By Joe Schreiber

What is the FODMAP diet?

The low FODMAP diet (colloquially, FODMAPs) is a relatively new diet founded by Monash University. It is one of the most sound and conclusive methods to successfully combat pain and discomfort from IBS and IBD. It is not only useful as a diet for the relief of digestive conditions, but as a system to identify what foods are individually problematic.

What does FODMAP stand for?

The term FODMAP was first used in a 2005 opinion and theory piece about the influence of environmental factors, as opposed to genetic, on the development of Crohn’s disease.1 Westernization was already thought to be tied to Crohn’s, and food was a natural suspect. It was a perfect example of a modern lifestyle causing havoc across digestive systems through things we should have already known not to eat. The article, by Peter Gibson of Monash University, posited that excess short-chain carbohydrates, tiny carbs found in foods, were a central cause of all our digestive problems.

He named them Fermentable Oligo-, Di-, Mono-saccharides and Polyols, FODMAPs.

FODMAPs are short chain carbohydrates. In comparison to long chain carbs such as glucose, they consist or only a few linked sugars. FODMAPs take more effort for our small intestine to digest, and can cause discomfort in certain conditions such as colitis and Crohn’s. FODMAPs include fructose, a simple sugar found in fruits, vegetables, and other sugary foods; lactose, a carbohydrate found in dairy; fructans, found alongside gluten and vegetables such as artichokes and onions; galactans, found in legumes; and polyols, found in some fruits and vegetables as well as artificial sweeteners such as sorbitol and xylitol that are used to lower caloric content.

FODMAPs and the gut

Helpful gut bacteria sit in the front of the intestine and turn foods into methane. FODMAPs are more difficult for that bacteria to digest and usually reach the end of the intestine, where the bacteria of the distal small intestine and proximal large intestine rapidly ferment them into hydrogen before they can escape. It’s not quite a hive of scum and villainy as these bacteria aren’t criminals – they simply doing their jobs. The culprit here is the western diet and our genes. Modern diets cause us to consume far more FODMAPs than the bacteria in the front of our intestine are trained to handle, so the rest must quickly digest the excess and produce unusually high volumes of hydrogen. On top of that, many of us have a unique genetic disposition that causes our bacteria to doze off in class and become less effective at processing certain foods, if at all. This can be a common genetic issue, but is certainly more common in IBS. For many of us they may not be the villains, but they are certainly corrupt.

The hydrogen produced from the fermentation of excess FODMAPs leads to increased intestinal permeability, which contributes to the development of IBS and IBD.2 Excess hydrogen causes many familiar IBS and IBD symptoms, such as gas, distention of the gut, bloating, cramps, constipation, and pain. On top of those, FODMAPs are often partially absorbed or not absorbed at all, and bring excess water into the intestine through osmosis, which causes diarrhea.

The paper suggested that the Western diet and our own personal biology lead to two issues worth researching, which foods and what quantities of them will lead to adverse conditions. The researchers at Monash launched a long-term and exhaustive investigation into testing and retesting exactly how much of which food is too much. The low FODMAP diet is derived from this information and will help you perform your own investigation to solve the mystery of who is hurting your intestines and causing your IBS or IBD. The answer may surprise you. Is it a network of fruits and vegetables forming an unlikely criminal network after decades of feuding? Is it the notorious gluten crime family? Or maybe… it was the beans all along.

How do you carry out this diet?

As IBS and IBD have taught us all, not everyone reacts the same to everything. One of the most useful things about FODMAPs, is that it’s a restrictive diet. Once you have eliminated every FODMAP for a few weeks and seen results, you can enter what is called the challenge phase, and gradually start reintroducing eliminated food for a few days to see if IBD or IBS symptoms begin to creep back into your guts, and if they do you’ve caught them in the act. You can determine if a specific food is causing you problems and decide if it should be removed permanently or partially. While you can attempt restricting different FODMAPs on your own, it may save you some time if you consult with a doctor or dietician, who can test to confirm whole groups of foods or FODMAPs to avoid, such as fructose and lactose, and help you manage your diet. You should discuss the diet with a professional regularly.

