Updated November 2019

What are FODMAPs?

“FODMAP” refers to short-chain carbohydrates found in food that are rapidly fermented by gut bacteria (1). 

It is an abbreviation for:


Types of FODMAPs

Here’s a more detailed explanation of each type of FODMAP:

1. Monosaccharides

A monosaccharide is the simplest form of sugar, made up of a single molecule. 

Monosaccharides act as the building blocks of all carbohydrates (2).

There are 3 main types:

    • Glucose
    • Fructose
    • Galactose

Fructose is the only monosaccharide considered a FODMAP.

2. Disaccharides

These carbohydrates are formed when 2 monosaccharides bond together (2). 

There are 3 main types of disaccharides: 

    • Maltose (glucose + glucose)
    • Sucrose (fructose + glucose)
    • Lactose (galactose + glucose)

Lactose is the only disaccharide considered a FODMAP.

3. Oligosaccharides

These carbohydrates are made up of a small number of monosaccharides (usually less than 20) (3).

There are many types of oligosaccharides, but two are considered FODMAPs (4):

    • Fructooligosaccharides (FOS), also known as fructans
    • Galactooligosaccharides (GOS), also known as galactans

4. Polyols

These carbohydrates are also known as sugar alcohols because their chemical structure resembles both sugar and alcohol (5).

Some polyols, such as sorbitol and mannitol, are found naturally in food, but others are man-made and used as artificial sweeteners.

All polyols (natural and synthetic) are considered to be FODMAPs.

The most common polyols in food are:

    • Erythritol
    • Isomalt
    • Lactitol
    • Maltitol
    • Mannitol
    • Sorbitol
    • Xylitol

Are FODMAPs a health concern?

FODMAPs are not a health concern for MOST people. 

In fact, certain FODMAPs (mainly fructans and galactans) are generally considered to be health-promoting, because they act as prebiotics (6).

However, in some people (especially those with IBS), they may exacerbate GI symptoms (bloating, gas, diarrhea) (1).

How do FODMAPs cause symptoms? 

FODMAPs can contribute to symptoms in a variety of ways:

1. They can be poorly absorbed in the small intestine.

    • Fructose is slowly absorbed when present in larger quantities than glucose, which can lead to incomplete absorption (1, 7).
    • Lactose must be broken down by the lactase enzyme in order to be absorbed, but some people have a lactase deficiency (1, 8).
    • FOS and GOS cannot be broken down and absorbed, because humans do not produce the necessary enzymes (1). 
    • Polyols are absorbed by passive diffusion, but their larger size makes this process more difficult (9, 10). 

2. If not fully absorbed, they can draw water into the intestines.

FODMAPs that aren’t absorbed continue to move through the GI tract, where their presence draws water into the intestines (1, 11). 

This process occurs through osmosis, the movement of water from a region of lower solute concentration to a region of higher solute concentration (12).

Excess water in the intestines causes them to expand, which can result in abdominal pain and bloating and contribute to diarrhea (1).

3. They are rapidly fermented by gut bacteria.

Because FODMAPs are made up of short carbohydrate chains, they are easier for bacteria to ferment compared to polysaccharides, which have longer chains (10, 13).

When unabsorbed FODMAPs enter the colon, gut bacteria can ferment (metabolize) them. 

This leads to the production of large amounts of gas (hydrogen, carbon dioxide, and methane), which can cause bloating and abdominal pain (1).

4. They may increase intestinal inflammation and gut permeability.

New animal research has found that a high-FODMAP diet can increase the number of gram-negative bacteria in the gut, increase LPS levels, and increase intestinal inflammation and permeability (14). 

Interestingly, these effects were prevented by antibiotics (Rifaximin) and reversed by the low-FODMAP diet (14).

What are the criteria for high FODMAP foods?

Foods are considered to be “high-FODMAP” if they meet the following criteria (15):

Individual FODMAPs Grams per standard serving size
Oligosaccharides (grains, legumes, nuts & seeds) >0.30
Oligosaccharides (vegetables, fruits, and all other products) >0.20
Polyols (sorbitol or mannitol) >0.20
Total polyols >0.40
Excess fructose >0.15
Excess fructose (for fresh fruit & vegetables when “fructose in excess of glucose” is the only FODMAP present) >0.40
Lactose >1.00

What is the low-FODMAP diet?

