IBS & Low-FODMAP Diet: Complete Guide

Last updated: 20 February 2026

An IBS diet is an eating pattern that can help manage irritable bowel syndrome (IBS) symptoms such as bloating, pain, and bowel habit changes. It often includes regular meals, appropriate fibre, and for many people a low-FODMAP diet (sometimes called a FODMAPs diet) under the guidance of a dietitian. An IBS diet plan structures these choices into daily meals. This guide explains what an IBS diet and the low-FODMAP (FODMAPs) diet are, how they work, what to eat and avoid, benefits and risks, and a sample day. This page is for education only. IBS should be diagnosed by a doctor; the low-FODMAP diet is best done with a dietitian. Do not change your diet or medication based on this article alone.

Disclaimer: The information on this page is for education only and does not replace advice from your doctor or dietitian. IBS needs proper diagnosis. The low-FODMAP diet should be undertaken with a dietitian to avoid unnecessary restriction and to do reintroduction safely. Do not follow a strict long-term low-FODMAP diet without professional guidance.

Below: what the IBS diet and low-FODMAP (FODMAPs diet) are, how an IBS diet plan works, what to eat and avoid (with a table), benefits and risks, a sample day, and answers to common questions. You can use our calorie calculator and TDEE calculator with your dietitian if you have a weight or calorie goal.

What is the IBS diet?

An IBS diet is any eating approach used to help control IBS symptoms. There is no single “IBS diet”–guidelines typically suggest:

  • Regular meals: Eating at consistent times and not skipping meals.
  • Fibre: Adjusting fibre type and amount; soluble fibre (e.g. oats, some fruits and vegetables) may help some people; excess insoluble fibre or sudden increases can worsen symptoms in others.
  • Limiting triggers: For example large fatty meals, excess caffeine, alcohol, and for some people high-FODMAP foods.

The low-FODMAP diet (or FODMAPs diet) is the best-researched dietary therapy for IBS. FODMAPs are fermentable carbohydrates (oligosaccharides, disaccharides, monosaccharides, and polyols) found in many foods; in some people with IBS they can cause bloating, pain, and diarrhoea or constipation. A low-FODMAP diet temporarily restricts high-FODMAP foods, then reintroduces them to identify personal triggers. An IBS diet plan can combine general advice with a dietitian-led low-FODMAP approach. For other digestive conditions, see our gastritis, GERD & digestive diet and bland, soft & BRAT diet guides.

How the IBS diet and low-FODMAP diet work

General IBS diet advice works by reducing known irritants (large meals, excess fat, caffeine, alcohol) and balancing fibre. The low-FODMAP diet works by reducing fermentable carbohydrates that draw water into the gut and are fermented by bacteria, which can trigger symptoms in sensitive people. It is done in three phases:

  1. Restriction: For a limited period (often 2–6 weeks), high-FODMAP foods are replaced with low-FODMAP alternatives.
  2. Reintroduction: High-FODMAP foods are reintroduced in small amounts to see which ones (and how much) you tolerate.
  3. Personalisation: You keep only the restrictions that are needed for you, so the diet is as varied as possible long term.

An IBS diet plan from a dietitian will tailor this to you. Do not stay on strict low-FODMAP indefinitely–it can affect fibre and nutrient intake. Use our calorie calculator and TDEE calculator only as a general reference if you need to manage weight; do not restrict calories heavily while on low-FODMAP without advice.

What to eat and what to limit (IBS and low-FODMAP)

The table below gives a general picture. For strict low-FODMAP, portion sizes and detailed lists matter–a dietitian will provide an IBS diet plan and FODMAP lists. This is for education only.

Eat (general IBS / low-FODMAP examples) Limit or avoid (high-FODMAP examples)
Oats, rice, quinoa, gluten-free bread (in low-FODMAP portions); many vegetables (e.g. carrot, cucumber, spinach, courgette); bananas, blueberries, strawberries (in allowed portions); lactose-free dairy or small amounts of hard cheese; lean meat, fish, eggs; maple syrup (small amounts)Onions, garlic; wheat and rye in large amounts; legumes (e.g. chickpeas, lentils) in large portions; honey; high-fructose fruits (e.g. apples, mangoes, watermelon) in large amounts; sweeteners such as sorbitol, xylitol; excess fruit juice
Regular meals; soluble fibre as tolerated; plenty of fluidsLarge fatty meals; excess caffeine; excess alcohol; rapid increase in fibre

FODMAP content depends on portion and preparation. A FODMAPs diet or low-FODMAP diet should be followed with a dietitian and with a proper reintroduction phase. For a gentle diet during flares, see our bland, soft & BRAT diet (use only if your doctor or dietitian recommends it for your case).

Potential benefits (with caveats)

Benefits are described in general terms–individual results vary. This is not medical advice.

  • Symptom relief: Many people with IBS see improvement in bloating, pain, and bowel habit when following an IBS diet plan that includes low-FODMAP under dietitian guidance. Evidence supports low-FODMAP for IBS symptom reduction in the short term.
  • Identifying triggers: The reintroduction phase of the FODMAPs diet helps identify which FODMAPs (and amounts) you tolerate, so you can personalise your diet and avoid unnecessary long-term restriction.
  • Regular eating: General IBS diet advice (regular meals, smaller fatty meals) can help some people feel more in control of symptoms.

