Low Fodmap Diet FAQs

If you have started the low-FODMAP diet as a way to calm your gut from symptoms of Irritable Bowel Syndrome (IBS), chances are you have many, many questions. The questions you see below have been asked over the years from fans of FODMAPLife. You may very well find your answer below!

It’s important to meet your daily nutritional requirements and seek professional advice before you begin any type of elimination diet. FODMAPs occur naturally in many healthy and beneficial foods and are common additives in packaged foods and medications. Please seek the advice of a dietitian who has experience working with clients on the low-FODMAP diet.

Frequently Asked Questions (FAQs) about the low-FODMAP diet

“What is the low-FODMAP diet?”

The low-FODMAP diet is a scientifically proven method to help reduce symptoms of Irritable Bowel Syndrome (IBS).  The diet helps to uncover possible symptom triggers. It consists of the Elimination Phase where foods that are high in FODMAPs are to be avoided during the first phase, (see below, “What are FODMAPs”). Then during the Rechallenge Phase, 10 FODMAP containing foods are challenged in three portions, from smaller to larger. A person following the diet then records any possible problematic FODMAPs and quantities in a Food & Symptom Diary. The other things the person records in their diary is any daily stressful situations that might be triggering symptoms, as well as bowel movements. After a person understands their triggers, they move on to a Modified Low-FODMAP Diet, where they know which FODMAPs to completely avoid, and which whole serving sizes of FODMAPs, or smaller quantities of FODMAPs they can enjoy with ease. The low-FODMAP diet is like a personal experiment and FODMAP tolerance will differ from person to person.  So if one person says a certain FODMAP containing food does not exacerbate their symptoms, it does not mean that the next person will not have the same positive outcome. That’s why carefully following the diet is key. See My Top Posts for the Low-FODMAP Diet, Great for Newbies!

“What are FODMAPs? What does ‘FODMAP’ stand for?”

FODMAPs are a collection of short-chain carbohydrates (sugars and fibers) and sugar alcohols that are present in foods naturally or are present in man-made food additives. FODMAPs are poorly absorbed in the small intestine, are highly osmotic substances (meaning they pull water into the bowel) and are rapidly fermented by bacteria.  When we digest food and drinks our bodies physically and chemically break them down into simpler forms, to help us so to absorb the nutrients.  However, many of these carbohydrates can still remain poorly absorbed in the small intestine.

  • Fermentable – When the undigested carbohydrates reach the colon, the bacteria that normally live there rapidly ferment them, resulting in the production of gas. The build-up of gas in the colon can result in discomfort, bloating, abdominal distention and pain. Experts agree these symptoms are much more intense in for people like us with IBS, because we are already hyper-sensitive to even normal stimuli.
  • Oligosaccharides – Fructans and  Galactans –
    • Fructans are oligosaccharides made of fructose molecule chains that are completely malabsorbed because the small intestine lacks hydrolases to break their fructose-fructose bond.  Fructan-containing foods include high amounts of wheat and wheat products—such as bread and pasta.  Other fructan containing foods include onions, onion powder, shallots, garlic, garlic powder, leek bulbs, barley, cabbage (savoy), pistachios (Oligos GOS and fructans), artichokes, chicory root (inulin), and asparagus (Oligos GOS and fructans and excess fructose).  Wheat and onions contribute about 95% of fructans in the American diet.
    • Galactans (Galactooligosaccharides (GOS)) are oligosaccharides containing chains of the sugar galactose.  They are diverse short chains of galactose molecules “that can cause symptoms due to gas production and fermentation. The human body lacks the enzymes to hydrolyze them into digestible components, so they are completely malabsorbed.”  Different foods containing galactans include Jerusalem artichoke, different types of beans, chickpeas, lentils, peas and more.
  • Disaccharides – Lactose (also known as milk sugar).  The low-FODMAP diet negates high amounts of lactose which is found in milk, buttermilk, custard, cream, yogurt, kefir, soft unripened cheeses and ice cream.  You can still have foods that contain lactose, as long as the amount of lactose is present in small amounts (such as Parmesan, Swiss, and Havarti cheeses).  The diet includes certain lactose-free dairy and dairy-free products.
  • Monosaccharides – Fructose (also known as fruit sugar).  High amounts of fructose are to be avoided.  High-fructose containing foods (where fructose is in excess of glucose) include certain fruits (such as boysenberry, granny smith apples, pink lady apples, figs etc.), high-fructose corn syrup (HFCS), honey and agave syrup.  Based on clinical observations by Peter Gibson and Sue Shepherd, avoiding foods and beverages that contain greater than 0.5 g of fructose in excess of glucose per 100 g and/or greater than 3 g of fructose per serving regardless of glucose (considered a fructose load) is desirable to minimize symptoms.  {Gibson PR, Shepherd SJ. Evidence-based dietary management of functional gastrointestinal symptoms:  The FODMAP approach.  J Gastroenterol Hepatol. 2010;25(2):252-258.}
  • Polyols – Sugar alcohols are found in certain fruits and vegetables including apricots, avocados, blackberries, peaches and plums, mushrooms, and cauliflower. They are also used as artificial sweeteners such as sorbitol, mannitol, xylitol, maltitol, isomalt, lactitol, and erythritol. You may have seen labels on sugar-free products that use Polyols stating: “excessive consumption may cause a laxative effect”. Read labels carefully on sugar-free products like these so as to avoid sugar alcohols: gums, candies, chocolates, protein powders and bars, jams and preserves and cough drops.

