If you’ve ever struggled with bloating, digestive discomfort, or Irritable Bowel Syndrome (IBS), you may have come across the term “FODMAPs.” These short-chain carbohydrates and sugar alcohols are found in a variety of foods, from fruits and vegetables to dairy and grains.
While they are completely natural, for some people, particularly those with IBS or Small Intestinal Bacterial Overgrowth (SIBO), they can trigger uncomfortable digestive symptoms.
Understanding FODMAPs, how they interact with your gut, and whether they might be contributing to your symptoms is key to improving digestive health.
In this article, we’ll break down what FODMAPs are, their role in gut health, and how a low FODMAP diet can be used as a tool to manage symptoms while addressing underlying causes.
These short-chain carbohydrates and sugar alcohols are found in foods naturally (many fruits and some vegetables) or as food additives (found in cereals, honey, agave, lollies, cakes, biscuits, dairy products).
What are FODMAPs?
FODMAPs are found in the foods we eat. FODMAP is an acronym for:
- Fermentable
- Oligosaccharides (e.g. Fructans and Galacto-oligosaccharides (GOS))
- Disaccharides (eg. Lactose)
- Monosaccharides (e.g. excess Fructose)
- And
- Polyols (e.g. Sorbitol, Mannitol, Maltitol, Xylitol and Isomalt)
Some food sources are higher in the above constituents, and for many people, particularly those who experience IBS, they can be a trigger of symptoms. They may also impact people with SIBO and may be a potential consideration as a trigger for those with autoimmune diseases like rheumatoid arthritis, multiple sclerosis or eczema.
As the FODMAP molecules move slowly through the gastrointestinal tract, they’re poorly absorbed in the small intestine and attract water. As they continue along the digestive tract to the large intestine, they act as a food source to the bacteria that live there normally. The bacteria then digest (ferment) these FODMAPs, and can cause symptoms like bloating and gas. The extra gas and water cause the intestinal wall to stretch and expand. Because people with IBS have highly sensitive digestive tracts, this stretching can cause additional pain and discomfort. This may also alter how quickly the bowels move.
IBS and FODMAPs
Symptoms of IBS include abdominal bloating and distension, excess wind (flatulence), abdominal pain, nausea, changes in bowel habits (diarrhoea, constipation, or a combination of both), and other gastrointestinal symptoms.
If you do experience IBS, be aware that these foods may not be the only trigger for you. Whilst they may be responsible for your digestive upsets, you may remove these foods and still experience symptoms. That’s because other foods or chemicals can also trigger IBS.
Whilst for many avoiding FODMAP foods may be beneficial from a symptom management perspective, it may only serve as a band-aid treatment, and can act as a temporary relief while the underlying ‘root cause’ is managed.
Working with a functional medicine practitioner to determine and then treat the underlying cause is a critical step in regaining optimal digestive health, and is something our practitioners help patients with often. Removing these foods from your diet should be part of a well-formulated health plan and act as an important, but temporary, part of your recovery and treatment.
Can IBS and FODMAP foods cause a leaky gut or SIBO?
It’s unclear whether changes to gut barrier and intestinal permeability can be caused by IBS, or the irritation that FODMAP foods may cause the lining of the gastrointestinal tract. Some studies have found increased permeability with IBS-D sufferers (dominant diarrhoea) in both the small and large intestines, however, other studies have found no significant differences.
Activation of the immune system in the mucosal lining of the GIT may compromise the barrier function and alter nerve signaling within the enteric nervous system (sometimes referred to as the ‘second brain’, hence the gut-brain axis).
A leaky gut can lead to further activation of the immune system and systemic inflammation, measured by levels of lipopolysaccharides (LPS) in stool testing.
Up to 70% of IBS sufferers are known to also develop a small intestinal bacterial overgrowth (SIBO). Protocols of treatment for SIBO include dietary modification similar to and founded on low FODMAP diets. Breath testing should always be performed to confirm the presence of SIBO.
What are the FODMAP foods?
