Low-FODMAP Diet – Foods to Avoid in IBS and Bloating

Short-Chain Carbohydrates May Cause Chronic Bloating and Diarrhea

It was found out that certain people complaining about abdominal bloating, excessive gas, chronic diarrhea or constipation, diagnosed with ‘dyspepsia’, irritable bowel syndrome (IBS) or functional bowel disease (FBD), actually cannot tolerate certain short-chained carbohydratescalled FODMAPs (1).

What Are FODMAPs?

FODMAPs (Fermentable Oligo-, Di-, and Mono-saccharides, And Polyols) are short-chain carbohydrates that are:

  • Osmotically active, so they, after ingesting, drag water from the intestinal vessels into the intestinal lumen, thus causing diarrhea
  • Fermentable (degradable by intestinal bacteria yielding large amount of gases, like hydrogen or carbon dioxide, thus causing abdominal bloating

FODMAPs include:

  • Oligosaccharides:
    • Fructans – chains of fructose with one glucose molecule on the end. Only minimal amounts of fructans may be absorbed in human intestine. They may interfere with absorption of fructose, thus aggravating symptoms in fructose malabsorption. Fructans-rich foods are: wheat (white bread, pasta, pastries, cookies), onions, and artichokes; other not commonly problematic foods with fructans are asparagus, leeks, garlic, chicory roots and chicory based coffee substitutes. Fructans with over 10 molecules of fructose in a chain are known as inulins and those with less than 10 fructoses are referred as fructo-oligosaccharide (FOS) or oligofructose. Fructans cause problems mainly in fructose malabsorption.
    • Galactans (like stacchyose and raffinose) are chains of galactose molecules with one fructose molecule on the end. They act much like fructans. Main galactans-rich foods are legumes (soy, beans, chickpeas, lentils), cabbage and brussel sprouts.
  • Disaccharides:
    • Lactose (milk sugar). Lactose is in dairy products, but it may be also found in chocolate and other sweets, beer, pre-prepared soups and sauces, and so on. Lactose is poorly absorbed in lactose intolerance, SIBO and in small intestinal inflammation (Crohn’s disease, celiac disease).
  • Monosaccharides:
    • Fructose (fruit sugar). Fructose-rich foods are honey, dried fruits like prunes, figs, dates, or raisins, apples, pears, sweet cherries, peaches, agave syrup, watermelon, papaya. Fructose is often added to commercial foods and drinks as high fructose corn syrup (HFCS). Fructose causes symptoms even in healthy people, if ingested in excess, especially in fructose malabsorption, but also in SIBO.
  • Polyols, also known as sugar alcohols (appearing as artificial sweeteners in commercial foods and drinks):
    • Sorbitol  may appear in “sugar-free chewing gum”, “low calorie foods”; naturally it appears in stone fruits: peaches, apricots, plums).
    • Xylitol naturally appears in some berries. A pack of chewing gum containing sorbitol or xylitol may cause bloating or diarrhea in a healthy child and especially in persons with fructose malabsorption or SIBO.
    • Other polyols, like mannitol, isomalt, erithrytol, arabitol, erythritol, glycol, glycerol, lactitol, ribitol, may be problematic in fructose malabsorption and SIBO.

Approach to a Low-FODMAPs Diet

In unexplained chronic diarrhea or bloating, FODMAPs should be considered as a possible cause, so their amount in the diet should be LIMITED (not necessary totally excluded).

General approach is to take off as much as possible FODMAPs from the diet for six to eight weeks. If FODMAPs are the cause of the symptoms, they should lessen considerably in the first week. Additional weeks of diet bring some rest to the small intestine and cause reduction of overgrown intestinal bacteria.

After six weeks, some foods that will least likely cause symptoms can be introduced back into the diet (diet challenge), one type of food every fourth day. For example, on the first day of the seventh week, a piece of food low in lactose, like yogurt, can be tried, and if in the next 72 hours no symptoms appear, other dairy products can be tried, and waited 72 hours again. If still no symptoms, it is not likely that dairy is problematic, or at least not problematic when taken in a limited amount. If symptoms appear, this speaks for lactose intolerance, so dairy should be avoided and next type of foods tried. This can be some low-fructose food like banana, then after 72 hours orange and then other foods with increasing amount of fructose. If you can eat 5 prunes in a row without having abdominal symptoms thereafter, it is not likely you have fructose malabsorption.

A registered dietitian may be needed to give instructions about introduction of the low-FODMAP diet and diet challenge.

Possible Symptoms of a FODMAP-Rich Diet

Excessive FODMAPs intake may cause:

  1. Diarrhea, since FODMAPs are osmotically active, so they drag water from the intestinal vessels into the intestine
  2. Bloating and flatulence, since FODMAPs are broken down (fermented) by intestinal bacteria to gases like hydrogen, carbon dioxide or methane
  3. Excessive belching (burping)
  4. Abdominal pain
  5. Unintentional weight loss
  6. Symptoms of vitamin and mineral deficiency, like paleness, tingling, tiredness, depression
  7. Headache

FODMAPS may also aggravate symptoms of:

How Long Should a Low-FOODMAP Diet Last?