“A study by Böhn et al. examining self-reported dietary intolerances in IBS found that 70% of surveyed patients reported sensitivity to foods high in FODMAPs, 49% reported sensitivity to dairy products (high in lactose), 36% were sensitive to beans (galactans) and 23% were sensitive to plums (fructose + polyols). {Dietary fructose intolerance, fructan intolerance and FODMAPs}.

“Who is the low-FODMAP diet for?”

Here are a couple of pointers to help you figure out if the low-FODMAP diet is for you.  The diet may help you if:

  • You experience digestive symptoms such as excess gas (wind), bloating, abdominal pain, abdominal distention, diarrhea (IBS-D), constipation (IBS-C) or alternating diarrhea and constipation (IBS-A)
  • You have been diagnosed by your physician as having IBS
  • You have been tested for celiac disease and it has been ruled out
  • You have time in your schedule to take on this diet and meal prep and cook!
  • You do not have any negative relationships with food such as an eating disorder or disordered eating
  • Your physician or dietitian has suggested the low-FODMAP diet based on your health history and symptoms
  • You have Inflammatory bowel disease (IBD) and are not experiencing a flare
  • If you have celiac disease, are on a gluten-free diet, but still experience excess gas (wind), abdominal pain, and distention, bloating, diarrhea or constipation then FODMAPs could be to blame.  Says Patsy Catsos, MS, RDN, LD:  “talk with your doctor to make sure your gluten antibody levels reflect a 100% gluten-free diet and ask an expert in gluten-free eating to review your diet for hidden sources of gluten. Then consider a trial FODMAP-elimination diet to see if your symptoms improve. Be especially watchful of FODMAP ingredients added to boost the fiber content of gluten-free bread and baked goods.”
  • You have Small Intestinal Bacterial Overgrowth (SIBO) with IBS-like symptoms – the low-FODMAP diet may help, however, no scientific research has proven it (just yet)
  • You have Gastroesophageal reflux disease (GERD).  If you have GERD, I posted a question on my Facebook page recently to get feedback from people with GERD, asking if and how the low-FODMAP diet has helped them so you hear from others:

FODMAPs aren’t bad. Many foods high-FODMAP foods encourage the growth of good bacteria in the gut!  It’s essential to follow all phases of the diet to uncover your triggers so you can add FODMAPs back into your diet. The diet is not supposed to be followed long-term.

“How long should one try a low-FODMAP diet before they can expect results?”

Depending on how well your digestive system adjusts to no longer having any high-FODMAP foods, the Elimination Phase can take anywhere from 2-6 weeks.

“Where Can I Find a Low-FODMAP Foods List?”

