Irritable bowel syndrome (IBS) is a common digestive disorder that results in diarrhea, constipation, or both, as well as bloating, gas and abdominal pain. It’s estimated that 5-10% of the world’s population – or roughly half a billion people - has IBS.
IBS is a complex disorder resulting in a wide spectrum of symptom severity across patients. IBS does not reduce lifespan but does contribute to substantial healthcare costs and reduced quality of life. While research is ongoing to determine best treatment strategies, a dietary protocol called the Low FODMAP Diet, is at the forefront of IBS symptom management.
What Is The Low FODMAP Diet?
FODMAPs are types of carbohydrates – oligo-, di-, and mono-saccharides and polyols - that are fermented by gut bacteria in the colon. In sensitive individuals such as those with IBS, this fermentation process leads to gas, bloating, constipation, diarrhea and abdominal pain.
The low FODMAP diet is an approach that restricts FODMAPs below a certain threshold in order to ease symptoms and reduce the amount of colonic fermentation. Knowing more about the acronym FODMAP can help guide food choices.
F – Fermentable – gas-producing
O – Oligosaccharides – a short chain of linked simple sugars (fructans, galactans)
D – Disaccharides – two linked simple sugars (lactose)
M – Monosaccharides – one simple sugar (fructose)
P – Polyols – sugar alcohols (xylitol, sorbitol, mannitol, isomalt)
What Foods Contain FODMAPs?
There are several categories of foods to limit on a low FODMAP diet based on their fermentable carbohydrate content.
|FODMAP||Type of Carbohydrate||High FODMAP Foods|
|Oligosaccharide (oligos, or GOS)||Galactans|
|Polyols||Sugar Alcohols – xylitol, sorbitol, mannitol, isomalt||Some fruits:|
What Are Some Low FODMAP Foods I Can Eat?
Portion sizes of foods often influence whether or not a food is a low, medium or high-FODMAP food. The list below includes foods that are considered low FODMAP for common serving sizes and portions.
Fruits – blueberries (1/4 cup), kiwifruit, lemon, limes, oranges/clementines, papaya, pineapple, plantains, rhubarb, starfruit, strawberries (5 whole)
Vegetables – arugula, lettuce, bamboo shoots, bean sprouts, pickled beetroot (2/3 cup), bell pepper, broccoli (heads only), cabbage, carrot, cassava, canned corn, green beans, collard greens, Swiss chard, kale, cucumber, eggplant, leek leaves, olives, potato, radish, spinach, pumpkin (1/3 cup), sweet potato (½ cup)
Grains – oats, quinoa, buckwheat, amaranth, rice, sourdough bread, some gluten-free bread
Dairy & Dairy-Alternatives – butter, hard cheese, lactose-free milk, almond milk (some may also tolerate yogurt well), unsweetened coconut milk beverage (¾ cup)
Aromatics – ginger, green onion/scallion/chives,
Sweeteners – Maple syrup, coconut sugar, turbinado, table sugar (sucrose), stevia
Legumes – garbanzo beans (¼ cup canned), lentils (¼ cup canned), lima beans
Fats/Nuts/Seeds – olive oil, avocado oil, coconut oil, flaxseed oil, macadamia nuts, flaxseed, chia seed, pumpkin seeds, sesame seeds, sunflower seeds
Proteins – seafood, poultry, eggs, red meat, Greek yogurt, firm tofu (1 cup cubed), tempeh
Beverages – water, sparkling water, tea, coffee, liquor, beer, most wine
An elimination diet is considered the gold standard for identifying food triggers associated with food sensitivities, intolerances and digestive symptoms. A low FODMAP diet is one such elimination diet and includes a 2 to 6-week elimination period, followed by a slow and intentional reintroduction phase lasting about 8-12 weeks. Reintroduction requires one FODMAP at a time, and one food at a time. Complete all your research first so you can properly plan out your diet and have enough low FODMAP foods and meals available when you’re hungry.
Make sure to track symptoms throughout the whole process to help you discover patterns. Working with a dietitian that specializes in IBS is ideal before you start this approach as the reintroduction phase is complex and often requires guidance to systematically reintroduce FODMAP groups and foods.
The Monash University FODMAP app is an excellent tool to use for the low FODMAP diet.
Can I Follow The Low FODMAP Diet Long-Term?
FODMAPs are fermentable by your gut bacteria and thus help beneficial bacteria thrive. Long-term avoidance of FODMAPs may interfere with a healthy balance of microbiota which may negatively influence your future digestive health.
Work to incorporate FODMAP groups back into your diet as directed by your dietitian. If you are unsuccessful or are unable to tolerate specific FODMAP groups or foods, you can try again in the near future. The goal is to minimize symptoms but also to liberalize your diet as much as possible to avoid nutrient deficiencies and unhealthy microbiota changes.
When To See The Doctor
If you are concerned about chronic symptoms you are experiencing that are not responsive to the low FODMAP diet, or symptoms worsen, schedule a visit with your doctor to discuss an appropriate plan of care.
While IBS may lead to uncomfortable and debilitating symptoms, restricting certain fermentable carbohydrates for a few weeks can ease symptoms and restore quality of life. A low FODMAP diet may feel restrictive but with adequate research and planning, a satisfying and nutritionally-dense can still be enjoyed. Reintroduction of FODMAPs is imperative for long-term gut health.
Irritable bowel syndrome (IBS) is a disorder that results in altered bowel habits such as constipation, diarrhea, or both, as well as gas, bloating, cramping and pain. Eliminating some foods has been shown to be an effective treatment for those with IBS.
FODMAPs are fermentable carbohydrates that contribute to digestive symptoms in susceptible individuals.
High FODMAP foods to avoid or limit for IBS include apples, pears, garlic, onion, wheat, beans, asparagus, mushrooms and more.
There are many healthy, low FODMAP foods you can enjoy such as oranges, kiwifruit, lettuce, carrot, potato, cucumber, quinoa, seeds, hard cheeses, butter, oils, eggs, seafood and meat. Some low FODMAP foods can become high FODMAP with a large-enough portion.
Limit high FODMAP foods for 2-6 weeks, then follow a slow and systematic reintroduction phase. Work with a dietitian to help guide you in this complex phase.
Since FODMAPs help to feed healthy bacteria, experts caution against following the low FODMAP diet long-term due to negative changes to microbiota in the colon.
Monash University. Starting the FODMAP Diet. Monashfodmap.com
IFFGD. The Low FODMAP Diet Approach. Aboutibs.org
American College of Gastroenterology. Low-FODMAP Diet. Gi.org
Monash University. Get the App. Monashfodmap.com