When problematic FODMAPs are identified, some people will need to strictly avoid them for life, if they want to be symptoms free, others will be able to ingest them in a limited amount. General rule is: do not eat FODMAPs-rich foods in large amount in one sitting and do not eat them every day.

If Low-FODMAP diet does not lessen your abdominal symptoms, consider having tests for food allergies, dumping syndrome, celiac disease, and inflammatory bowel disease (Crohn’s disease).

Can a Low-FODMAP Diet Be Dangerous?

Low-FODMAP diet should not be introduced by any person with diabetes, hypoglycemia or other metabolic disorders, or in malnutrition, without prior consultation with a doctor. It may be necessary to interrupt Low-FODMAP diet in any severe acute disease, after injury or surgery and in other urgent situations.

None of FODMAPs (fructans, galactans, fructose, lactose, polyols) is essential nutrient for human, though, meaning they are not necessary for life.

Foods to Avoid in IBS

Foods that irritate individuals diagnosed with IBS, differ from person to person. It was found out that in many of them FODMAPs-rich foods are the culprit (1).

Related Articles:


  1. Low-FODMAP diet (healthsystem.virginia.edu)
  2. Polyols – sugar alcohols (sugar.org)
About Jan Modric (249 Articles)
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  • Jan Modric


    bloating, sugar craving and large amount of mucus may occur in intestinal parasites, and small intestinal bacterial overgrowth (SIBO). SIBO can be a complication of certain food intolerance, such as fructose malabsorption, lactose intolerance or celiac disease. I can’t exclude food allergy, but this sounds less likely to me.

    Food intolerances such as fructose malabsorption and lactose intolerance may be standalone conditions or can be caused by intestinal inflammation caused by a celiac or Crohn’s disease. Tests for all mentioned disorders are available. Few days lasting diet trials are also available: lactose-free diet for lactose intolerance, low-fructose diet for fructose malabsorption, gluten-free diet for celiac disease, and low-FODMAP diet for IBS. But, when you have SIBO, diets alone may not help at all, and SIBO needs to be treated first (with antibiotics).

    I really don’t know which test you should try next, but you can visit an experienced gastroenterologist and discuss with him/her about:
    – breath test for SIBO, fructose malabsorption and lactose intolerance
    – blood test for celiac disease
    – regarding 4 years history of your symptoms, intestinal parasites are less likely
    – food allergy, to me, also sounds less likely, but a good doctor should know which tests to order first

  • Vanessa

    Hi Jan thankyou so much for your help. Could you please advise me on what antibiotics I should ask for.
    Many thanks

  • Jan Modric


    first, the doctor should decide will he/she order a test for SIBO, and if SIBO will be confirmed, he/she will decide which exact antibiotic to prescribe.

  • Skip

    I was diagnosed with Fructose Malabsorption and have been diet compliant for over a year. My weight has fluctuated from day to day, but now I am rapidly putting on weight – no matter how much I limit my food. I only eat eggs, chicken, plain unsweetened whey protein, white rice, spinach, white potato, lettuce, snow peas, snap beans, grits, butter, oatmeal, olive oil, plain popcorn, pumpkin seeds, peanut butter (limit of 1 TBSP/day), Trader Joe’s O’s cereal. Water is my only beverage. I have tried Peptamen Plain, hoping for a food substitute but get severe abdominal pain after only 1/2 a serving.
    So here’s my question: What mechanism can make someone with a malabsorption disorder GAIN weight, even if very little food is eaten? I really need help. Thank you

  • Dr. Chris

    Hi Skip

    This question has been answered on Health Hype Answers (link below)

  • Pam

    Hi Skip,

    If you are not eating enough calories while on a low Fodmap diet or are eating to many calories you can put on a lot of weight regardless if you are eating less food.

    If you are not eating enough your body maybe going into starvation mode.
    If you are eating to many calories even though you are eating a little then this may cause weight gain.
    I have fructose malabsorption intolerance also and I notice when I am not being strict with my diet I put on a lot of weight.
    If I watch what I eat and stick to my calorie controlled diet my dietian had set out for me, with regular exercise then I seem to be able to loose weight approx 3 kilos a week.
    If I don’t stick to my Low Fodmap diet and don’t watch my calories then my weight can increase greatly.
    It seems in Fodmap intolerant people our metabolisms do not work like normal and if exercise is not a large part of your recovery or health regime then we can suffer more.
    I have suffered from this for the past year and find that weight control is something that will be part of this intolerance.