The low FODMAP diet is a short-term elimination diet, in which high-FODMAP foods are temporarily removed and then slowly added back in, one at a time, in order to determine which types of FODMAPs trigger symptoms for the individual. 

It consists of 3 phases (elimination, reintroduction, and personalization) and takes about 8-16 weeks to complete.

Who might benefit from a low-FODMAP diet?

People with the following conditions may benefit from trying the low-FODMAP diet:

1. Irritable Bowel Syndrome (IBS)

There is a large body of evidence showing that 50%-80% of patients with IBS report improved symptoms while on a low-FODMAP diet for up to 6 months (16, 17, 18, 19, 20, 21, 22, 23).

However, several systematic reviews have found the quality of evidence to be “very low” due to a high risk of bias and lack of long-term studies (24, 25).

Still, adherence to the diet and patient satisfaction is relatively high.

In one study, 80% of people with IBS who tried the low-FODMAP diet were still following a personalized version after nearly 2 years and had significantly less abdominal pain than those who stopped the diet. 89% were satisfied with their experience (26). 

2. Inflammatory Bowel Disease (IBD)

There is some evidence that the low-FODMAP diet might improve IBS-like symptoms and reduce intestinal inflammatory markers (calprotectin) in patients with IBD (27, 28, 29, 30, 31, 32).

One study found that symptoms were exacerbated by fructans but not GOS or sorbitol in these patients (33).

More research is needed since not all studies have found significant effects (34).

3. Small Intestinal Bacterial Overgrowth (SIBO)?

Some practitioners theorize that a low FODMAP diet may be helpful for people with SIBO (small intestine bacterial overgrowth). 

Theoretically, reducing consumption of highly fermentable fibers may reduce symptoms since there will be less “food” for the bacteria in the small intestine. 

However, no clinical trials have evaluated its use and effectiveness for this population (35).

4. Non-Celiac Gluten Sensitivity?

One study found that a low-FODMAP diet reduced symptoms for people with non-celiac gluten sensitivity (although a traditional gluten-free diet was more effective) (36).

5. Exercise-Induced Gastrointestinal Symptoms

Several studies have found that following a low-FODMAP diet can significantly reduce exercise-related GI symptoms in recreational athletes and ultramarathoners (37, 38, 39).

6. Fecal Incontinence

One small, non-controlled study found that 65% of people with fecal incontinence experienced a reduction in symptoms while on the low FODMAP diet (40).

Nearly 35% of those people had a complete recovery, while another 40% had at least a 75% improvement (40).

7. Infantile Colic

A 2018 randomized control trial found that breastfeeding infants experienced 32% less colic while their mothers were following a low-FODMAP diet, but the mechanisms are not clear (41).

8. Radiation-induced enteropathy?

A small pilot study found preliminary evidence that a low-FODMAP diet can reduce IBS symptoms in people with radiation-induced enteropathy (42).

More follow-up research is needed.

Future Directions

Researchers are trying to evaluate whether gut microbiota profiles impact people’s responses to a low-FODMAP diet (43).

If we can use stool samples to determine who is most likely to benefit from a low-FODMAP diet, it may greatly improve treatment outcomes.

Based on one preliminary study, responders tended to have more Bacteroides fragilis, Acinetobacter, Ruminiclostridium, Streptococcus, and Eubacterium and less Clostridia/Negativicutes/Bacilli, Actinomycetales, Anaerotruncus, Clostridiales, and Shigella/Escherichia (43).

Are there any side effects or precautions?

1. Malnutrition

There is some concern that the low-FODMAP may increase the risk of malnutrition due to the restriction of so many foods.

However, thus far, the research has not really supported this concern.

One short-term study found that 8 weeks on the low-FODMAP diet had no effect on body composition or nutritional status (44).

Several other studies have found minor differences in micronutrients between “regular” and low-FODMAP diets after controlling for changes in energy intake (45, 46, 47).

More studies are needed to determine whether the low-FODMAP diet increases the risk of malnutrition over a longer time period. However, it is important to remember that the elimination stage of a low-FODMAP diet is only meant to be followed for a short time period, then tolerated foods should be reintroduced.

