Digestive health since 2008Learn More About FODMAPs
FODMAPs
Learn More About FODMAPs
FODMAPs are short-chain carbohydrates that may be poorly absorbed or digested. Water movement and bacterial fermentation can contribute to bloating, wind, discomfort or altered bowel habits in people with a sensitive gut. They are ordinary food components, not inherently harmful substances.
FODMAPs stands for:
- Fermentable
- Oligosaccharides (such as fructans and GOS)
- Disaccharides (lactose)
- Monosaccharides (such as fructose)
- Polyols (such as sorbitol, mannitol and xylitol)
What are FODMAPs?
FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. The amount eaten, the type of carbohydrate and the person’s bowel sensitivity all influence symptoms. A low-FODMAP approach is a structured dietary trial for suitable people with medically diagnosed IBS, rather than a general healthy-eating rule.
Oligosaccharides
The relevant oligosaccharides include fructans and galacto-oligosaccharides. These short carbohydrate chains are found in plant foods and are often referred to as fructans and GOS. These compounds occur naturally in a variety of vegetables, fruits, grains, legumes, and nuts..
Disaccharides
A disaccharide contains two sugar units. Lactose is the disaccharide assessed within the FODMAP framework. Lactose is primarily found in milk, other dairy products, and various processed foods.
Sucrose is also a two-unit sugar, but it is not classified as a FODMAP. Suspected sucrose digestion problems need separate consideration rather than being treated as part of every low-FODMAP diet.
Monosaccharides
A monosaccharide is a single sugar molecule. In FODMAP assessment, attention is given to excess fructose, particularly where a food contains more fructose than glucose. It is present naturally in foods and can also be used in sweetening ingredients.
Polyols
Polyols are sugar alcohols. Examples relevant to food tolerance include sorbitol, mannitol, and xylitol. They occur naturally in some produce and can also be added to sugar-free confectionery, chewing gum and other foods.
What Products Contain FODMAPs?
The following examples illustrate food sources, not a universal avoid list. FODMAP content changes with portion size, processing and sometimes ripeness. Consult current Monash serving guidance when planning a dietary trial.
Oligosaccharides (fructans and GOS)
Fructans are found in:
- Onions, garlic, leeks, shallots
- Wheat, rye and barley (and products made from these grains, such as bread, pasta and breakfast cereals)
- Vegetables such as artichokes, asparagus and certain types of cabbage, such as white cabbage and Brussels sprouts
GOS (galacto-oligosaccharides) are found in:
- Legumes such as beans, lentils and chickpeas
- Soybeans and soy-based products (such as tofu and soy milk)
- Vegetables such as beetroot, cassava and onions
Disaccharides (lactose and sucrose)
Lactose is found in:
- Milk (cow’s milk, goat’s milk, sheep’s milk)
- Dairy products such as yoghurt, ice cream, cheese (especially fresher cheeses such as ricotta and mozzarella)
Sucrose is found in:
- Sweets such as confectionery, biscuits, cakes and pies
- Drinks such as soft drinks, fruit juices with added sugar and energy drinks
- Sauces and dressings such as ketchup, barbecue sauce and some salad dressings
- Processed foods such as breakfast cereals, granola bars and cereals with added sugar
Monosaccharides (fructose) is found in:
- Fruit such as apples, pears, watermelon, mangoes, grapes
- Honey and agave syrup
- Fruit juices and sweeteners such as high-fructose corn syrup (HFCS)
Polyols (sorbitol, mannitol, xylitol, and others) is found in:
- Sweeteners in sugar-free chewing gum, sweets and chewable tablets
- Vegetables such as mushrooms, cauliflower and capsicum
- Fruits such as plums, peaches, apples and cherries
For a clear overview see the document: “List of FODMAPs in food”. You can download it for free from the Educational materials.
How are FODMAPs Digested?
FODMAPs follow different pathways. Some need enzymes before absorption, some are absorbed directly, and some pass to the large bowel for fermentation:
Oligosaccharides (such as fructans and galactans)
Humans do not produce the enzymes required to fully digest fructans and GOS in the small intestine. Bacteria in the large bowel use these carbohydrates instead. For more detail and practical food examples, see the guide about fructans and galactans.
