Low-FODMAP Diet Explained: A Practical Guide for IBS Relief
If one of our clinicians recommended a low-FODMAP diet for ongoing gastrointestinal symptoms, you are not alone. Low-FODMAP can help many people identify food triggers and calm symptoms like bloating, gas, abdominal pain, and irregular bowel habits. Below, you will learn what low-FODMAP means, when and how it is used, and what to discuss with your healthcare provider before you start.
What is the low-FODMAP diet?
FODMAPs are fermentable short-chain carbohydrates that are poorly absorbed in some people. When they reach the large intestine, gut bacteria ferment them, producing gas and drawing water into the bowel. This can lead to bloating, distension, cramping, pain, diarrhea, or constipation in individuals with sensitive guts, especially those with Irritable Bowel Syndrome (IBS). Monash University researchers developed the low-FODMAP approach, and it is now widely used in clinical practice.
FODMAP categories include:
Oligosaccharides: fructans and GOS in wheat, rye, onions, garlic, legumes
Disaccharides: lactose in milk and some yogurts
Monosaccharides: excess free fructose in certain fruits, honey, high-fructose corn syrup
Polyols: sorbitol, mannitol, xylitol in some fruits and sugar-free products.
When is low-FODMAP recommended?
Major gastroenterology guidelines support a time-limited trial of the low-FODMAP diet to improve global IBS symptoms. It is commonly used for patients with IBS and may be helpful in select cases of functional GI symptoms. Discuss with your clinician whether testing for other conditions should occur before dietary restriction.
How does it work? The three phases
Monash describes a three-step process. Work with a clinician or dietitian whenever possible.
Elimination
Short period, typically 2 to 6 weeks, choosing lower-FODMAP alternatives to calm symptoms.Reintroduction
Systematically test one FODMAP group at a time to identify personal triggers and tolerances.Personalization
Build a long-term, diverse diet that limits only your problem foods while keeping overall nutrition strong.
Evidence: how effective is it?
Randomized and controlled studies show meaningful benefit for many patients with IBS:
In a US trial, 40 to 50 percent reported adequate relief, with greater improvements in pain and bloating versus a comparison diet.
Reviews report that about 70 percent of people with IBS feel better on a low-FODMAP plan when guided properly.
Guidelines recommend trying the diet short term with professional support, then liberalizing during personalization.
Common high- vs low-FODMAP examples
(Portions matter. Use a reputable food list or app and individualize with your clinician.)
Often high-FODMAP: apples, pears, mango, honey, wheat-based breads and pastas, garlic, onion, legumes, milk and soft cheeses, sugar alcohols in sugar-free gum or candies.
Often low-FODMAP: oranges, strawberries, blueberries, kiwi, rice and oats, potatoes, carrots, zucchini, spinach, lactose-free milk or hard cheeses, eggs, firm tofu, garlic-infused oil.
How to follow low-FODMAP safely
Confirm diagnosis and rule out other conditions if indicated. Your clinician may discuss celiac testing, inflammatory markers, or stool tests based on symptoms.
Work with a dietitian for meal planning, portion sizes, and reintroduction timing. The Monash FODMAP app is a practical tool for food lookups and serving guidance.
Track symptoms during each phase. Keep notes on food, portion, timing, and GI response.
Prioritize nutrition: protein, fiber from tolerated sources, calcium, and micronutrients.
Who should be cautious or seek supervision?
Low-FODMAP is not ideal for everyone. Use extra caution and professional guidance if you:
Have a history of disordered eating or unintentional weight loss
Are pregnant, breastfeeding, elderly, or underweight
Are managing complex medical conditions that require specialized diets
Plan to keep the elimination phase longer than recommended
Guidelines favor short-term elimination with a timely reintroduction to protect diet quality and the microbiome.
Quick tips for getting started
Swap wheat for rice, oats, quinoa, or certified low-FODMAP breads
Use garlic-infused oil instead of whole garlic or onion for flavor
Choose lactose-free dairy or hard cheeses
Build plates with lean protein, low-FODMAP vegetables, and tolerated fruit
Reintroduce foods one group at a time to pinpoint triggers
When to contact a clinician
Reach out if you have persistent abdominal pain, unexplained weight loss, rectal bleeding, fever, night symptoms, or symptoms that do not improve with a time-limited low-FODMAP trial. Your clinician can help refine the plan and consider other diagnoses.
References
Nanayakkara, W. S., Skidmore, P. M., O'Brien, L., Wilkinson, T. J., & Gearry, R. B. (2016). Efficacy of the low FODMAP diet for treating irritable bowel syndrome: the evidence to date. Clinical and experimental gastroenterology, 9, 131–142. https://doi.org/10.2147/CEG.S86798
Eswaran, S. L., Chey, W. D., Han-Markey, T., Ball, S., & Jackson, K. (2016). A Randomized Controlled Trial Comparing the Low FODMAP Diet vs. Modified NICE Guidelines in US Adults with IBS-D. The American journal of gastroenterology, 111(12), 1824–1832. https://doi.org/10.1038/ajg.2016.434
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