You can Low Fodmap list click here or download the FODMAP Friendly app for $2.99 or the Monash FODMAP App for $12.99.

“How do I know when to subtract or reintroduce a FODMAP food?”

When you are following the low-FODMAP diet, in the first phase, called the Elimination Phase, you are essentially “subtracting” foods because you are avoiding foods high in FODMAPs. If while you are in the Elimination Phase and mostly eating foods that have been tested and analyzed to be low-FODMAP, but you feel a low-FODMAP food is triggering symptoms, then please avoid that food and make note in your Food & Symptom Diary of what and how much you ate and the symptoms you feel might have come from the food.

The low-FODMAP list of foods you see published by Monash University and the FODMAP Friendly Food Program is simply a guide to follow, and the list isn’t bullet-proof. So just because a food is indeed labeled as low-FODMAP, it doesn’t mean that someone won’t have a reaction to it. Each one of us has a different gut and different set of health and lifestyle circumstances that can affect how our digestive systems handle food. As an example: cucumbers are low-FODMAP at a ½ cup serving. I personally can only handle about 1-2 slices of cucumber, otherwise, I find myself burping or gassy.

You will know it is time to reintroduce a food after you have completed the Rechallenge Phase. That is when you will have a better understanding of your FODMAP threshold – meaning how much of one or a few FODMAPs you can handle over the course of a day, a couple days or per week.

“How Can I Add the Flavor of Garlic or Onion to My Meals?”

Onion, onion powder, garlic and garlic powder are all high in the FODMAP fructans. The good news, however, is that you don’t have to go without the taste of onion or garlic.

“Is there a preference for eating cooked or raw vegetables?”

For the low-FODMAP diet, no there is not a preference or set protocol on how you are supposed to eat your vegetables, however, people with sensitive guts tend to have a bit harder time digesting vegetables. Here are some precautions you can take when it comes to raw or cooked vegetables:

If you are having raw vegetables, try not to have too many varieties at once. Remember to thoroughly chew vegetables and all other foods.

Low-FODMAP cruciferous vegetables such as broccoli, cabbage, collard greens, kale, turnips, bok choy and leafy greens may be easier on your gut if cooked and not raw. The different ways you can cook vegetables are to bake, simmer, sauté, or lightly steam them.

“Would you recommend enzyme therapy when on a low-FODMAP diet?”

During the diet, I would not recommend a person to try enzymes. If anything, they are best to be added back after the elimination phase. After the diet, you can talk with your nutritionist or physician about trying Assist Full Spectrum Enzymes. They are free of FODMAPs, dairy free, soy free, non-GMO and vegan, and do not appear to have any high-FODMAP ingredients.

Also, consider delaying supplements or new medications until after you’ve completed the diet. If you are expecting to be treated for small intestinal bacterial overgrowth (SIBO) with antibiotics, you should finish antibiotic treatment immediately before beginning a low-FODMAP diet. Please again speak with your physician about your plans for the diet and about your supplemental and medicinal regimen.

“Are fiber supplements recommended on a low-FODMAP diet?”

From my experience, no they are not suggested for two reasons –

1) Just like enzymes, supplements and new medications should be delayed as should fiber supplements. You are essentially conducting an experiment on yourself so it’s best to not let something throw off your diet, as you want as accurate reading of your possible triggers.

2) We’ve been told for most of our lives that we NEED MORE FIBER! Fiber is essential to good health but when it comes to people with IBS, sometimes too much (or too little) fiber can be disastrous. It’s better to get fiber from foods and slowly increase the amount of fiber you consume from low FODMAP foods. Choose from a wide variety of low-FODMAP fruits and vegetables, grains and legumes, nuts and seeds. Be mindful of serving sizes for all low-FODMAP foods.

“How can I best follow a low-FODMAP diet when dining out/away from home?”