It is recommended that all patients work with a FODMAP-trained dietitian who can ensure nutritional adequacy and guide them through the phases of the diet (48, 49, 50).

2. Altered gut bacteria

Several studies have shown significant reductions in beneficial gut bacteria in patients with IBS or non-celiac gluten sensitivity after 3-4 weeks on a low-FODMAP diet (36, 51, 52).

Taking a multi-strain probiotic (VSL#3, two sachets per day, in the morning with food) while following a low-FODMAP diet may help increase “good” Bifidobacteria without increasing symptoms (53).

Another study found that taking a Bacillus coagulans supplement (Ganeden BC30) daily for 8 weeks in addition to following the low-FODMAP diet was more effective at reducing IBS symptoms than the diet alone (54).

3. Eating disorders

A recent study found that greater adherence to a low-FODMAP diet was associated with eating disorder behavior in patients with IBS (55).

However, there was no follow-up to determine whether these patients actually met the diagnostic criteria for eating disorders (55, 56).

Recent commentary suggests that some of the questions used in the study may be a reflection of how people with IBS relate food with their symptoms, rather than classic disordered eating (57).

4. Special considerations for children

Implementing “healthy eating” practices (Harvard Healthy Eating Plate) can reduce IBS symptoms in some children. This intervention may be worth trying before embarking on more complex protocols like the low-FODMAP diet (58).

5. Special considerations for enteral nutrition

Homemade enteral nutrition recipes can include milk, orange juice, or apples, which are high in FODMAPs. Consider altering the recommendations for people with intestinal sensitivity or GI symptoms (59).

How to Implement the Low FODMAP Diet (60, 61, 62)

The low FODMAP diet is a short-term elimination diet, in which high-FODMAP foods are temporarily removed and then slowly added back in, one at a time, in order to determine which types of FODMAPs trigger symptoms for the individual. 

Phase 1: Elimination (2-6 weeks)

During this phase, only low-FODMAP foods are consumed. The goal is to eliminate symptoms.

Use the Monash app to determine which foods/portion sizes are considered “low-FODMAP”, then plan your diet accordingly.

This allows people to customize their low-FODMAP diet in accordance with their personal dietary preferences.

  • Open the Monash app and click “Food Guide”.
  • Select the category of foods you’d like to review the FODMAP content of.
  • Click on an individual food.
  • You will see which portion sizes are considered low, medium, or high FODMAP and which type of FODMAP(s) the food contains.
  • Only include low-FODMAP foods during the elimination phase.

The Monash app is updated frequently, includes vital information about portion sizes, and is generally considered the best resource for patients and practitioners.

Phase 2: Reintroduction (6-10 weeks)

Next, high-FODMAP foods are slowly reintroduced, one type at a time, to determine which types of FODMAPs are triggering symptoms.

A food-symptom journal is used to track what foods (and portion sizes) are consumed when and when any symptoms occurred. Click here to download a free copy of our FODMAP reintroduction worksheet.

Sample Reintroduction Plan (61)
FODMAP being tested Timeline Recommended foods to try (portion size to build up to)
Fructose Week 1, Day 1-3 Honey (1 tsp) OR mango (½)
Week 1, Days 4-6 Washout period
Lactose Week 2, Day 1-3 Milk (½ cup) or yogurt (7 ounces)
Week 2, Day 4-6 Washout period
Sorbitol (polyol) Week 3, Day 1-3 Avocado (⅓-½) or apricot (1 small)
Week 3, Day 4-6 Washout period
Mannitol (polyol) Week 4, Day 1-3 Mushroom (½ cup) or cauliflower (½ cup)
Week 4, Day 4-6 Washout period
Fructose + Sorbitol* Week 5, Day 1-3 Apple (½) or pear (½)  
Week 5, Day 4-6 Washout period
Fructan (wheat)** Week 6, Day 1, 3, 5 Whole wheat bread (1 slice) or pasta (1 cup)
Week 6, Day 6-7 Washout period
Fructan (onion/garlic)** Week 7, Day 1, 3, 5 Onion (1 ring) or garlic (¼-½ clove)
Week 7, Day 6-7 Washout period
GOS** Week 8, Day 1, 3, 5 Lentils (½ cup) or chickpeas (2 tbsp)
Week 8, Day 6-7 Washout period
*Only complete if both fructose and sorbitol challenges were passed.

