What you eat has a direct impact on how your digestive system functions. Food is one of the most common triggers of digestive symptoms – but the same way certain foods can cause discomfort, adjusting your diet can also dramatically improve those symptoms for people who are sensitive to them.
What is FODMAP?
FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols – a group of carbohydrates that are poorly absorbed in the small intestine. In sensitive individuals, they can trigger symptoms such as bloating, gas, abdominal pain and diarrhoea.
The four FODMAP groups are:
- Oligosaccharides: fructans and galacto-oligosaccharides, found in wheat, rye, onions and garlic
- Disaccharides: lactose, found in milk, yoghurt and soft cheese
- Monosaccharides: excess fructose, found in some fruits, honey and high-fructose corn syrup
- Polyols: sugar alcohols such as sorbitol, mannitol, xylitol and maltitol, found in some fruits, vegetables and sugar-free products
What is a Low-FODMAP Diet?
A low-FODMAP diet is a dietary approach that reduces intake of these carbohydrates to relieve symptoms in people with Irritable Bowel Syndrome (IBS) and other functional gastrointestinal disorders. It typically involves three stages:
1. Restriction – high-FODMAP foods are strictly removed from the diet, usually for 6 to 8 weeks, allowing time to notice a genuine difference in symptoms.
2. Reintroduction – high-FODMAP foods are gradually reintroduced one at a time, allowing you to identify exactly which foods trigger symptoms and which are well tolerated. If you're unsure whether a reaction is FODMAP-related or a separate food intolerance, a food intolerance test can help clarify what's going on alongside this process.
3. Personalisation – the diet is modified long-term, keeping only the foods that genuinely trigger symptoms restricted, while reintroducing everything else that's well tolerated. This stage is what makes the diet sustainable rather than restrictive indefinitely.
A low-FODMAP diet is intended to be temporary and should be followed under the guidance of a registered dietitian or healthcare provider, as it can lead to nutrient deficiencies if not managed correctly.
What Foods Can You Eat on a Low-FODMAP Diet?
- Fruits: berries, citrus fruits (oranges, lemons), kiwi, pineapple and ripe bananas are typically well tolerated
- Vegetables: leafy greens, bell peppers, carrots, aubergine, squash and sweet potatoes are usually fine
- Meat, fish and poultry: fresh, unprocessed options are allowed
- Dairy alternatives: lactose-free milk, soy, almond and rice milk are usually well tolerated. If dairy itself is the trigger rather than FODMAPs generally, it's worth reading about the difference between a milk allergy and milk intolerance
- Gluten-free grains: rice, quinoa and corn are allowed
- Nuts and seeds: almonds, macadamia nuts and sunflower seeds are usually well tolerated
When a Low-FODMAP Diet Isn't Recommended
A low-FODMAP diet isn't suitable for everyone, and should be avoided or approached with particular caution in these situations:
- Pregnant women: the diet may not provide enough nutrients for a growing baby
- Children: nutritional needs differ from adults, and the diet may not support growth and development adequately
- Those with a history of eating disorders: the restrictive nature of the diet could risk triggering disordered eating patterns
- Anyone with an undiagnosed digestive condition: coeliac disease and inflammatory bowel disease should be ruled out before starting, as a low-FODMAP diet may not be appropriate for these conditions
The diet should always be followed with guidance from a registered dietitian or healthcare provider, both to avoid nutrient deficiencies and to make sure it's the right approach for your specific symptoms.
What Are the Benefits of a Low-FODMAP Diet?
For people with IBS, a low-FODMAP diet can help reduce:
- Abdominal pain and discomfort
- Bloating
- Gas
- Constipation or diarrhoea
By limiting high-FODMAP foods, the diet reduces the amount of gas and fluid produced in the gut, which can ease bloating and pain, and may also help regulate gut motility. Since the diet isn't meant to be permanent, working with a dietitian to reintroduce FODMAPs gradually helps you build a sustainable, long-term eating pattern rather than an indefinitely restrictive one.
Can a Low-FODMAP Diet Help Mental Health?
There's some evidence that a low-FODMAP diet may support mental wellbeing in people with IBS, largely because IBS symptoms themselves can significantly affect quality of life and contribute to anxiety, low mood and social withdrawal. Reducing physical symptoms like bloating and pain can have a knock-on positive effect on overall wellbeing.
Identifying personal trigger foods can also help people feel more in control of their condition, which itself can support mental wellbeing. That said, a low-FODMAP diet should never be used as a standalone treatment for a mental health concern – anyone with mental health symptoms should speak to a qualified professional for proper diagnosis and support.
Planning Ahead
Keeping a credible high-FODMAP foods list to hand makes this diet far more manageable. Clearing high-FODMAP items from your fridge and cupboards during the restriction phase helps you prepare both practically and mentally for the change. Preparing shopping lists in advance, checking restaurant menus before you go out, and batch-prepping meals all make it easier to stay consistent – and consistency is what makes the reintroduction phase genuinely useful for identifying your real triggers.