Evidence: guidelines recommend dietary modification including low-FODMAP for IBS, ideally with a dietitian. Diet does not replace medical care for IBS.

Risks and who should be cautious

An IBS diet that is balanced and, if used, low-FODMAP with professional support is generally safe. Points to watch:

  • Strict low-FODMAP long term: Staying on full restriction for months without reintroduction can reduce fibre and variety and affect gut bacteria. The low-FODMAP diet is meant to be a short restriction phase followed by reintroduction and personalisation. Do this with a dietitian.
  • Self-diagnosis: Do not assume you have IBS–get a diagnosis from a doctor. Other conditions (e.g. coeliac disease, inflammatory bowel disease) need different management.
  • Other conditions: If you have an eating disorder, malnutrition, or other health issues, a dietitian can ensure your IBS diet plan or FODMAPs diet is safe and adequate.

Before starting the low-FODMAP diet, speak to your doctor or dietitian.

Sample IBS diet plan day (low-FODMAP style)

This is one example of a day using low-FODMAP-style choices–not a prescriptive IBS diet plan. Portions and full lists should come from a dietitian.

  • Breakfast: Oats (allowed portion) with lactose-free milk or water, banana (ripe banana is lower FODMAP in small portion), and a few walnuts. Or eggs with gluten-free toast and spinach.
  • Lunch: Salad with cucumber, carrot, spinach, grilled chicken, olive oil, and a small portion of quinoa or gluten-free bread. Lactose-free yogurt and blueberries (allowed portion).
  • Dinner: Grilled fish or chicken with rice, steamed courgette and green beans, and a simple dressing. Fruit such as strawberries or orange in allowed portion.
  • Snacks: Rice cakes with peanut butter (check portion); carrot sticks; a small portion of low-FODMAP fruit; lactose-free milk or water.

Avoid onions and garlic in this example; use garlic-infused oil (FODMAPs are not fat-soluble) if your dietitian says it is suitable for you. For more ideas on balanced eating, see our Mediterranean diet and anti-inflammatory diet–adapt them to your personal FODMAP tolerance with a dietitian. If you need to lose weight, use our calorie deficit calculator and TDEE calculator with your doctor’s or dietitian’s approval.

Frequently asked questions

An IBS diet is an eating pattern that can help manage irritable bowel syndrome (IBS) symptoms. It often includes regular meals, appropriate fibre (soluble fibre may help), and may involve a low-FODMAP diet (FODMAPs diet) under dietitian guidance. An IBS diet plan structures this into daily choices. It does not replace medical care.

The low-FODMAP diet (or FODMAPs diet) limits foods high in FODMAPs–fermentable carbohydrates that can trigger bloating, pain, and bowel changes in some people with IBS. It has three phases: restriction, reintroduction, and personalisation. It should be done with a dietitian and is not meant to be followed strictly long term.

On a general IBS diet you can eat regular meals with soluble fibre (e.g. oats), and avoid large fatty meals and excess caffeine or alcohol. On the low-FODMAP phase you eat low-FODMAP foods (e.g. many vegetables and fruits in allowed portions, gluten-free grains, lactose-free dairy). See the article table and get an IBS diet plan from a dietitian.

It depends on your symptoms. Often advised: large fatty meals, excess caffeine, alcohol, and for some people excess insoluble fibre or gas-producing foods. On the low-FODMAP diet you temporarily avoid high-FODMAP foods (e.g. onions, garlic, wheat, some legumes, some fruits and sweeteners). A dietitian can tailor this to you.

An IBS diet plan can help you eat regularly and choose foods that suit your gut. For low-FODMAP, a dietitian-led plan is recommended so you get the right restriction phase and safe reintroduction. Do not stay on strict low-FODMAP long term without professional guidance.

Yes, for general reference. Our calorie calculator and TDEE calculator can help you maintain or adjust weight. If you are on low-FODMAP, focus on variety and adequacy–do not restrict calories severely. For weight loss with IBS, talk to your doctor or dietitian first.

Summary

An IBS diet helps manage irritable bowel syndrome through regular meals, appropriate fibre, and for many people a low-FODMAP diet (FODMAPs diet) under dietitian guidance. An IBS diet plan structures these choices. The low-FODMAP diet has three phases–restriction, reintroduction, and personalisation–and should not be followed strictly long term without professional support. This page is for education only; get a diagnosis from your doctor and an IBS diet plan or FODMAPs diet plan from a dietitian. See our gastritis, GERD & digestive diet, bland, soft & BRAT diet, and Mediterranean diet for related reading. Use our calorie calculator and TDEE calculator only with your healthcare team’s guidance if you are managing weight.

Use our calculators with this diet

Set your calorie target and plan meals with our free tools.

Other diet guides that may fit your goals.

Sources and further reading

This article is based on current guidance. For more detail, see:

  • NICE and other national guidelines on IBS management and diet
  • Monash University FODMAP research and resources (often cited in low-FODMAP guidance)
  • Dietetic association position papers on IBS and low-FODMAP diet

Last updated: 20 February 2026. Content is for educational purposes only and does not replace medical or dietetic advice. Do the low-FODMAP diet with a dietitian.

Content quality

Written by DietaBest Editorial Team

Medically reviewed by Dr. Alex Novak, MD (Internal Medicine)

Last updated:

This guide is for general education only and does not replace personal medical advice. Always talk to your doctor or a registered dietitian before making major diet or lifestyle changes, especially if you have a medical condition or take medication.