**Fructans and GOS may be better tolerated if challenged every other day at first, and then (if well tolerated) challenged again on consecutive days.

Peer-reviewed research regarding the best way to reintroduce FODMAPs is lacking, but most practitioners follow these general guidelines:

    • Introduce no more than one FODMAP subgroup per week.
    • If a patient suspects a certain FODMAP group is responsible for symptoms, then challenge that group last.
    • When reintroducing each type of FODMAP, choose foods that only contain that type of FODMAP (i.e. don’t use foods that contain multiple types of FODMAPs during the reintroduction phase, unless doing the fructose + sorbitol challenge).
    • Eat the challenge food for 2-3 days in a row (increasing from small to normal portion sizes) during the test week.
    • If symptoms arise, stop consuming that type of FODMAP and allow for a 2-3 day washout period (or until symptoms fully resolve) before trying a new food.
    • Once a specific type of FODMAP has been tested, remove it from the diet again (even if it was tolerated) until all FODMAP groups have been tested individually. 

If you don’t get symptoms during an initial test of a specific high-FODMAP food:

    • Keep increasing the amount of food until you reach your desired portion size.
    • Try another food in the same FODMAP group to confirm your results.

If you do get symptoms:

    • Stop challenging the food.
    • Wait until you are symptom-free, then reduce the serving size to half and challenge again.
    • Try another food from the same FODMAP group to confirm your results.

3. Personalization Phase (long-term)

After finishing the reintroduction phase, patients who have determined which FODMAPs are tolerated can add those foods back into their diets. 

Foods containing FODMAPs that weren’t tolerated should continue to be restricted, but re-challenging foods from time-to-time is recommended, as tolerance can change.

Low-FODMAP Diet Tips

1. Use the Monash app.

The Monash University Low FODMAP Diet app (paid) is the best way to stay up-to-date on which foods are low and high in FODMAPs.

It also includes low FODMAP recipes and a FODMAP Diet Guide booklet.

2. Watch out for hidden sources of FODMAPs.

The following foods can be unexpected sources of FODMAPs:

    • Baked goods (wheat, high-fructose corn syrup)
    • Gluten-free flour blends (some include bean flours)
    • Granola bars (agave, honey, chicory root)
    • Marinara sauce (onion, garlic)
    • Salad dressings (onion, garlic)
    • Stock or broth (onion, garlic)
    • Supplements

3. Find creative ways to add flavor to foods.

There are many ways to add flavor to meals without high-FODMAP ingredients:

    • Add mustard to homemade marinades or salad dressings instead of garlic.
    • Cook with low-FODMAP herbs and spices.
    • Instead of onions, use small amounts of the green parts of scallions and leeks.
    • Try using nutritional yeast to replace cheese.
    • Use garlic-infused oil to add flavor in lieu of fresh garlic (FODMAPs are water-soluble, so they will not enter the infused oil. Just make sure to discard the garlic pieces before using.)

Low-FODMAP Food List (from Monash app data, November 2019)

The following foods are considered to be low-FODMAP when consumed as 1 standard serving size (unless otherwise specified). 

Please note: We recommend using the Monash app for the most up to date data and access to portion size recommendations. This is very important!!


    • Dragon fruit
    • Durian
    • Grapes (red, green, or black)
    • Guava
    • Lemons
    • Limes
    • Mandarin oranges
    • Olives (black or green)
    • Oranges
    • Papaya (yellow)
    • Plantain
    • Prickly pear
    • Pineapple
    • Rhubarb
    • Star fruit
    • Strawberries


    • Alfalfa sprouts
    • Arugula
    • Baby corn (canned)
    • Bamboo shoots
    • Bean sprouts
    • Bell peppers (red only)
    • Carrots
    • Choy sum
    • Collard greens
    • Cornichon pickles
    • Cucumber
    • Endive
    • Eggplant
    • Gai lan
    • Hearts of palm (canned)
    • Jalapeno (pickled)
    • Kale
    • Kohlrabi
    • Lettuce (butter, iceberg, red, romaine)
    • Oyster mushrooms (no other types)
    • Parsnip
    • Potatoes
    • Radish
    • Rutabaga
    • Swiss chard
    • Spaghetti squash
    • Spinach
    • Scallions (green part only)
    • Tomatillos
    • Tomatoes (¾ cup canned or 1 small raw)
    • Water chestnuts
    • Watercress
    • Yardlong beans