  • If you are traveling, keep a few low-FODMAP snacks on hand – see examples of 45 Low-FODMAP Snack Ideas and product ideas on my Low-FODMAP Brands page.
  • Look up menus online ahead of time to find something you can choose.
  • If going to a restaurant, call the restaurant ahead of time and explain the foods you need to avoid. Start by letting them know you need to avoid onions, garlic, wheat and dairy, as that should help eliminate most of the heavy-hitting FODMAP recipes from the menu. See if they can make something special for you or try and agree on a protein with low-FODMAP vegetables and something like rice or quinoa. *The low-FODMAP diet is a lactose-free diet, not a dairy-free diet, but eliminating dairy should make everything easier – plus I’ve rarely seen restaurants advertise lactose-free recipes.
  • Download my guide for Low-FODMAP Dining Out Tips.
  • Choose cuisines where you may have the option to have a protein paired with vegetables, without any FODMAPs like garlic, onion, or sauces, marinades or condiments, which almost always have hidden FODMAPs. Stir fry, salads, meat/fish with veggies or potatoes, omelets and burgers in lettuce wraps are usually easy to customize to order low-FODMAP at Asian restaurants, Steakhouses, diners, vegetarian cafes or burger joints.
  • If you can find a restaurant that has gluten-free options, you may have more choices. Just again check all ingredients in foods for FODMAPs.
  • Avoid sauces, or anything cream-based.
  • Avoid salad dressings as most have FODMAPs. If possible ask for olive oil with lemon and herbs as your dressing. 1 tablespoon balsamic vinegar or 2 tablespoons rice wine vinegar are OK to add to your salad dressing.
  • If ordering meat, ask if it’s been pre-seasoned or marinated with FODMAPs such as garlic, onions, honey a lot of ketchup or BBQ sauce, and if so, say you’d like your meat to order and can only accept it made with salt and pepper or herbs.
  • There are more great tips for eating out at Low-FODMAP Diet books

“I have been following a low-FODMAP diet for a year and some foods are still not tolerated well. Is this normal?”

I am assuming some of the foods you are speaking are low-FODMAP foods. Yes, it can be normal for foods that are low-FODMAP to still trigger symptoms. Have you been using the correct serving sizes? How have you prepared the foods? Are any of these foods packaged and if so, did you know all of the ingredients?

If you feel it’s nothing stress related that’s setting off symptoms and that every time these specific foods are triggering symptoms then you’ll need to keep track of those foods and the amounts you are consuming as well as how these foods are prepared when you’re eating them. That way you can discover that maybe you don’t need to avoid the food completely, just at a smaller serving, consumed less frequently or that it’s best to avoid altogether. IBS is so individualized so what works for you may not work for the next person with IBS.

Also, if you’ve been having trouble and have been on the diet for a year (which is much too long) please seriously consider working with a FODMAP-trained dietitian.

I’d like to note that the low-FODMAP diet is not meant to be followed long-term. It’s essential you work with your nutritionist to safely rechallenge FODMAPs back into your diet, as we all need a wide a variety of foods in our diets. If some foods are still not tolerated as well they may be the foods you will want to avoid for a while and you can then see further down the line if you can challenge them back into your diet again to see if they still cause issues.

Of course, as long as there’s no digestive upset, most FODMAPs are actually good for us (not including something like HFCS). Most FODMAPs are not bad, as they are actually prebiotics, which is food for our gut bacteria. Prebiotics nourish the good bacteria that everyone already has in their gut and fertilizes these good bacteria as they stifle the production of the bad, disease-causing bacteria.

Some examples of some low-FODMAP foods that are prebiotics are canned lentils (drained and rinsed to release FODMAPs), ripe bananas, inulin, Jerusalem artichoke and common cabbage.

“What is High Fructose Corn Syrup and Where is it Found?”

HFCS is high in FODMAPs. This sweetener is made from corn starch that has been processed by glucose isomerase to convert some of its glucose into fructose. Some examples of where you will find HFCS in foods are:

Soda, juice, ketchup, applesauce, jams and jellies, preserves, BBQ sauce, steak sauce, maple syrup, dressings, marinades, spice packets, relish, soup, bread, cereal, cookies, crackers, processed and flavored oatmeal, bread crumbs, cold cuts, KRAFT Miracle Whip, pickles, yogurt, creamer, chocolate sauce, and more!

