FODMAPs: could they be causing your bloating, diarrhea, constipation and other IBS-like digestive issues?

IBS (irritable bowel syndrome) is the most common GI (gastrointestinal) disorder and affects the quality of life of 1 in 5 Americans. (1) Many of you may feel too familiar already with the most common IBS symptoms: bloating, abdominal pain, discomfort or cramping, gas, constipation and diarrhea. Even if you don’t have IBS, you might still experience some of these symptoms, which are signs that your digestion isn’t at its best.

The severity of these symptoms can range from being simply annoying to significantly disrupting your life. Going Paleo or basing your diet on REAL food by avoiding processed foods can help many IBS sufferers tame their unpleasant GI  symptoms by eliminating many gut–irritating compounds, such as the hard-to-digest proteins found in grains, soy and dairy and other processed ingredients like monosodium glutamate (MSG), artificial sweeteners and refined sugars to only name a few.

… but if your IBS hasn’t improved or has gotten worse despite making these dietary changes, FODMAPs could be to blame.

FODMAPs and Fructose Malabsorption

FODMAPs is an acronym coined by researchers based in Melbourne, Australia and stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols.

In other words, FODMAPs represent a group of short-chain fermentable carbohydrates which have the property of being easily fermented by the bacteria in your gut, depending on your gut health and gut flora. And this not a good thing!

This fermentation process produces a lot of gas, which can obviously make you gassy and bloated and can also induce changes in your bowel movements, in addition to attracting a lot of water into your intestines through osmosis, further contributing to the bloating and sometimes leading to osmotic, or watery, diarrhea.

Where are these FODMAPs?

FODMAPs currently include fructose, lactose, fructans, galactans, sorbitol and mannitol, but they haven’t all been identified yet and data regarding the FODMAP content of many foods isn’t available. Fructose malabsorption is the term used to refer to the inability to properly absorb fructose and is often associated with an intolerance to other FODMAPs too. If you malabsorb FODMAPs, they will be available to be fermented by the bacteria in your intestines. It’s just like having your own personal and internal micro-brewery…!

Fortunately, the Paleo diet naturally eliminates many FODMAPs, such as the lactose in dairy, fructans in wheat and rye, galactans in beans, sugar-alcohols in sugar-free processed foods and a significant amount of fructose found in foods and beverages sweetened with high-fructose corn syrup (HFCS).  However, many Paleo foods, especially plant foods such as some vegetables, fruits, tubers and nuts, contain other natural fermentable short-chain carbohydrates that could interfere with your digestive health.

Everybody reacts differently to FODMAPs. For example, you could be reacting to fructose and lactose, while someone else could be sensitive to fructans only and another one could have hit the jackpot and experience problems with all FODMAPs.  You may also be reacting to only some frutan-containing foods or could have symptoms only if you consume a certain amount of FODMAPs within a certain period of time.

Understanding what foods contain these sugary treats the bacteria in your gut may be loving a bit too much can help you start solving the mystery of your IBS symptoms so you can adjust your diet accordingly and say goodbye to your GI problems.


Although fructose is the main sugar found in fruits, it doesn’t mean that you have to completely avoid them to get relief from your IBS symptoms. Simply eliminating the fruits that contain more fructose than glucose and not eating large amounts of fruits at once can be sufficient for many people to prevent fructose malabsorption. Fruits with the highest fructose content include apples, cherries, grapes, mangos, pears, watermelon and ripe bananas.

Fructose is also found in a few vegetables. Put artichoke, asparagus, sugar snap peas and large servings of tomato (especially tomato sauce and tomato paste) on your watch list too. And, of course, try to stay away from all sweeteners, especially honey and agave syrup, for at least few weeks because of their high fructose content.


Fructans are another type of carbohydrate made of a bunch of fructose attached to one another that can easily be fermented by the bacteria in your gut. The most common food sources are onions (all types including leeks, shallots and onion powder), garlic, cabbage, Jerusalem artichoke, okra, radicchio, fennel, beetroot, Brussel sprouts and broccoli.

Most prebiotics, a term that literally means food for bacteria, naturally contain fructans, including inulin, chicory root and fructo-oligosaccharides (FOS). Watch for them in your probiotics or other health foods.


The other most common source of FODMAPs in the Paleo diet is polyols, which is just another term to refer to sugar alcohols. Even if you avoid food products sweetened with isomalt, xylitol, mannitol and sorbitol, some of these polyols are also naturally present in some food. For example, snow peas, apricots, blackberries, cherries, nectarines, peaches, plums and other stone fruits as well as watermelon, persimmon and pears contain high amounts of polyols.

Moderate quantities of polyols are also present in avocado, cauliflower, celery, mushrooms, lychee, sweet potatoes and yams. Take care reading the ingredient list of any supplements or medications you take and beware of any ingredients ending in –ol.

A Word of Caution For Coconut and Nuts

The FODMAP content of coconut products has not been measured yet. Coconut oil is unlikely to be problematic since it is free of carbohydrates and fiber, but desiccated coconut, coconut flour and coconut butter could contribute to your IBS symptoms. Even coconut milk or coconut cream may contain some types of fermentable carbohydrates either naturally or from the added gums (read the ingredient list to choose a gum-free brand).