Grains & Starches

    • Agar agar
    • Arrowroot
    • Buckwheat flour
    • Chickpea pasta
    • Corn flour, meal, or starch (NOT corn kernels)
    • Corn tortillas (no added gums or fiber)
    • Gluten-free pasta
    • Green banana flour
    • Kelp noodles
    • Millet
    • Millet flour
    • Oats
    • Oat bran
    • Oat groats
    • Oatmeal
    • Polenta
    • Potato starch
    • Quinoa
    • Quinoa flour
    • Quinoa pasta
    • Rice (brown, white)
    • Rice bran
    • Rice flour
    • Rice noodles
    • Sorghum flour
    • Tapioca starch
    • Teff flour

Nuts & seeds

    • All except cashews, hazelnuts, and pistachios 

Dairy & Dairy Alternatives

    • Almond milk
    • Cashew milk
    • Coconut yogurt
    • Hard & ripened cheeses (gruyere, manchego, pecorino, cheddar, monterey jack, colby, swiss, etc.)
    • Hemp milk
    • Lactose-free cream cheese
    • Lactose-free milk
    • Lactose-free yogurt
    • Macadamia milk
    • Oat milk
    • Quinoa milk
    • Rice milk
    • Soy milk (if made from soybean extract, not whole soybeans)

Meat & Vegetarian Protein Sources:

    • Bacon
    • Beef
    • Chicken
    • Eggs
    • Fish
    • Kangaroo
    • Lamb
    • Pork
    • Prawns
    • Spirulina
    • Tempeh
    • Tofu

Fats & Oils

    • Animal fats
    • Avocado oil
    • Butter & ghee
    • Canola oil
    • Coconut oil
    • Olive oil (plain or garlic infused)
    • Peanut oil 
    • Mayonnaise
    • Rice bran oil
    • Sesame oil
    • Sunflower oil
    • Vegetable oil
    • Walnut oil


    • Any fresh herbs
    • Any dried herbs or spices (except for onion and garlic)
    • Allspice
    • Apple cider vinegar
    • Asafoetida powder
    • Basil
    • Black pepper
    • Capers (salted or in vinegar)
    • Cardamom
    • Chili powder
    • Chives
    • Cilantro
    • Cinnamon
    • Cloves
    • Cocoa or cacao powder
    • Coriander
    • Cumin
    • Curry leaves
    • Curry powder
    • Dill
    • Fennel seeds
    • Fenugreek (seeds or dried leaves)
    • Five-spice
    • Galangal
    • Ginger
    • Goraka
    • Gotukala
    • Herbes de Provence
    • Horseradish
    • Kaffir lime leaves
    • Lemongrass
    • Lemon juice
    • Lime juice
    • Malt vinegar
    • Mayonnaise 
    • Mint
    • Mustard (seeds or spread)
    • Nutmeg
    • Nutritional Yeast
    • Oregano
    • Oyster sauce
    • Pandan leaves
    • Paprika (plain or smoked)
    • Parsley
    • Rampa leaves
    • Red wine vinegar
    • Rice wine vinegar
    • Rosemary
    • Saffron
    • Sage
    • Shrimp paste
    • Soy sauce
    • Star anise
    • Tamari
    • Tarragon
    • Thai basil
    • Tomato paste
    • Turmeric
    • Vanilla beans
    • Vanilla extract
    • Wasabi (paste or powder)


    • Brown sugar
    • Cane sugar (white sugar)
    • Dark chocolate (70%+)
    • Maple syrup
    • Palm sugar
    • Rice malt syrup
    • Stevia


    • Beer
    • Coffee
    • Gin
    • Cranberry juice (unsweetened)
    • Tea (black, green, or white)
    • Vodka
    • Whiskey
    • Wine

Low-FODMAP products:


