This is general health information only and is not a substitute for advice from your GP or healthcare professional.
1. What is the low-FODMAP diet?
The low-FODMAP diet is a dietary approach used primarily to manage symptoms of irritable bowel syndrome (IBS) and some other disorders of gut–brain interaction. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. These are short-chain carbohydrates that are poorly absorbed in the small intestine and can draw water into the bowel and be fermented by gut bacteria, contributing to bloating, abdominal pain, gas, and altered bowel habits.
2. Which foods are high in FODMAPs?
Common high-FODMAP foods include onions, garlic, wheat-based products, many legumes, some fruits such as apples, pears and mangoes, and dairy products containing significant amounts of lactose. Certain sweeteners, including honey and high-fructose corn syrup, and polyols such as sorbitol and mannitol can also be high in FODMAPs. The FODMAP content of a food can depend on the portion size.
3. What foods can I eat on a low-FODMAP diet?
Many foods remain available, including rice, oats, quinoa, potatoes, eggs, meat, fish, firm tofu, lactose-free dairy products, and many fruits and vegetables in appropriate portions. Examples of generally low-FODMAP fruits include strawberries, blueberries, grapes, oranges, kiwifruit and pineapple. The diet should focus on maintaining nutritional variety rather than simply removing large numbers of foods.
4. How does the low-FODMAP diet improve IBS symptoms?
Reducing FODMAP intake can decrease the amount of poorly absorbed carbohydrate reaching the lower intestine. This may reduce fermentation, gas production, intestinal water content, and distension. In people with visceral hypersensitivity, reducing these intestinal stimuli may also reduce abdominal pain and discomfort.
5. What are the three stages of the low-FODMAP diet?
The traditional approach consists of restriction, reintroduction, and personalisation. During the first stage, high-FODMAP foods are temporarily reduced. Individual FODMAP groups are then systematically reintroduced to identify which types and amounts trigger symptoms. The final stage involves developing a personalised diet containing as wide a variety of foods as possible while maintaining good symptom control.
6. How long should the strict low-FODMAP phase last?
The strict restriction phase is generally intended to be short term, usually around 2–6 weeks, rather than a permanent diet. If there has been no meaningful improvement after an appropriate trial, continuing strict restriction is unlikely to be beneficial and other causes or treatment strategies should be considered.
7. Is it safe to follow a low-FODMAP diet long term?
A strict low-FODMAP diet is not intended to be followed indefinitely. Prolonged unnecessary restriction can reduce dietary variety and may adversely affect fibre intake and the gut microbiome. The goal is therefore to reintroduce tolerated foods and establish the least restrictive diet that controls symptoms.
8. Should I see a dietitian before starting the low-FODMAP diet?
Ideally, yes. A dietitian experienced in gastrointestinal disorders can help ensure adequate fibre, calcium, protein and other nutrients while guiding systematic food reintroduction. This is particularly important for children, older adults, people with restrictive eating patterns, or anyone at risk of nutritional deficiency.
9. Is the low-FODMAP diet suitable for everyone with bloating or SIBO?
No. It is best established as a dietary treatment for IBS and some other disorders of gut–brain interaction. Although reducing FODMAPs may reduce symptoms in people with SIBO or other gastrointestinal conditions, it does not directly eliminate the underlying cause. It should not be used as a substitute for appropriate investigation and treatment of an underlying disorder.
10. What happens after completing the low-FODMAP diet?
The goal is not to remain on a highly restrictive diet. After symptoms improve, foods are systematically reintroduced, usually one FODMAP group at a time, to determine individual tolerance. Many people can eventually tolerate substantially more FODMAP-containing foods than during the initial restriction phase. The long-term aim is a personalised, nutritionally adequate and as varied a diet as possible, rather than avoiding FODMAPs completely.