  • Sick of it

    Hi, Ive had problems with my stomach since I was a teen, in particularly a couple of years after I started menstruating. I’ve had every test done known to man to be told time and time again it’s IBS! I’m 36, so been putting up with this since I was 12/13 years old. I’ve had several endoscopies and colonoscopies over the years all came back with the result – it’s IBS. I had my appendix removed and part of my bowel cause it had wrapped itself around my appendix at the age of 15. I have also suffered from reflux for as long as I can remember and I am on Losec 20mg twice a day (for the rest of my life so I have been told). I was diagnosed as lactose intolerant in my early teens but over the years can now stomach a little milk,cheese and yoghurt. I cannot stomach onions in the last year and garlic can upset my stomach as well. I have not been able to stomach spicy foods, oregano, coconut milk, curries, rich cheeses, to name a few since being diagnosed with IBS. I seriously C R A V E CHOCOLATE and sweet things daily, especially in the evenings, when I have been exercising or busy at work (feeling flat)and around that time of the month. I have never had this breath test you are talking about for SIBO, fructose malabsorption and lactose intolerance. My blood test results for celiac disease came back negative. I suffer from anxiety attacks, depression and very painful periods and I have been overweight all my life. I seem to have “very bad attacks” of IBS at least 4 -6 times a year. I am currently having an attack and i’ve been in agony now and off work for 15 days!!! Started off with diahorrea for 3 days than constipation. Bloating, gas, extremely tender lower left side of tummy. Thought I had Diverticulitis, was put on Flagyl. Spent nite at hospital last weekend. Bloods – normal, urine – normal, xray – showed I was constipated with parts of bowel inflammed. CT scan/ Barium meal on Monday just gone – not diverticulitus! Been on enimas last two nights to get things moving again. Tummy still bloated,tender and in pain. Can anyone P L E A S E tell me what they think is going on with my tummy as I am SERIOUSLY OVER ALL OF THIS!!!! My latest Doc things I may have an intolerance to gluten and has suggested seeing a dietitian for FODMAP diet. He’s stumped!

  • Sick of it

    Is this site still active? Is anyone still answering questions or giving feedback? Anxiously awaiting reply ……:(

  • Dr. Chris

    Hi Sick of It

    Responses from the Health Hype team are not instantaneous. It may take anywhere between 3 to 7 days. Even responses from other users will only be live once it is screened and approved. If you need urgent assistance, you should speak to a health care professional. Alternatively you can click on Ask a Doctor Online link above (if active) and have an online chat with a doctor immediately (paid service). This comment/question-answer platform that you are using is a free service and only intended to guide readers but not serve as a medical consultation or means of diagnosing, prescribing or managing a condition.

  • Sick of it

    Thanks Dr. Chris. I understand what you are saying was just waiting to hear someone elses point of view that understands it all. Nearly every Doctor I have seen has just put it down to IBS – not to many know about the FODMAP stuff. I’ll keep checking back for other comments…. Thank you

  • Dr. Chris

    Hi Sick of It

    Much of your symptoms are indicative of IBS. In fact a diagnosis of IBS can be made based on the fact that no other pathology has been detected. Even the infections should not distract from the fact that the underlying problem can be IBS. Remember that a diagnosis of IBS does not entirely mean that no doctor knows what is wrong and is just chalking it down to IBS. There may be a disruption in gastrointestinal motility which is not linked to any underlying disease – if it is faster than normal then it may give rise to diarrhea-predominant IBS while with slower than normal motility it may be constipation-predominant IBS. Certain foods, stress, depression and so on are known to exacerbate IBS. A FODMAP diet MAY therefore help but this is not a guarantee that it.

    Gluten intolerance is a separate and specific condition than should be diagnosed with proper investigation. Until this has been conclusively established, there should be no assumptions about it being a factor in your case. I say case because it is unlikely that all your symptoms can be chalked down to a single disorder here.

    Patients with chronic gastrointestinal problems often are not satisfied with a diagnosis of IBS. But it is debilitating condition which is present with no underlying detectable pathology. Until you tend to a few of the problems that you mentioned, there is no way to exclude IBS for sure – seek help for your anxiety/depression, ascertain the cause of painful periods (contrary to popular belief period pain is NOT the norm, there may be mild discomfort but actual pain indicates possible underlying pathology like PCOS) and weight control is essential. You may be surprised to find that many of your GI symptoms will resolve or your IBS will come under better control.

    Nevertheless, you should have this investigated further. You need to see a gastroenterologist who can work with you in the long term. Conduct different tests to exclude other pathology that may have not been detected as yet. Elimination diets and a FODMAP diet won’t do any harm and is definitely worth a try. If you have not done so already, you should keep a food diary where you record the food you ate, symptoms, general state of wellbeing and so on on a daily basis. This is of huge benefit when assessing your case and verifying your history.

  • Kelly Herzog Kerchner

    I love to go to [BRAND REMOVED] and have the chicken strips (without breading) and medium sauce. Can you tell me if any of these ingredients are ok? I can’t seem to find a low fodmap list of ingredients that are not food. Thanks! margarine, water, salt, soy lecithin, natural flavor, vegetable mono and diglycerides, annatto and tumeric, vitamin A,palmitate, whey, soybean oil, cayenne pepper, vinegar, brown sugar, sald, water, mono and diglycerides, sodium benzoate.

  • Hi Kelly. We cannot comment on the specific food in question. In all likelihood it should be fine but we are not privy to the recipe of the restaurant in question. I think you may have some misconceptions about certain ingredients. Vitamin A for example is not an ingredient that you can add into food but rather a micronutrient that is present in certain foods in varying quantities. Of course, vitamin A itself is not a problem but the foods that it may be within could be problematic. Best you consult with a dietitian/nutritionist in your area who can advise you further.