Broth, Stock, & Soup

Sauces & Marinades





    • Enjoy Life Chocolate (semi-sweet chips or chunks, dark chocolate morsels, dark chocolate bars, rice milk chocolate bars)



High-FODMAP Food List (from Monash app data, November 2019)

High-Fructan High-GOS High-Lactose High-Fructose High-Sorbitol High-Mannitol
Fruits Banana (ripe)
Coconut flour
Cranberries (dried)
Figs (dried)
Goji berries (dried)
Honeydew melon
Mango (dried)
Paw paw (dried)
Peaches (white)
Pineapple (dried)
Custard apple Apple
Asian pear
Coconut flour
Figs (fresh)
Guava (unripe)
Mango (fresh)
Asian pear
Coconut flour
Peaches (clingstone, white, yellow
Peaches (clingstone)
Vegetables Artichoke
Brussels sprouts
Cabbage (savoy)
Corn (canned)
Fennel bulb
Green onion (white part)
Green peas (frozen)
Leek (white part)
Lotus root (dried)
Onion (red, white)
Snow peas
Bitter melon
Butternut squash
Green peas (canned, frozen)
Snow peas
Black garlic
Broccoli stalks
Chipotle chili (dried)
Lotus root (dried)
Sugar snap peas
Corn (fresh)
Mushrooms (dried black chanterelle)
Mushrooms (white button, enoki, dried porcini, portobello, shiitake)
Snow peas
Grains Amaranth
Legumes Baked beans
Black beans
Kidney beans
Lima beans
Mung beans
Navy beans
Pinto beans
Soy beans
Split peas
Adzuki beans
Baked beans
Black beans
Borlotti beans
Butter beans
Chana dal
Chickpeas, sprouted
Kidney beans
Lima beans
Mung beans
Navy beans
Pinto beans
Soy beans
Split peas
Baked beans
Broad beans
Fava beans
Nuts and seeds Cashews
Dairy &
Dairy Alternatives
Oat milk Soy milk (from soy beans) Buttermilk
Condensed milk
Cow’s milk
Evaporated milk
Goat milk
Other Agave
Carob powder
Chai tea
Chamomile tea
Coconut water
Cream-based pasta sauce
Dandelion tea
Fennel tea
Golden syrup
Herbal tea
Oolong tea
Pasta sauce with garlic and onion
Sorghum syrup
Pasta sauce with garlic and onion Cream-based pasta sauce Agave
Apple juice
Orange juice
Apple juice
Coconut water

Frequently Asked Questions

1. Do FODMAPs cause IBS?

FODMAPs may exacerbate symptoms, but there is no evidence that FODMAPs cause IBS (63).

2. Why are garlic- and onion-infused oils allowed?

FODMAPs are not fat-soluble, so they won’t end up in the oil after the onion and garlic are removed (64).

3. Is this diet safe for vegetarians and vegans?

Yes, but it is recommended that patients work with a dietitian to ensure adequate protein intake.

Low-FODMAP protein sources for vegans:

    • Certain soy products (tempeh, firm tofu) – fodmaps are water-soluble, so most are pressed out when tofu blocks are made. They are also fermentable, so most of the fodmaps are fermented and broken down when tempeh is made.
    • Milk substitutes (protein-enriched rice milk, quinoa milk, hemp milk, macadamia nut milk, almond milk, or soy milk made with soy protein)
    • Nutritional yeast
    • Nuts and seeds (except pistachios and cashews)
    • Seitan (vital wheat gluten)
    • Spirulina
    • Whole grains (buckwheat, millet, quinoa, wild rice)

Low-FODMAP protein sources for vegetarians include all of the foods mentioned above, plus the following:

    • Eggs
    • Hard cheeses (cheddar, parmesan, swiss)
    • Lactose-free milk
    • Lactose-free yogurt

4. What is a “FODMAP-gentle” diet?

If a strict low-FODMAP diet is not feasible, a “FODMAP-gentle” diet, which restricts only a few of the foods highest in FODMAPs, might be prescribed (49).

5. Is it okay to continue to take probiotics during the elimination and challenge phases?

If someone is already taking a probiotic, they should continue to take it during the elimination and challenge phases. 

However, if someone is not currently taking probiotics, they should not start them at this time. The goal is to manipulate one variable at a time. 

Recommended resources:




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