- Fructose: A sugar found in most fruits and vegetables like apples, mangoes, pears and watermelon
- Lactose: A sugar found in dairy foods like milk, soft cheeses and yogurts
- Fructans: Very similar to fructose, found in many vegetables (such as onions garlic, asparagus, broccoli, cabbage), grains (wholemeal bread, rye bread, wheat pasta) and cereals
- Galactans: Found primarily in legumes, such as beans, lentils, chickpeas and soybeans
- Polyols: Sugar alcohols like xylitol, sorbitol, maltitol and mannitol. You find them mainly in artificial sweeteners and chewing gum
For a comprehensive list of the foods to avoid and to consume on the low FODMAP diet, click here. Monash University has also developed an app Monash University FODMAP diet which can be downloaded for free. In this app, you can search for a specific food and identify the levels of FODMAPS in that food, using a traffic light system. Some foods may be acceptable in small amounts but not larger serves.
5 common misconceptions about FODMAPs
There are many misconceptions about the low FODMAP diet, leading to confusion about its purpose and effectiveness. Here are five common myths debunked.
1. The low FODMAP diet is a lifelong commitment.
False. The low FODMAP diet is a short-term approach, typically lasting 2–6 weeks. It’s followed by a structured reintroduction phase to help identify personal trigger foods, rather than being a permanent dietary change.
2. The low FODMAP diet is for weight loss.
False. The FODMAP diet is designed to manage IBS symptoms, not to promote weight loss. It focuses on substituting high-FODMAP foods with suitable alternatives rather than restricting calories.
3. The low FODMAP diet cures IBS.
False. While the diet can significantly reduce symptoms, it does not cure IBS. Managing IBS involves multiple factors, including stress management, lifestyle changes, and other dietary considerations.
4. The low FODMAP diet is gluten-free.
Not necessarily. Gluten is a protein, whereas FODMAPs are specific types of carbohydrates. Some gluten-containing foods are high in FODMAPs, but others are not. Likewise, not all gluten-free products are low in FODMAPs.
5. The low FODMAP diet benefits gut health.
Partially true, but with limitations. While reducing FODMAP foods can relieve symptoms, long-term restriction can decrease microbiome diversity and reduce fibre intake. This is why the diet is meant to be temporary, with a focus on reintroducing as many well-tolerated foods as possible.
Is it the food or your gut function?
Understanding FODMAPs and digestive health
Foods containing FODMAPS are healthy, nutritional, fibrous foods. Generally, they are foods that would be recommended to include in your diet, to provide a good supply of fibre and food for your microbiome. Microbiome richness and diversity mostly occurs through food and a rainbow coloured diet can provide the bacteria in our gastrointestinal tract (GIT) with a multiple of nutrients (vitamins, minerals, amino acids) and active constituents (polyphenols, antioxidants, phytosterols, phenolic compounds, dietary fibre), to feed on and populate to levels that support our whole body’s health.
In 2005, researchers at Monash University in Melbourne identified FODMAPs and developed the low FODMAP diet as a tool for managing irritable bowel syndrome (IBS).
However, digestive function plays a crucial role in how the body processes FODMAPs.
As food travels through the digestive tract there are many actions and functions that must take place. If any of these mechanisms are compromised the consequences may be felt as symptoms of reactivity to this group of foods.
By working with a functional medicine practitioner to assess and improve your gut function, you may be able to better tolerate FODMAP-containing foods over time.
What does a FODMAP diet protocol look like?
Avoiding FODMAP foods, while supporting GIT function for a period of time (e.g. 3 months) can improve symptoms of bloating, gas and diarrhoea or constipation. Eliminating these foods from the diet over this time allows the gastrointestinal tract to reduce bacteria that may be overgrown, reduce inflammation, calm the immune system and allow for beneficial bacteria to proliferate.
Once your gut is healed, you can likely reintroduce FODMAPs into your diet, but it’s important to do so gradually and systematically. Here are key points to consider:
- The low FODMAP diet is typically a temporary intervention, not a long-term diet
- After the initial elimination phase (usually 2-6 weeks), you should begin reintroducing high FODMAP foods one at a time
- Reintroduction helps identify which specific FODMAPs trigger your symptoms and which ones you can tolerate
- The reintroduction phase can take about eight weeks, during which you test each FODMAP category individually
- Once you’ve identified your triggers, you can create a personalised, sustainable diet plan that includes FODMAPs you tolerate well
- In the long term, it’s beneficial to include as many foods as possible in your diet to support a diverse gut microbiome
- Even if your gut has healed, you may still have some FODMAP sensitivities, so it’s important to pay attention to your body’s responses as you reintroduce foods
At MFM, we’re here to help you navigate this journey with expert guidance, offering tailored testing, dietary strategies, and practical support so you can restore your gut health and feel yourself again.
