IBS diet: Is low FODMAP the answer for you?


by Alessandra Stasnopolis, RDN, LDN

Aug 25, 2022

IBS, or irritable bowel syndrome, plagues 5-10% of the global population, making it the most common gastrointestinal disorder in the world. IBS is characterized by bloating, gas, abdominal pain, irregular bowel movements, upper GI upset and many other symptoms.

If you’re living with IBS, you may have heard about the low FODMAP diet protocol. Or maybe you haven’t—well, you’re in the right place! Here’s what to know if you’re considering the low FODMAP diet to help you manage IBS.

What is the low-FODMAP diet?

IBS is complex and research continues to grow on ways to manage and treat it. One of these researched treatments is the low FODMAP diet, which was pioneered by Monash University in Australia.

For people with IBS, certain foods can be harder to digest or process. FODMAPs—or fermentable, oligosaccharides, disaccharides, monosaccharides and polyols—are carbohydrates that are not 100% digested or absorbed in the human body.

These specific carbs move slower through our gastrointestinal tract, making them pull water in, stretch the walls of the intestines and create extra gas from fermentation. Since people with IBS have a more sensitive system and experience more pain and discomfort than those without IBS, these types of carbohydrates may be harder to tolerate.

The low FODMAP diet is designed to avoid these carbohydrates and then slowly reintroduce them to see what each person can tolerate. This diet is only recommended for those who have been diagnosed with IBS.

How the low FODMAP diet works

I want to start by pointing out that this is not a permanent elimination diet. There is a re-introductory phase included in order to figure out which categories you struggle with the most. If you are interested in trying this protocol, you should seek out guidance from a registered dietitian who is experienced in helping people with IBS.

Step 1: Elimination phase

This process takes 2-6 weeks to complete, depending on your symptoms. You start by cutting out all the foods listed below. It is important to discuss with a dietitian what foods you can eat that have fiber and work toward a balanced diet despite these restrictions. An unplanned elimination phase can lead to low fiber intake and nutritional deficiencies.

Food TypeHigh FODMAP Foods
VeggiesArtichoke, asparagus, beets (fresh), brussels sprouts, cauliflower, garlic, green peas, leek bulb, mushrooms (button, portobello, shitake), onion, savoy cabbage, scallion (bulb or white part), shallot, snow peas, sugar snap peas and sundried tomatoes
FruitsApples, apple juice, apricot, banana (ripe), blackberries, boysenberries, cherries, currants, dates, most dried fruit, grapefruit, mango, nectarines, peaches, pears, plums, prunes, tamarillo and watermelon
Dairy and non-dairy alternativesCheese (soft) ricotta, cottage or cream, condensed milk, cow’s, goat’s and sheep’s milk, custard, evaporated milk, ice cream, soy milk (made with whole soybeans), sweetened condensed milk and yogurt
Breads and cerealsWheat, rye, and barley-based products
Nuts and seedsCashews and pistachios
ProteinAnimal proteins (chicken, fish, beef etc) marinated with garlic and/or onion (except garlic/onion oil), baked beans, black beans, boriotti beans, broad beans, fava beans, kidney beans, lima beans, navy beans, pinto beans, silken tofu, soybeans (mature), soy flour, soy milk (made with whole soybeans) and split peas
Baking products and additivesAgave syrup, chicory root extract, flour blends (with wheat or bean), garlic salt or powder, high fructose corn syrup, honey, inulin or FOS, mannitol, molassess, onion salt or powder, sorbitol, most sugar free gums, mints and candies and xylitol
BeveragesDrinks made with cow’s milk, most fruit juices, rum, oolong tea, chamomile tea, fennel tea, strong chai tea and kombucha.

Step 2: Re-introductory phase

This process may take a month or more to complete. During this time, you’ll work with a dietitian to introduce foods from each category (FODMAP) one at a time. It’s important to work with a trained expert in this step because there are specific test foods, measurements and test timing for each category. This is extremely hard to do without help or knowledge of this process but with the right help, it can be simple and insightful in your IBS management.

Step 3: Management

Once you complete the whole process, you’ll have a better idea of what categories of food give you the most symptoms. You’ll mainly avoid those foods; however, it’s always encouraged to test them out from time to time to see if over time you can tolerate small amounts.

Nothing about this diet is permanent and all foods may eventually be able to fit in moderation. You are unique, and it’s all about finding what works best for your body!

Does the low FODMAP diet work for IBS?

The low FODMAP diet elimination process has been shown to be 50-86% effective in clinical studies. However, the maintenance phase has not been tested thoroughly. Research has shown that the low FODMAP diet can reduce pain, discomfort, distension, bloating and improve bowel movements (reduce constipation and diarrhea), as well as improve quality of life (2). That said, 1 in 4 people will not see improvements on the low FODMAP diet and may need other therapies in conjunction to find relief.

So, is low FODMAP right for you?

IBS is a very complicated condition, and everyone is different. It is important to weigh your options before trying the low FODMAP diet. This protocol can be time-consuming, limiting and expensive. It’s also important to note that working with a dietitian who has experience in GI disorders may be able to help you without doing the low FODMAP diet protocol.

If you have a prior history of eating disorders, you should talk with a mental health specialist and a doctor before trying it. Those with other preexisting conditions should also discuss the pros and cons of this diet before trying it.

Bottom line: you shouldn’t have to live with GI discomfort. Whether it’s the low FODMAP diet or other lifestyle changes, a registered dietitian can help pinpoint what works for you. If you’re under the care of a physician for IBS, you can also ask your doctor about dietary strategies.

Get care for IBS today or find a dietitian near you.

About the Author

Alessandra Stasnopolis, RDN, LDN, is a clinical dietitian and wellness coordinator in the Baylor Scott & White Health wellness department.

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