Is It the Gluten or the FODMAPs? – A Confusion, Explained

A common misconception about the low FODMAP diet is that it is a gluten-free diet. This is understandable as gluten-containing grains - wheat, barley, and rye - are greatly reduced or avoided during the elimination phase. For some people, these foods trigger common digestive symptoms (gas, bloating, abdominal pain, constipation or diarrhea). What is it in these foods that is responsible for the symptoms? Let’s dig in.

Gluten vs Fructans

Gluten is the main protein in wheat, barley and rye and needs to be avoided by people diagnosed with celiac disease. People with non-celiac gluten sensitivity (NCGS), a newly recognized condition that occurs when someone has a reaction from eating gluten but does not have celiac disease or a wheat allergy, also feel better when avoiding these grains and their products. These conditions are typically diagnosed by a gastroenterologist. Finally, people with a wheat allergy need to avoid all varieties of wheat (including spelt, kamut, einkorn, farro/emmer and triticale).

Fructans are a type of carbohydrate in gluten-containing grains, one of the FODMAPs (within the larger category of oligosaccharides, the “O” in FODMAP – more on this topic in a future article of my FODMAP Series). The common confusion comes from the fact that both gluten and fructans co-exist in wheat, barley and rye. The reason why these grains are reduced in the low FODMAP diet is that the fructans are poorly digested in people with IBS and may trigger symptoms. During the elimination phase, gluten-free grains like rice, quinoa, buckwheat and millet become a staple but small amounts of wheat can still be included. The main wheat-containing food allowed is true sourdough bread, as the fructans have been “digested” by the live cultures during a long process of fermentation, which reduces the fructan content of the bread. Soy sauce and even one small slice of regular wheat bread are usually tolerated and considered low FODMAP. In conclusion, the low FODMAP diet is not a gluten-free diet.

Not all gluten-free products are low FODMAP

During the elimination phase of the low FODMAP diet people rely on gluten-free grains and some gluten-free alternatives to bread, pasta, crackers and cookies assuming these are low in FODMAPs. It is important to point out that not all these packaged products are necessarily low in FODMAPs. When looking at a gluten-free product you need to become an expert label reader. Although the main flours used are low FODMAP (rice, tapioca, cassava), there are very often high FODMAP ingredients such as honey, agave, pear or apple juice (used as sweeteners), inulin or chicory (added to increase the fiber content) and others.

Take home message

Many people report feeling better on a gluten-free diet but don’t necessarily know why. Is it because they are sensitive to gluten, or the fructans? If you are one of them, I strongly encourage you to get a proper diagnosis first. If celiac disease or NCGS are diagnosed, then you will know that you need to avoid gluten-containing grains and their products. If you are found to have a wheat allergy, you will need to avoid all wheat products.

If you don’t have any of these conditions or continue to have symptoms on a gluten-free diet, the fructans (FODMAPs) may be to blame. Working with a dietitian to identify the source of the problem may help you liberalize your diet and find that you don’t need to unnecessarily avoid all gluten-containing grains and products. Interestingly, a recent study from Monash University (Biesiekierski et al, Gastroenterology 2013) found that only a small percentage of the subjects who had both IBS and NCGS were indeed sensitive to gluten (8%) but all felt better while eating a low FODMAP diet, suggesting that the FODMAPs had the greatest impact in their digestive symptoms.

FODMAP Explained: “F” stands for Fermentable

Welcome to my FODMAP Explained series! This is a set of articles dedicated to explaining the acronym FODMAP and giving practical tips to avoid symptoms while including as wide a variety of foods as possible.


The first letter of the acronym FODMAP goes to the very core of the why some foods trigger the uncomfortable, painful symptoms of Irritable Bowel Syndrome (IBS): Fermentable. This refers to food particles that are poorly absorbed or cannot be absorbed at all in the small intestine, continue to travel down the gastrointestinal (GI) tract and reach the large intestine (or colon). There, our friendly gut bacteria feast on the them (they are their fast food!), and produce gases and other by-products (short-chain fatty acids, SCFA) as a result of their fermentation. This is a good thing but, in people with IBS, the gas production may lead to bloating, pain and changes in motility (diarrhea or constipation).

Why it’s important to include fermentable fibers

It’s a good idea to keep feeding our friendly gut bacteria as their presence has several health benefits:

  • They are like an army defending us from the harmful (disease-causing) bacteria – the higher the number, the less space there will be for the bad bacteria to find a place to reside.

