If you’ve been diagnosed with SIBO (Small Intestinal Bacterial Overgrowth), chances are you’ve been recommended a treatment plan that includes dietary modification. That makes sense – after all, we are what we eat.
But what if you’ve followed the diet, and your symptoms haven’t improved – or have even gotten worse? You’re not alone.
Many people with SIBO begin dietary protocols like the Bi-Phasic or low-FODMAP diet, hoping for relief – only to feel more restricted, more confused, and still symptomatic. Why? Because these diets, while helpful in some cases, don’t address the root causes of SIBO or the unique needs of your gut.
So when it comes to SIBO, one size does not fit all.
SIBO isn’t just about what you eat – it’s about why the overgrowth happened in the first place. Without personalisation, dietary changes can miss the mark. In some cases, they may even delay healing or create new issues, like nutrient deficiencies or increased food sensitivities.
In this article, we’ll explore why the standard SIBO diet doesn’t work for everyone, what critical factors need to be assessed before starting any protocol, and how a tailored approach can help you finally get lasting relief.
SIBO diets: A closer look
The most widely used dietary approach for SIBO is based on a low-FODMAP framework. We’ve put together a helpful guide that explains what FODMAPs are and why they matter for gut health. In short, FODMAPs are fermentable fibres that bacteria love to feed on.
FODMAPs are not inherently harmful – they’re beneficial for many people. But in SIBO, where bacteria grow where they shouldn’t, these fibres can cause more harm than good.
When bacteria overgrow in the small intestine, the usual dietary advice to eat 30-50g of fibre a day to support gut health can backfire. Instead of feeling better, you might experience bloating, gas, nausea, fatigue, and a host of other uncomfortable symptoms.
That’s why managing SIBO through diet can – and should – look different for everyone.
Why SIBO diets need to be tailored
Every gut ecosystem is unique. So is your health history, lifestyle, and symptoms. That’s why a personalised approach is essential.
Some potential benefits of dietary modification for SIBO include:
- Reducing the food sources that feed bacterial overgrowth
- Helping rebalance bacteria in both the small and large intestines
- Mitigating damage caused by bacterial overgrowth, such as damage to microvilli, destruction of brush border enzymes, pain and inflammation
- Supporting repair of the small intestinal lining
- Reducing systemic symptoms that can occur with SIBO, such as headaches, body aches, joint pain, abdominal inflammation, fatigue, brain fog, irregular bowel motions (diarrhoea or constipation), sleep quality, and much more
But what happens when these improvements don’t occur, despite dietary restrictions?
Why the Bi-phasic diet might not be working for you
Many people hit a wall with dietary restrictions for two main reasons:
- Nutritional gaps and gut diversity loss: Restrictive diets can lead to nutrient deficiencies and reduce microbial diversity in the large intestine, an essential component of gut health
- The root cause is being missed: Diet alone doesn’t fix what’s driving SIBO. And without addressing those deeper causes, symptoms often persist or return
What to know before starting a SIBO diet
Before diving into any dietary protocol, it’s essential to assess:
- Your current nutritional status (both micro and macronutrients)
- Blood sugar regulation and metabolic health
- Overall vitality and resilience
- History of eating disorders or trauma around food
- The right timing, phase, and duration for dietary changes
- Whether proper testing has confirmed SIBO or if the diet was recommended without a diagnosis
These factors should be answered before any dietary modification is recommended, and in the case of SIBO, it can be the difference between success and failure.
What the SIBO diet might miss
Here’s what many people miss: SIBO is often not the core problem – it’s a symptom of deeper dysfunction, such as impaired gut motility, structural problems, or other infections. If these underlying causes are not identified and treated, dietary changes alone are unlikely to provide lasting results. And, if you have adhesions (scar tissue), hypothyroidism, or chronic stress affecting gut movement, SIBO may persist or recur, even with strict dietary adherence. These underlying issues don’t resolve with diet alone – and may even be worsened by prolonged restriction or stress from food avoidance.
Assessment of SIBO causes should be conducted throughout the treatment protocol and incorporated into an ongoing maintenance and management plan. SIBO treatment can be very effective; however, the risk of relapse is high. Addressing causes is important in the prevention of relapse.
There’s no one-size-fits-all SIBO diet
Everyone responds differently to food. What works for one person may worsen symptoms in another. Some find common SIBO diets too restrictive; others may struggle with reactivity to “safe” foods.
That’s why customisation is key. Your diet should reflect your body’s needs, not just a protocol.
Staying restrictive for too long can backfire
Overly long restrictive phases can harm your gut in other ways – causing nutritional deficiencies and weakening microbial diversity in the large intestine.
If you remain in the restrictive phase for too long without reintroducing foods or retesting, the protocol may fail to restore gut health or resolve symptoms.
For a SIBO protocol to succeed, it’s critical to:
- Monitor nutritional status throughout
- Reintroduce foods gradually and systematically
- Retest at appropriate intervals to assess progress
Incomplete or improper food reintroduction
The reintroduction phase is just as important as the initial restriction. If rushed or skipped, symptoms may return, and true food triggers may remain unidentified.
This is where our health coaches provide valuable support: helping you pace the process, track symptoms, and build a sustainable, nourishing long-term diet.
Other gut issues or misdiagnosis
Persistent symptoms may be due to other gut conditions (e.g., fungal overgrowth, parasites, low stomach acid or inflammatory bowel disease) that require different treatments.
If only SIBO is tested and treated, but other issues are present, the diet will not resolve all symptoms.
Tailored support for lasting SIBO relief
Our approach goes beyond diet. We combine functional medicine with personalised health coaching to create a plan that addresses the why – not just the what. We focus on:
- Personalised testing and root cause analysis: We identify what’s really driving your SIBO and other symptoms, so you’re not just treating the surface
- Tailored dietary plans: We adapt your diet to your specific needs, symptoms, and tolerances, ensuring you get nutrition and gut support without unnecessary restriction
- Lifestyle and stress management: Because stress and hormonal imbalances can impair gut motility, we help you build resilience and improve overall vitality
- Guided food reintroduction: We provide health coaching support to help you systematically and safely reintroduce foods, pinpoint triggers, and develop a sustainable long-term eating plan
- Comprehensive gut health restoration: We work to rebalance your gut microbiome, repair intestinal lining, and optimise digestion beyond just reducing bacterial overgrowth
If the SIBO bi-phasic diet hasn’t worked for you, it’s not your fault. Diet alone is rarely enough, and if it’s not tailored to your unique situation, it may even make things worse.
SIBO is complex. But with the right support, from a functional medicine practitioner to uncover the root causes, and a health coach to guide you day-to-day, you can move beyond symptoms and finally feel like yourself again.
