SIBO: Looking Beyond Elimination Diets

If you’ve been struggling with bloating, excessive gas, abdominal discomfort, constipation, diarrhoea, unexplained digestive symptoms after eating, or feeling like you `look like you are pregnant’ by the end a normal day of eating, you may have come across the term SIBO, or Small Intestinal Bacterial Overgrowth.

SIBO is increasingly recognised as an important contributor to digestive symptoms, yet many people—particularly here in Germany—are still given advice that focuses solely on avoiding certain foods rather than addressing the underlying cause. While dietary changes can certainly provide temporary symptom relief, they are rarely enough to resolve the condition on their own. They often come back. And linger off and on for many years until they are properly treated.

What is SIBO?

The small intestine naturally contains relatively low levels of bacteria compared with the large intestine. In SIBO, bacteria that normally belong in the large intestine begin to overgrow in the small intestine, where they ferment carbohydrates before they can be properly absorbed. This fermentation produces gases such as hydrogen and methane, which can lead to symptoms including:

• Bloating and abdominal distension

• Excessive gas

• Abdominal pain or discomfort

• Diarrhoea, constipation, or alternating bowel habits

• Food intolerances

• Fatigue and brain fog

• Nutrient deficiencies in more persistent cases

What I normally see as a Functional Medicine Practitioner here in Germany is a ‘diagnosis` of lactose or fruit glucose intolerance (based on a breath test) and then the treatment offered is usually an elimination diet (called a low FODMAP diet). While eliminating certain fermentable carbohydrates may make you feel better for a minute in the short term, it it important to understand that SIBO is not simply a food intolerance—it’s an imbalance in the location and number of bacteria within the digestive tract.

How is SIBO Diagnosed?

The most widely used diagnostic tool is a breath test, which measures hydrogen and methane gases produced after consuming a sugar solution such as lactulose or glucose. Elevated levels of these gases suggest bacterial fermentation occurring within the small intestine. While breath testing isn’t perfect, when combined with a thorough clinical history it can provide valuable information about the type of bacterial overgrowth present and help guide treatment.As part of my practice, I order and interpret SIBO breath testing and integrate the results with a detailed assessment of your health history and digestive function to develop an individualised treatment plan.

How Conventional Medicine Typically Treats SIBO

Awareness of SIBO has improved significantly in recent years. In many countries, gastroenterologists will diagnose SIBO using breath testing and commonly prescribe antibiotics such as rifaximin, sometimes in combination with other medications depending on the type of gas produced. For some people this approach can be helpful, particularly when used appropriately. However, recurrence rates remain relatively high because the bacterial overgrowth itself is often only part of the story. If the underlying factors that allowed the bacteria to overgrow are not addressed, symptoms often return.

What I Frequently See in Germany

Many of my clients arrive after being told they have a lactose intolerance or fructose malabsorption following breath testing. They are advised to avoid lactose, fruit sugar, and often to follow a low FODMAP diet indefinitely. While reducing these foods can temporarily decrease symptoms because they reduce the amount of fermentable carbohydrate available to the bacteria, this approach has significant limitations. Rather than addressing the overgrowth itself, the bacteria remain, and the strategy merely temporarily removed their food source. Symptoms often improve while the diet is being followed, but many people find that as soon as they reintroduce foods, the bloating and discomfort return because the underlying imbalance has never been corrected.

Why Long-Term Restrictive Diets Can Become Problematic

The low FODMAP diet was designed as a short-term therapeutic intervention—not a lifelong eating plan. When I have clients on elimination diets, it is usually for a maximum of 3-4 months to reduce symptoms, calm inflammation and allow healing and addressing the overgrowth itself. And many FODMAP-containing foods are extremely healthy and part of having rich microbiome diversity and building short chain fatty acids which prevent inflammation in the gut and promote a robust immune systems. Remaining on a highly restrictive diet for months or years may reduce microbial diversity and make the gut ecosystem less resilient over time. Having chronically low levels of beneficial ``good` bacteria is just as harmful as having overgrowths of the opportunist ´´bad guys´´.

I have also found among my clients that long-term food avoidance can also increase anxiety around eating, making it tough to access the rest-and-digest part of the parasympathetic nervous system necessary to digest and absorb our food. Clients often have so much food fear that they unnecessarily cut out even more foods they aren``t even reactive to just to go about their days with less digestive stress. Long term restrictive diets also just plain don`t work.. as they fail to resolve the root cause of symptoms - WHY is your body reacting to so many foods to begin with.

Looking Beyond the Bacteria

One of the most important principles in functional medicine is recognising that bacterial overgrowth is usually a consequence of an underlying imbalance—not simply the problem itself.

Questions we ask include:

• Why did the bacteria overgrow in the first place?

• Is stomach acid adequate?

• Is digestive function impaired?

• Is intestinal motility reduced?

• Has there been chronic stress affecting gut function?

• Are there previous infections or other contributing factors?

• Are there lifestyle or dietary factors that need addressing?

Unless these underlying conditions are identified and corrected, bacterial overgrowth is much more likely to recur.

My Functional Medicine Approach

When working with clients with SIBO, I take a comprehensive approach that goes beyond simply eliminating foods. Treatment is tailored to each individual but generally includes:

• Ordering and interpreting SIBO breath testing where appropriate.

• Identifying and addressing the underlying terrain or conditions that allowed the bacterial overgrowth to develop.

• Supporting healthy digestion and normal gut function.

• Using carefully selected, evidence-informed botanical antimicrobials where appropriate to target bacterial overgrowth.

• Supporting the gut throughout treatment.

• Gradually and systematically reintroducing foods to rebuild dietary diversity and support a healthier microbiome.

Rather than encouraging long-term restriction, the aim is to restore resilience so that as many foods as possible can comfortably return to your diet. Digestive symptoms rarely exist in isolation. The health of the gut is closely connected with stress, sleep, immune function, hormones, nutrition, and the nervous system.By looking beyond symptom management and working to understand why SIBO developed in the first place, you can improve your long term digestive health - and all the other systems impacted by it!

If you’ve been told to simply avoid more and more foods but still don’t feel well, it may be time to look deeper. Understanding the root causes of SIBO—and addressing both the bacterial overgrowth and the factors that allowed it to develop—offers a more comprehensive and long-term approach to healing. I would love to be a part of your gut healing journey. Reach out to learn more about working with me,