  • The by-products of their fermentation confer health benefits: SCFA have been shown to help protect us from colon cancer.

  • They can produce vitamins (several B vitamins including vitamin B12, as well as vitamin K) and even amino acids.

  • They may have several more health benefits that currently being studied. For example, they may help us improve our immune system and fight obesity.

Not all fermentable fibers are FODMAPs.

What distinguishes FODMAPs from other fermentable fibers is the speed at which they are fermented. Those that are rapidly fermentable may lead to symptoms, whereas those that are slowly fermentable produce gas at a more steady rate, and are more gentle on the GI tract. What makes FODMAPs rapidly fermentable is their chemical structure: they are shorter chains of sugars than the slowly fermentable fibers, which are made of long chains of sugars.

Bottom line: what can you eat?

If you have IBS and are trying to alleviate your symptoms, here are some useful tips:

1.     Choose foods rich in slowly fermentable fibers to avoid diminishing the number of friendly bacteria in your gut (if we don’t feed them, they die). These include vegetables, fruits, whole grains, legumes and nuts. See examples in my article Prebiotics: How to Keep Your Friendly Bacteria Happy on a Low FODMAP Diet. Try my Easy Overnight Oats recipe (below) to start your day with some good-for-your-gut fiber.

2.     Be careful about having too many of these foods in the same meal or snack, as a high dose at one sitting may lead to symptoms. To start, keep it to two or three servings (check the Monash University FODMAP Diet App for appropriate portion sizes).

3.     Avoid or limit foods rich in rapidly fermentable fibers such as  garlic/onions or artichokes; wheat, rye and barley and their products (cereals, pasta, bread). Other foods that can be fermented by the bacteria as they are poorly absorbed are shorter sugars such as monosaccharides (the “M” in FODMAP) and disaccharides (the “D” in FODMAP) and sugar alcohols or polyols (the “P” in FODMAP) - more on these in the next issues of the FODMAP Explained series.

4.     As IBS is a very individualized condition, not everyone reacts the same way to fermentable foods. You may want to consult with a dietitian specialized in FODMAPs to find out which ones trigger your own symptoms.


Easy Overnight Oats


1 cup rolled oats

1 tablespoon plus 1 teaspoon chia seeds

2 cups unsweetened almond milk

1/2 teaspoon cinnamon (optional)

Topping, per serving:

½ cup fresh or frozen blueberries or raspberries, or fresh sliced strawberries


1.     Put the oats, chia seeds and cinnamon (if using) in a glass container or large jar with an airtight lid. Add the almond milk and stir to combine.

2.     Close with the lid and refrigerate overnight or up to 4 days.

3.     When ready to serve, portion out one serving into a bowl, and top with the fruit.

Variation: add 1 tablespoon unsweetened cocoa powder and a few drops of stevia to step one for “cocoa-flavored” morning oats. Top with either one of the fruit choices above (raspberries are especially good) or 2 tablespoons chopped almonds.

Chef’s tip: if you have mason jars, you can divide the oat mixture in 4 jars and top them with the fruit, then close the jar. Every morning you have one serving ready to grab and go. This works especially well if using frozen berries, as they will defrost overnight.


4 servings


Store in an airtight container in the refrigerator for up to 4 days.

3 Tips to Satisfy that Sweet Tooth on a Low FODMAP Diet

I am a firm believer that when it comes to diet, moderation is key, and no food is per se a “bad” food. We all need a treat once in a while, and for many people, that means a “sweet treat”. I have to admit, this time of year especially, with the holidays humming and the weather turning chilly, I find myself wanting to bake some special treat, or warm up with an occasional cup of hot chocolate. Perhaps because it reminds me of when, as a teenager, I was skiing in the Alps during the Christmas break, and, after hours in the freezing temperatures, my friends and I would warm our hands (and our tummies) around a cup of hot chocolate (see my recipe for Italian Hot Chocolate below).

Although there are many low FODMAP dessert choices out there, the issue for people with IBS is eating too much at one sitting. This may make you consume too much fructose at once and lead to unpleasant symptoms. Before I give you my tips to enjoy sweets without incurring into tummy trouble, it is useful to understand how fructose is absorbed.