The same goes for nuts and nut butters. The only nut with published FODMAP values so far is pistachios, which is apparently high in fructans. It is very likely that other nuts also contain FODMAPs. Even though we don’t know enough about the FODMAP content of nuts, they can be quite irritant for your digestive tract and giving your gut a break could really help you alleviate your symptoms.

What should you do if you suspect FODMAPs trigger your IBS?

Pulling all FODMAP-rich foods out of your diet for at least 2 weeks, ideally 4, in an elimination diet fashion is the first thing to do to determine whether the bacteria in your gut are over-fermenting these short-chain carbohydrates.

Don’t worry, there are still a few safe vegetable options for you for you to eat during the elimination phase of your low-FOMDAP diet, such as green beans, carrots, zucchini, cucumber, lettuce, spinach, kale and olives. Avoid raw vegetables and consider eating only small amounts of peeled and thoroughly cooked vegetables if you experience a lot of GI symptoms. Bell peppers and eggplant are also low in FODMAPs, but be careful because they belong to the nightshade family and can induce IBS symptoms in some people. If you miss the taste of onion, you can use the green parts of green onions, chives or asafoetida powder instead. Garlic-infused oil is another great way to add a garlicky flavor to your dish sans its fermentable fructans. Don’t skimp on sea salt, pepper, herbs, spices, ginger and vinegar to make sure your low-FODMAP diet is not bland.

You can also include fruits that contain more glucose than fructose. Glucose facilitates the absorption of fructose, which helps to prevent fructose from being fermented by your gut flora. Low-fructose fruits are usually well tolerated. Try bananas that are greenish or just ripe, blueberries, strawberries, grapes, cantaloupe, citrus fruits, pineapple, papaya and passion fruits. Limit yourself to no more than one serving at a time and no more than two servings a day for best results. If your IBS symptoms are significant, try having them cooked and peeled to facilitate their digestion or simply stay away from fruits for a few weeks to give your intestines time to rest and recover.

If your bloating, gas and bowel movements improve by eliminating high-FODMAP foods, you’ll know that you are up to something.  Once you manage to be symptom-free for at least 5 days in a row, you can try reintroducing FODMAPs, one at a time, every 3-4 days, to see which food you tolerate or not. Remember that the amount and the different types of FODMAPs you eat can have a cumulative effect. Keep a food journal to help you keep track or ask for help from a health professional familiar with FOMDAPs specialized in GI health.

If you don’t see any difference on a Paleo low-FODMAP diet, FODMAPs may not be part of what is causing your IBS. Maybe other food sensitivities or SIBO (small intestinal bacterial overgrowth) could be to blame. Don’t give up! 🙂

Low- and High-FODMAP Paleo Foods

Foods Low-FODMAPs High-FODMAPs
Vegetables Green beans, carrots, zucchini, cucumber, lettuce, spinach, kale, olives, bell peppers, eggplant, green part of green onions, chives, white potatoes Artichoke, asparagus, sugar snap peas, tomato sauce and paste, leeks, shallots, onions, garlic, cabbage, Jerusalem artichoke, okra, radicchio, fennel, beetroot, Brussels sprouts and broccoli, snow peas, avocado, mushroom, cauliflower, celery, sweet potatoes, yams
Fruits Bananas (greenish or just ripe), blueberries, strawberries, cantaloupe, citrus, fruits pineapple, papaya, passion fruits Apples, cherries, grapes, mangos, pears, watermelon, ripe bananas, apricots, blackberries, stone fruits (nectarines, peaches, plums), persimmon, lychee
Fats All None
Protein All None, unless prepared with high-FODMAP ingredients
Coconut Coconut oil Coconut butter, desiccated coconut, coconut milk, coconut flour
Nuts None Pistachios and most nuts and nut butters (data only available for pistachios, but other nuts are usually also bothersome for people sensitive to FODMAPs)
Sweeteners Maple syrup, dextrose, sucrose, brown rice syrup Sugar-alcohols (isomalt, mannitol, sorbitol), honey, agave syrup, HFCS (high-fructose corn syrup)
Other Sea salt, pepper, herbs, spices, ginger, vinegar… Sugar alcohols, inulin, chicory root, FOS (fructo-oligosaccharides), gums, prebiotic

Download your free FODMAP food list here.

Download the pdf version  of this Paleo low-FODMAP diet food list here.

Bottom Line

If you want your digestive health to be optimal, FODMAPs might be one of the many things (along with gluten, dairy, sugar and legumes) that might be problematic for you. Abnormal digestion is a sign that your health is not optimal. Health starts in the gut, so make sure you get your digestion in order if you want to achieve optimal health.

If you need extra help to get there:

* Article originally published in Paleo Magazine.

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(1)     National Digestive Diseases Information Clearinghouse. Irritable Bowel Syndrome. September 2007.

(2)     Eastern Health Clinical School, Monash University. The Low-FODMAP diet: reducing poorly absorbed sugars to control gastrointestinal symptoms. 2011. [can be ordered here]

(3)     Susan J. Shepherd and Peter R. Gibson. Fructose Malabsorption and Symptoms of Irritable Bowel Syndrome: Guidelines for Effective Dietary Management. Journal of the American Dietetic Association. 2006; 106: 1631-1639.

(4)     Peter R. Gibson and Susan J. Shepherd. Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach. Journal of Gastroenterology and Hepatology. 2010; 25: 252–258.