FODMAPs is the most promising non-medical therapy for IBS and IBD and has no direct side effects. 75% of IBS cases benefit from a low FODMAP diet, often significantly. Even though the early FODMAP research was for treating Crohn’s disease, it is more successful in treating IBS than IBD. If you have Crohn’s, ulcerative colitis or pancolitis, there is a 50% chance it will significantly benefit you. The diet is supported by over ten years of research at Monash University, who constantly research new findings and retest old ones.

If you do not have an IBS or IBD, or a related condition, the low FODMAP diet will be a complete waste of your time and energy. If you have IBS or IBD, no other conflicting factors, and a lifestyle that will not interfere with the diet or your adherence to it, you may want to give the low FODMAP diet a try.

High FODMAP foods

While researching this list, we discovered a lot of contradictory, out of date, and sometimes incorrect information. We strive to keep our information to the highest standards, and found that one significant reason for this misinformation was that many foods have certain thresholds of daily consumption, that will lead to problems. When interpreting this data, many sites choose to classify only as low or high FODMAP foods, which can lead to contradiction. In our list, we are defining both low and high FODMAP foods, but foods marked by an asterisk* can be consumed in significant amounts, and will be listed with an appropriate volume in the Moderate FODMAP Foods section.

FruitsVegetablesGrains and nutsDairySweets and sweetenersAlcoholOther
Apples (all varieties, except apple cider vinegar)Artichoke (one serving of canned artichoke hearts is fine)Almonds*ButtermilkAgaveRumKetchup
Bananas (ripe)AsparagusAmaranth flourCustardFructose
BlackberriesAdzuki beansBarleyKefirHigh-fructose corn syrup (HFCS)
BlackcurrantsBaked beansBranMilkMolasses
Blueberries*Beetroot (fine when pickled or canned)CashewsYogurtInulin
Boysenberries*Black beansCoconut flourIsomalt
CherriesBroad beansCouscousLactitol
Cranberries (juice is fine)Broccoli heads and rabeEinkorn flourMaltitol
CurrantsBroccolini (should be avoided as a whole, but the stalks are safe)FreekehMannitol
DatesBrussels sproutsGranolaSorbitol
FeijoasButter beansMuesliXylitol
FigsButternut squashPistachios
Goji berriesCauliflowerRye
Guava (unripe)ChickpeasSpelt (some breads are low FODMAP)
Lychee (all varieties)*Fava beansTahini
MangosGarlicWheat germ
NectarinesHaricot beans (navy beans)Wheat pasta
PeachesJerusalem artichokeWheat noodles
PearsKidney beans
Pineapple (dried)Lima beans
PlumsMung beans*
Pomegranates*Mushrooms (all but oyster and canned)
PrunesOnions (also when pickled)
RaisinsSavoy cabbage*
SultanasScallions and spring onions
WatermelonSnow peas
Soya beans
Split peas
Sugar snap peas (mange tout)

FODMAP categories

If you find that you react to one FODMAP more than others, this list will help intuitively understand what foods and FODMAPs you should personally avoid.

Oligos (fructans and GOS)FructosePolyolsLactose
Almonds*AsparagusApples (all varieties, except apple cider vinegar)Buttermilk
Artichokes (one serving of canned artichoke hearts is fine)Balsamic vinegar (moderate at 2 tbsp)Bell peppers (green)*Custard
Adzuki beansBroad beansCauliflowerMilk
Baked beansBroccoli heads and rabeCeleryYogurt
Bananas (ripe)Broccolini (should be avoided as a whole, but the stalks are safe)Cherries
Beetroot (fine when pickled or canned)Fava beansLychee*
Black beansFeijoasMangos
BlackcurrantsFigs (fresh)Nectarines
BranJerusalem artichokesPears
Brussels sproutsPearsPlums
Butter beansRye (the grain)Prunes
Butternut squashRumSauerkraut
CashewsSultanasSnow peas
ChickpeasTamarillosSugar snap peas (mange tout)
Cranberries (juice is fine)Wheat noodles
Einkorn flour
Figs (dried)
Goji berries
Haricot beans (navy beans)
Jerusalem artichokes
Kidney beans
Lima beans
Mung beans*
Pineapple (dried)
Savoy cabbage*
Snow peas
Soya beans
Spelt (some breads are low FODMAP)
Split peas
Sugar snap peas (mange tout)
Wheat germ
Wheat pasta
Wheat noodles