Disaccharides (such as lactose and sucrose)
Lactose needs lactase to split it into absorbable sugars. Sucrose is broken down by sucrase, although sucrose itself is not a FODMAP. Reduced activity can allow more of the relevant sugar to reach the large bowel. Explore the page about lactose and more about the digestion of sucrose on the page about starch and sucrose.
Monosaccharides (such as fructose)
Fructose is already a single sugar and does not need to be split before absorption. If the amount exceeds the intestine’s capacity to absorb it, some remains available for fermentation. See the guide about fructose.
Polyols (such as sorbitol, mannitol and xylitol)
Polyols can be incompletely absorbed. The amount reaching the large bowel varies with the food and portion, and may contribute to symptoms in susceptible people.
Oligosaccharides, including fructans and GOS, are fermented by large-bowel bacteria rather than fully digested in the small intestine.
Disaccharides, such as lactose and sucrose, require enzymes to be broken down and absorbed.
Monosaccharides, such as fructose, are absorbed directly into the bloodstream without enzymatic breakdown.
Polyols are also not absorbed in the small intestine and undergo fermentation in the large intestine.
What All FODMAPs Have in Common
Fermentation happens primarily in the large bowel. It is a normal process and produces useful compounds as well as gas. FODMAPs can also influence water in the intestine; these effects may be uncomfortable for someone with IBS.
Dietary Guidelines for a Low-FODMAP Diet
Before making broad restrictions, review the person’s diagnosis, meal pattern, fibre intake, caffeine, alcohol and other relevant factors. In Australia, an Accredited Practising Dietitian can help select a manageable approach and protect nutritional adequacy. The resource buttons retain access to the step-by-step education materials.
This approach is based on the “Gut Support Pyramid”, an educational framework for reviewing digestive health in a practical sequence.
The “Gut Support Pyramid” consists of three levels. Base layer: improving the base through a balanced diet and healthy lifestyle. Support layer: avoiding foods that can serve as triggers, supplementing fibre and trying probiotics. Specific support layer: avoiding specific nutrients, testing and using supplements to further support the diet. A dietitian may suggest either a targeted reduction or a full structured FODMAP trial. The decision should reflect symptoms, usual diet and the person’s capacity to carry out reintroduction. FODMAP-light diet A gentler approach targets the foods or groups contributing most to the individual’s intake. It can reduce the burden of restriction, but still needs a clear review point and a plan to assess tolerance. 1. Approach: Reducing or Eliminating One FODMAP Group at a Time Where there is a clear reason to assess one group, a clinician may suggest a focused trial, such as reviewing lactose portions. Keep the other main variables steady and record the response. Where appropriate, discuss lactase supplements tas a separate management option. A response to lactase is not diagnostic, and enzyme products do not cover every FODMAP group. The aim is to establish a practical, varied diet rather than indefinitely avoiding all possible triggers.
2. Approach: Reducing Multiple FODMAP Groups Mixed meals can make it difficult to identify a pattern. A structured food and symptom record may help the dietitian choose what to trial first. Examples to discuss include:
- Fruit: Avoid or limit high-fructose fruits such as apples and pears.
- Dairy: Choose lactose-free alternatives or consume smaller portions.
- Legumes: Limit intake or opt for varieties with lower FODMAP content.
- Wheat: Use alternatives such as spelt or quinoa. Digestive enzymes such as
A multi-enzyme supplement is not a diagnostic test for a particular FODMAP intolerance. Check its intended substrates and Australian directions before considering it. The Low-FODMAP Diet The low-FODMAP diet has three stages: a short reduction phase, systematic reintroduction and personalisation. It is best undertaken with a dietitian experienced in IBS. 1. The Elimination Phase In the elimination phase, high-FODMAP choices are temporarily swapped for suitable alternatives, usually for 2–6 weeks under professional guidance. Review the response before continuing; a strict restriction is not the long-term goal.
2. The Reintroduction Phase In the reintroduction phase, individual FODMAP groups are challenged in a planned way while symptoms are recorded. Portion size is increased according to the agreed protocol.
3. The Personalization Phase During the personalization phase, the results are used to bring back as much variety as possible. Keep only restrictions that are helpful, reassess tolerance over time and review fibre, calcium and other nutritional needs.