Fructose is a single-sugar unit (a monosaccharide, the “M” in the acronym FODMAP) which can be absorbed in two different ways: the first is by diffusion, which means the fructose molecule crosses the intestinal wall on its own; the second is by “piggybacking” with glucose on a transporter molecule. The first method is a slow and inefficient process, which may leave unabsorbed molecules in the small intestine. The second method is the most efficient but works well only when there are equal amounts of glucose and fructose to be transported, as the two molecules are paired up in the transport system. If there is more fructose than glucose, the excess fructose is not taken up and remains in the small intestine. As it is a small molecule, fructose has a high osmotic capacity, which means it draws water, leading to diarrhea. When it then travels the large intestine, it is fermented by the gut bacteria, resulting in gas production and bloating.

Most of the fructose in our diet is found in fruit and in sweeteners (together with glucose). As both absorption methods may lead to unabsorbed fructose molecules lingering in the small intestine, how well fructose is absorbed depends both on the dose consumed and the fructose to glucose ratio. There are two keys to ensuring you don’t get symptoms from fructose: one is to choose fruits and sweeteners with a balance of glucose and fructose and avoid or limit those that contain more fructose than glucose; the second is to avoid eating too much sugar at one sitting, as too large of a fructose load will overwhelm the system.

3 Tips to Satisfy your Sweet Tooth on a Low FODMAP Diet


1. Choose fruits and sugars with a good balance of fructose and glucose:


Suitable fruits*:

  • Banana

  • Blueberries

  • Cantaloupe

  • Kiwifruit

  • Oranges/mandarins/clementines/tangelo

  • Grapefruit

  • Grapes

  • Papaya

  • Pineapple

  • Raspberries

  • Strawberries

Suitable Sweeteners*

  • Sucrose (aka table sugar, also known as beet/brown/cane/castor/confectioner’s/granulated/icing/organic/refined sugar; raw sugar crystals, can juice crystals, cane syrup, evaporated milled cane juice, simple/sugar syrup)

  • Glucose

  • Dextrose

  • Palm Sugar

  • 100% Maple Syrup

  • Corn Syrup (is it mostly glucose)

  • Rice malt syrup

  • Stevia, powdered or liquid (not a sugar, but a non-nutritive natural sweetener)

    *These are “suitable” in appropriate portions – See the Monash University Low FODMAP Diet App. Fruit: It is recommended to consume no more than one portion of fruit per meal or snack. You can have more than one portion of fruit in one day, just be sure to separate them by at least 2-3 hours.

2. Avoid fruits and sugar with excess fructose (unless you have re-challenged them and found you can tolerate them)

Unsuitable fruits

  • Apple

  • Boysenberries

  • Cherries

  • Figs

  • Mango

  • Pear

  • Watermelon

Note: there are other “high FODMAP” fruits not listed here as they are high in sorbitol (not fructose).

Unsuitable sweeteners

  • Agave

  • Coconut sugar

  • Golden syrup*

  • Honey

  • Molasses

  • Sorghum syrup*

Note: Most high-fructose corns syrup (HFCS) has a similar fructose/glucose ratio to sucrose (about 55% fructose and 45% glucose). However, the fructose amount may vary from 42 to 90%. As it is not possible to know from the label which kind of HFCS it is, it is best to avoid it.

*These are high in Fructans (not fructose), a type of oligosaccharides (the “O” in FODMAP). Fructans are chains of fructose molecules that travel to the large intestine undigested and are fermented by our gut bacteria.

Artificial Sweeteners (aspartame, sucralose, and saccharine) are low in FODMAPs but, as some preliminary studies are showing that they may be harmful to our gut bacteria, many dietitians (myself included) are starting to recommend avoiding them altogether.

3. Avoid large loads of fructose in one sitting

This is where it is easy to get confused by the plethora of “low FODMAP desserts” appearing every day on blogging sites. Sure, these desserts may be made with gluten-free flours, low-lactose dairy products, and other low FODMAP ingredients, but a dessert is only low FODMAP at a portion size that limits the fructose content (most likely from the sugar) to a certain threshold.

Beware of desserts that end up having high amounts of sugar per serving (such as some cakes, brownies, or desserts with frosting or cream fillings).  A good rule of thumb is to limit the amount of sugar to about 2-3 teaspoons (10-15 grams) per sitting. This is not unreasonable given that, FODMAPs aside, the American Heart Association recommends limiting the daily intake of added sugars to no more than 6 teaspoons (25 grams) for women and 9 teaspoons (36 grams) for men.