Moderate FODMAP Foods

Avocado (1/4 of a whole avocado)Bell peppers (green) (moderate at 1 serving)Almonds (10 nuts)Ice cream (moderate at 1 serving)Balsamic vinegar (moderate at 2 tbsp)
Bananas chips (more than one serving size, about 15 chips)Broccoli (whole) (moderate at 3 cups)
Bitter melon (1/4 cup)Cabbage
Blueberries (moderate at 2/3 cup)Garbanzo beans (moderate at 1/2 cup)
Grapefruit (moderate at 1/2 cup)Jicama (moderate at 1 1/4 cups)
Melon (moderate at 2/3 cup)Lentils (moderate at 1/2 cup)
Quince (moderate at 1 tbsp)Mung beans (fine at 1/4 cup)
Passionfruit (moderate at 2 servings, about 4 fruits)Savoy cabbage (moderate at 3/4 cup)
Pineapple (fresh: 1 1/4 cup, dried: 1/8 cup)Zucchini (moderate at 1/2 cup)
Pomegranate (moderate at 1/3 cup)
Raspberries (moderate at 35 berries)

Low FODMAP foods

FruitsVegetablesSeasonings and spicesDairyAlcohol (try to limit to one drink and with food)Other
DragonfruitAlfalfaAllspiceCheese (all)BeerLicorice (bonus: licorice is also good for IBS!)
Grapes (all)ArugulaAniseCream cheeseWineMayonnaise
Guava (ripe)Bamboo shootsBasilWhipped creamVodkaMustard
Kiwi (no more than 1 serving)BasilBay leavesCottage cheeseWhiskeyOils
Oranges (juice is high FODMAP)Bay leavesCardamonRegular fat creamGinVinegar (except balsamic)*
Passionfruit (no more than 1 serving)Bean shootsChiliesMayostard
StarfruitBean sproutsCinnamonMustardayonnaise
StrawberriesBroccoli (stalks only)Cloves Mustmayostardayonnaise
TamarindBok choy (no more than 1 serving)Coriander
Cabbage (no more than 1 serving)Curry powder
CardamonFennel seeds
Cassava (no more than 1 serving)Lemongrass
Chard/silver beetMint
Chayote/chokos (no more than 1 serving)Mustard seeds
Chilies (beware, chilis may offend your IBS in general)Paprika
Choy sumParsley
CinnamonPeppercorns (black, white, red, green)
ClovesPoppy seeds
Collard greensRosemary
Curry leavesStar anise
Eggplant (no more than 1 serving)Tarragon
EndivesThai basil/holy basil
Fennel seedsThyme
Green beans
Kaffir lime leaves
Lentils (canned)
Mushrooms (canned)
Okra (no more than 1 serving)
Oyster mushrooms
Pandan leaves
Peppercorns (black, white, red, green)
Poppy seeds
Red bell peppers
Red cabbage (no more than 1 serving)
Sesame seeds
Spinach (baby spinach is moderate)
Squash (acorn, buttercup, delicata)
Summer squash
Sweet potato/yams (no more than 1 serving)
Swiss chard
Taro (no more than 1 serving)
Thai basil/holy basil

Treatment of SIBO

A low-FODMAP diet is also one of the crucial intervention steps in the treatment of Small Intestinal Bacterial Overgrowth (SIBO). Read much more on that here.

  1. Gibson, P. R. and Shepherd, S. J. (2005), Personal view: food for thought – western lifestyle and susceptibility to Crohn’s disease. The FODMAP hypothesis. Alimentary Pharmacology & Therapeutics, 21: 1399-1409. doi:10.1111/j.1365-2036.2005.02506.x
  2. See our excellent article about the carnivore diet for more information about intestinal permeability

Joe Schreiber