may have contributed.
• Repeated antibiotic courses, which had depleted microbiome diversity over years.
• Family history of autoimmune conditions.

The treatment plan

She arrived having already completed a three week biphasic diet and one round of SIBO treatment with another practitioner, without lasting result. That is a very typical starting point for the people I work with.

We tailored treatment to address the overgrowth, the fructose malabsorption and the reason both had developed.

• Transitioned her onto the SIBO Restore Diet for a staged dietary plan with a defined end point, rather than open-ended restriction.
• Introduced supportive additions including adequate hydration, flaxseeds, ginger and kiwifruit to address the constipation side of her mixed pattern.
• Adjusted her antimicrobial formula to a gentler approach given her depleted microbiome, and matched the probiotic strain to her phenotype and treatment phase.

Results

After the first treatment phase, repeat breath testing showed a significant reduction but not full clearance. This is the point where a lot of people give up, or where a practitioner declares victory on symptoms alone. We retested and kept going.

The second round involved:

• Adjusted herbal formulas, with dosages increased slowly to target what remained.
• Gut lining support, adding immunoglobulin powder to support the mucosal barrier.

After five more weeks, follow-up breath testing confirmed she was clear.

Maintenance

Clearing the overgrowth was the halfway point, not the finish line. Without a maintenance phase, relapse is the predictable outcome.

• Progressed to Stage 3 of the SIBO Restore Diet, where prebiotic introduction begins.
• Reintroduced foods gradually, including fructose containing foods, since her malabsorption was secondary and tolerance was expected to return.
• Continued microbiome and motility support to hold the result.

In her words

"I joined the Nourished Gut Program at the beginning of my SIBO journey. After receiving a positive diagnosis from another naturopath, I was determined to work with the best team to achieve the quickest results possible. I committed to giving 110% effort to become SIBO-free swiftly.

The program's thoroughness and the personalised support have been exceptional. By following the guidance diligently, I've achieved significant results. Compared to another program I tried, the SIBO Restore Diet offers delicious Australian-style meals and provides clear guidance even after becoming SIBO-free and reintroducing foods. I highly recommend this program to anyone dealing with SIBO."

Karen, Nourished Gut Program client

Frequently Asked Questions

Why did the first round of treatment not clear it?

Mixed hydrogen and methane cases usually need more than one round, because methanogens are archaea rather than bacteria and are less responsive to standard antimicrobials. A partial reduction after round one is a normal and expected result, not a failure. What matters is retesting rather than guessing, then adjusting the formula and continuing rather than starting over.

Will my fructose intolerance go away if I treat SIBO?

If it is secondary to the overgrowth, usually yes. That is why testing with a fructose substrate matters. Secondary malabsorption improves as the small intestine recovers, and fructose containing foods can be reintroduced gradually. Primary fructose malabsorption is a different situation and is managed by matching intake to capacity long term.

How long did this take?

Two rounds of treatment, with the second running a further five weeks, plus the maintenance and reintroduction phase afterwards. Six months is a realistic timeframe for a mixed picture with a post-infectious driver. Anyone promising resolution in a few weeks is not describing the same condition.

Are these results typical?

This is one client's experience and outcomes vary. Results depend heavily on the root cause. Where the driver is reversible, full clearance is a realistic goal. Where it is structural or the post-infectious damage is more established, good long term management is the honest expectation. I would rather set that out at the first consultation than the fourth.

Ready to take charge of your gut health?

This case shows what a phased, tested, properly sequenced approach looks like, including the part where the first round does not finish the job.

If you want a practical starting point this week, the free 3-Day Bloat Fix is a short plan you can begin straight away.

The Nourished Gut Program is our six month process for exactly this kind of case. It is application only and we take five new clients each month. Book a free Digestive Strategy Session and we will tell you honestly whether it suits your situation.

Disclaimer

This case study describes one client's journey and outcomes. Individual results vary. Always consult a qualified health practitioner before starting new treatments or making changes to your health regimen.

Karly Raven, BHSc is a naturopath, microbiome restoration specialist, and SIBO expert. She is the founder of the Nourished Gut Clinic and creator of the Feed Forward methodology and the SIBO Restore Diet. Karly works with people with IBS, SIBO, IBD and chronic gut conditions, and mentors health practitioners through karlyraven.com.

This blog is for educational purposes only and does not constitute medical advice. Please consult a qualified health practitioner before making changes to your treatment plan.