Going back to my initial “everything in moderation” message, if you follow a healthy diet without excess added sugars, come the holidays, you may enjoy a dessert without guilt. Still, if you want to avoid symptoms, make sure the piece is small, or, if you really want to indulge for once, keep your overall FODMAP level low during the rest of the day. Your tummy will thank you, and you will be able to really enjoy the time you spend with your friends a family!

hot chocolate in an espresso cup.jpg

Italian Hot Chocolate


1 teaspoon cornstarch

1/3 cup water

2/3 cup lactose-free milk (whole or 2%) or almond milk

1 ½ oz (42 g) 72% dark chocolate, finely chopped

2 teaspoons sugar


1.     In a small saucepan, dissolve the cornstarch in the water; add the milk and bring to a boil

2.     Lower the heat, and add the chocolate and sugar. Simmer for 1-2 minutes, stirring constantly, until the chocolate thickens.

3.     Pour into two 4-oz cups (preferably heated with hot water). Enjoy! 

2 servings (1 serving is equivalent to 10 grams of sugar, and under the low-FODMAP serving size for dark chocolate).

Note: this is so rich that you can make it into 4 servings and drink it, as it is popular now in Italian cafés, in espresso cups.

Got Beans? May Guide to Including Legumes on a Low FODMAP Diet

Legumes (also known as pulses) include beans, lentils and dried peas (chickpeas, split peas). Beyond the classic black, pinto, or garbanzo beans, you can now buy an incredible variety of lentils (red, yellow, green, black, split or not) and even heirloom beans, with different colors, flavors and shape.

If you thought legumes were boring, think again. Just a virtual visit to the cuisines or India (dals and channa masala), Morocco (Harira), the Mediterranean (Italian Ribollita), Latin America (black bean soup or pozole) and Japan (soy beans) will start making your head spinning with new ideas on how to vary your intake of legumes. And these are just a few examples. One could write and entire book on the different ways you could cook these nutritional powerhouses. Indeed, let’s then talk about why they are so good for us.

The Benefits of Legumes

First of all, they are the cheapest way (for your wallet and for the earth) to get protein in your diet. But if you think that they are “poor people’s” food, I am going to tell you that they are also “lucky people’s” food. Yes, because, in addition to the protein, they contain slow-digesting carbohydrates, tons of fiber, and come packaged with minerals (iron, magnesium, calcium, potassium), vitamins (folic acid and other B vitamins) and phytochemicals. Here is what they can do for us:

1)    Help with weight management and blood sugar regulation.Their high fiber content helps us feel full longer, and digest food slower. Even their carbohydrate portion is digested very slowly and helps improve blood glucose control and thus prevent (or control) diabetes.

2)     Help with constipation: they contain insoluble fiber, which creates bulk and moves stool through the GI tract faster.

3)     Help keep healthy cholesterol levels: they are one of the few foods high in soluble fiber, which binds cholesterol and helps excrete it (I wrote more on the subject in a previous article). They are also very low in saturated fat, and may help reduce the risk of cardiovascular disease when they replace high-saturated fat foods like burgers or cheese.

4)     Protect the body against disease as they contain antioxidants and other bioactive compounds. Although foods like blueberries and broccoli are more famous for their antioxidant content (you may have heard of anthocyanins and sulfuraphanes), legumes contain flavonoids, lignans, phytosterols, and other bioactive compounds that may protect us from chronic disease and inflammation.

5)     Help maintain a healthy gut due to their prebiotic fiber, which is the fast food for our good gut bacteria.

The American Diabetes Association, the American Heart Association and the American Cancer Society all recommend legumes as one of the most important food groups for disease prevention and optimal health.

Legumes on a low FODMAP diet

Legumes are rich in prebiotic fibers known as oligosaccharides (mostly GOS, or galacto-oligosaccharides, and also fructans). As humans don’t have the enzymes necessary to break these molecules down, they go through our GI tract unabsorbed, end up in the large intestine, where our gut bacteria digest them and use them for energy. Unfortunately, the result of this fermentation process is gas, and for people with IBS, it’s an exaggerated amount of gas, which can also induce bloating and pain.