“Is Corn Syrup Low-FODMAP?”


“Why can I have canned chickpeas, canned lentils and canned artichokes on the low-FODMAP diet?”

The reason why you can have canned chickpeas, canned lentils and canned artichokes on the low-FODMAP diet is that as they sit in a can, the FODMAPs within these legumes leach out into the brine-water mixture.  So you can enjoy them as long as you drain the contents of the can and then wash away any remaining FODMAPs off of the chickpeas, lentils or artichokes.

  • Low-FODMAP serving canned chickpeas: 1/4 cup.  Avoid sprouted chickpeas as they are HIGH in FODMAPs.
  • Low-FODMAP serving canned lentils: 1/2 cup.  You can also have green or red boiled lentils at a 1/4 cup serving.
  • Low-FODMAP serving canned artichokes: 1/8 cup artichoke hearts.
    • For artichokes, the combination of acid (from the vinegar) and the ‘leaching’ greatly lower the FODMAP (fructan) content of the artichokes.

“Do I have to watch how much fruit I consume, even if it is low-FODMAP?”

Yes. The rule of thumb for the low-FODMAP diet is to avoid large servings of any fruit and have one serving of low-FODMAP fruit per sitting/meal. One serving could be 20 blueberries or two half low-FODMAP servings such as 10 blueberries and 1 small kiwi.  Limit fruit juice and dried fruit to safe low-FODMAP servings as specified by the FODMAP Friendly app and Monash FODMAP apps, or review my grocery list here

Like smoothies? It’s best to make your own at home unless you can make yours customized at a smoothie bar. Learn how to make a low-FODMAP smoothie here.

“What type of Sourdough Bread can I have?”

According to Monash University researchers, traditionally-fermented sourdough bread (made from lower FODMAP flours such as spelt and oat) are classed as low or moderate in FODMAP content. “We know that the levels of FODMAPs (specifically fructans) are reduced during the sourdough fermentation process. It appears that fructans are used by the yeasts and lactobacilli during fermentation. However, sourdough bread made from high FODMAP flours (such as wheat and rye) still tends to be high in FODMAPs. The best approach is to ask your baker, which flours are used, how the bread is prepared and if traditional sourdough techniques have been used (ie. an overnight proving).”

“What kind of meat, seafood, and shellfish can I have?”

You can enjoy most any type of meat, seafood or shellfish as long as it has not been marinated in high-FODMAPs such as onion, garlic, high-FODMAP BBQ sauce, high-FODMAP ketchup, etc. Also, some sausages are made with high-FODMAPS, such as wheat, apples and dried fruits. Meatballs can also be made with breadcrumbs, dried fruits, fresh fruits, onions, and garlic.  When ordering out, it’s best to just stick to meats that have not been marinated and avoid processed meats. Also, some processed deli meats are made with carrageenan which may irritate the gut.

“I love cheese!  Can you tell me which kinds I can enjoy?”

I love cheese too!  Good news, there are many kinds of cheese you can enjoy on the low-FODMAP diet.  Stick to hard cheeses (think Parmesan which has trace amounts of lactose) and other matured or ‘ripened’ cheeses (such as brie, camembert, and feta cheese). Cream cheese, ricotta cheese, and haloumi cheese contain moderate amounts of lactose and should be avoided during the Elimination Phase. If you know that you do not malabsorb lactose then you do not have to restrict any cheese or other high-lactose foods. For a full list of low-FODMAP cheese please review my grocery list here.

“I live in the United States.  What are some certified Low-FODMAP products that I can try?”

Please check out my list of low-FODMAP brands here.  Many can be purchased on Amazon.com!

“I live in Australia.  What are some certified Low-FODMAP products that I can try?”

Check out this list of certified Low-FODMAP products from the FODMAP Friendly Food program.  Some of my favorites are FODMAPPED, Kez’s Kitchen, The FODMAP Friendly Tea Co., Wilde Beer and Simply Wize!