For this reason, most beans, lentils, and dried peas are excluded during the elimination phase of the low FODMAP diet. Studies have shown that after only 3-4 weeks of a low FODMAP protocol, the gut bacteria diminish in variety and numbers due to a low prebiotic fiber intake. The good news is that they can repopulate after re-introducing foods high in prebiotics. Most people find that they tolerate some or most legumes, either in smaller or even larger portions.

Here is how to prepare them to minimize the gas production:

  • During the elimination diet, you can have small amounts (no more than ½ cup) of canned chickpeas and lentils as they as low enough in FODMAPs to be suitable for this phase.

  • Afterwards, if you pass the GOS challenge, you can start by reintroducing small amounts of other canned beans first, as the canning process drastically lowers the amounts of FODMAPs. You can read more about the effect of food processing on FODMAPs here. Be sure to drain them and rinse them well.

  • To increase the variety of beans in your diet, you may also want to try cooking them yourself. Soak them overnight, discard the soaking water, and cook them in fresh water until they are very soft. Start with channa dal, urad dal, and chickpeas (lowest in FODMAPs), then try butter beans, and red or green lentils. Last, try the higher-FODMAP varieties: soy, borlotti, lima, red kidney beans, and split peas (highest!).

  • Finally, the enzyme supplement alpha-galactosidase helps some people tolerate beans more easily.

Tips for cooking and eating legumes

  • Plan ahead: soak them the night before you intend to eat them. If you forget, stock your pantry with a few cans your favorite legumes to have some handy.

  • If you don’t have the time to cook them when you set out to make lunch or dinner, prepare them ahead of time (for example during the weekend), and store them in airtight containers or even freeze them in the portions you know you will need for your favorite recipes.

  • Add herbs and spices to vary the flavor: they are delicious! Cumin and coriander, when added to the cooking water, also help decrease the gas production.

  • You can add beans or chickpeas to any salad for a complete meal; prepare a quinoa-tabbouleh and add some chickpeas.

  • Have them as a snack: try my Spiced Roasted Chickpeas recipe.

  • Replace part of the ground beef in your Bolognese sauce with canned lentils.

  • Make your own hummus: You can use garlic-infused olive oil to replace the garlic, and canned chickpeas. Blend in a mixer with some lemon juice, a little water and salt to taste, then add cumin and paprika for additional flavor. Divide into the portion size that correspond to a maximum of ½ cup chickpeas.

  • Put them in soups or stews. Just start with the smallest amount you know you can tolerate, then slowly increase the portions and see how you tolerate them. Try my Mexican Lentil Chili below.

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Mexican Lentil Chili


1 cup quinoa, rinsed and drained

1 Tablespoon olive oil

½ cup chopped green tops of scallions (1 oz.)

1 medium red or orange bell pepper (1/3 lb.), small dice

1 small green chili, de-seeded and minced

1-2 teaspoons chili powder (depending on desired level of heat)*

1 teaspoon ground cumin

½ teaspoon salt

1, 14-oz can diced tomatoes

1, 15-oz can black or brown lentils, drained and rinsed

½ oz dark (60 or 70%) chocolate, finely chopped

½ teaspoon lemon juice (optional)

3 Tablespoons chopped cilantro

*Make sure to check the ingredients’ list as some chili powder blends add garlic and/or onion. Spicy foods may be a trigger for some people. Adjust amount of chili powder according to tolerance.


1.      Bring 1 and 1/2 cups water to a boil. Add a pinch of salt and quinoa. Bring back to a simmer, then lower the heat, cover and cook for 10-12 minutes. Stir, cover and let the quinoa rest for 5 minutes.

2.      While the quinoa is cooking, heat the oil in a Dutch oven or soup pot over medium heat. Add the scallion tops, bell pepper, and green chili. Cook for 6-7 minutes, until softened. Check and stir often, adding some water, if needed.

3.      Add chili powder, cumin and salt and stir for 1 minute.

4.      Add tomatoes and simmer, stirring occasionally, for 10-12 minutes, until thickened.

5.      Stir in lentils, quinoa, chocolate, and ½ cup water. Let simmer for an additional 5 minutes, until flavors have blended.

6.      Taste and add lemon juice, if desired, and adjust for salt, if needed.

7.      Garnish with cilantro. Serve with corn tortillas on the side.


4 servings


Store in the refrigerator for up to 4 days or in the freezer for up to 2 months.