Medications, OTC Drugs and FODMAPs

Believe it or not, some medications contain high-FODMAPs. If you have found that any of your medications contain the following FODMAPs, discuss it with your physician to see if it’s possible to try a different medication. Some FODMAPs you may find in medicine include: Oligosaccharides -(inulin, chicory root,chicory root fiber – categorized as oligofructose or fructooligosaccharides (FOS)), Monosaccharides (sweeteners such as fructose, HFCS, honey, agave), Disaccharides (lactose found in milk products, milk powder, whey {without a lactose-free claim}, milk solids) and Polyols (sugar alcohols such as sorbitol, mannitol, xylitol, maltitol).  Kate Scarlata RD, RDN has a great post about how medications could also cause GI distress – read more here.

The difference between Fructose Malabsorption and Hereditary Fructose Intolerance

First of all, what is fructose?  Fructose is also known as fruit sugar. It’s a monosaccharide, a single sugar molecule.  After you eat a food containing fructose, some of the fructose is absorbed by special cells in your small intestine.  If you’re a healthy person without fructose malabsorption, you can probably absorb around 50 grams of fructose per meal or sitting. For those with fructose malabsorption, the cells in your small intestine cannot handle fructose properly and absorption is much lower, around 25 grams or even less, such as 5 grams.  Then the bacteria in your large intestine have a feast on the unabsorbed fructose, producing gases and triggering symptoms such as bloating, flatulence, diarrhea and abdominal pain and cramps.  The severity of symptoms and the amount of fructose that can be handled varies from one person to the next.  Fructose malabsorption may be diagnosed using the hydrogen breath test, however, recent research has shown that the hydrogen breath test may not be as reliable as perceived.  That’s why following a low-FODMAP diet may be a better avenue to take in order to determine how much fructose you can consume before experiencing symptoms. Reducing the number of fructans (essentially long chains of fructose molecules) may also improve symptoms.

“To better compare results from hydrogen breath tests and to understand the true prevalence of fructose malabsorption, revision and standardization of testing protocols are needed. Ideally, individuals should be tested not only with pure fructose but also, and perhaps more preferably, with fructose in food forms that better reflect real-life consumption.”  Fructose Malabsorption and Intolerance: Effects of Fructose with and without Simultaneous Glucose Ingestion.  Marie E. Latulippe and Suzanne M. Skoog.

Fructose Malabsorption (may also be referred to as dietary fructose intolerance (DFI)) comes with uncomfortable, annoying, lifestyle changing symptoms, while Hereditary Fructose Intolerance (HFI) can be serious if left undiagnosed. Both can cause malabsorption illnesses and both can be treated with changes in diet.

Fructose malabsorption is more common and affects 1 in 3 people.  Some people do not realize they have it and then show symptoms later in life. Fructose malabsoprtion is defined as the incomplete absorption of fructose in the small intestine, followed by the delivery of fructose to the distal small bowel and colon, where it contributes to rapid fermentation and abdominal bloating as a result of the fermentation.

Where can you find fructose? Take a look at this list from the Food Intolerance Network of the FRUCTOSE CONTENT OF FOODS. Fructose is found in fruits, vegetables, thousands of processed foods, like soda, sugary drinks, sauces, marinades, salad dressings, energy bars, cereals, and pickles. Foods naturally rich in fructose include agave, honey, molasses, dried fruits, fruits, and fruit juices.  While following the low-FODMAP diet, the goal is to reduce high-fructose foods to see if fructose is the issue (or one of the issues) for a person experiencing symptoms of IBS.  You can then see if you need to avoid all fructose or just certain foods or amounts of foods containing fructose.  Larger amounts of fructose may also be tolerated when glucose is added.  Use a journal and monitor the foods and drinks you consume to help find a threshold level that is easy to live with.

Nearly 75% of those who have fructose malabsorption also suffer from lactose intolerance

Hereditary Fructose Intolerance (HFI) happens when the enzyme for breaking down Fructose is not produced.  It is rare as it affects less than one in 10,000 people. HFI is inherited (genetic) so it stays with you for life.  A stool test (DNA test) from your doctor is the way to receive a positive diagnosis.  A fructose-free diet is followed for life and HFI cannot be cured.

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