Do you often experience digestive stress after eating certain foods?

Can the discomfort be so severe that it affects your day-to-day activities?

The link between foods and digestive disorders is well recognised, and there is a good chance that FODMAPs – small carbohydrates in certain foods – are the culprit.

As a food intolerance dietitian, I’ve seen how remarkable a low-FODMAP diet can be for people with chronic gastrointestinal symptoms… 

Things like recurrent bloating, gas, cramps, diarrhea or constipation. This diet is one of the natural ways known to alleviate such chronic symptoms.

If you’re keen to learn more, and maybe even try a low FODMAP diet for yourself, this 2,000 word beginner’s guide is a great place to start.

A low FODMAP diet is also known as a FODMAP elimination diet.

This is a temporary eating pattern that has a very low amount of food compounds called FODMAPs.

The acronym stands for:

● Fermentable - meaning they are broken down (fermented) by bacteria in the large bowel

● Oligosaccharides - “oligo” means “few” and “saccharide” means sugar. These molecules are made up of individual sugars joined together in a chain

● Disaccharides – “di” means two. This is a double sugar molecule

● Monosaccharides – “mono” means single. This is a single sugar molecule

● And Polyols – these are sugar alcohols (however, they don’t lead to intoxication!)

As you can see, there are four main saccharide groups that make up FODMAPs – oligosaccharides, disaccharides, monosaccharides and polyols.

These FODMAP groups have specific names and may also have more than one group within them, known as a FODMAP subgroup:

● Oligosaccharides have two subgroups, known as fructans and galactans (or galacto-oligosaccharides or GOS for short)

● Disaccharides are known as lactose and only contain one group

● Monosaccharides are known as fructose (or excess fructose) and also only contain one group

● Polyols have two subgroups, known as sorbitol and mannitol

Let’s stick with the term FODMAPs shall we?

Those saccharides and polyols are short-chain carbohydrates that, if poorly digested, ferment in the lower part of your large intestine (bowel).

This fermentation process draws in water and produces carbon dioxide, hydrogen, and/or methane gas that causes the intestine to stretch and expand.

The result is strong pain, bloating, visible abdominal distension and other related symptoms (1).

1. Food is eaten that contains FODMAPs.

2. Some FODMAPs may pull water into the small intestine, causing diarrhea

3. In those with IBS, FODMAPs can travel to the large intestine (gut) largely undigested.

4. When “unhealthy” bacteria interact with FODMAPs in the gut, it causes a range of symptoms such as bloating, gas and pain.

5. Different people are sensitive to different FODMAPs, so it’s important to identify which ones are the culprit.

This is a wonderful short video by Australian researchers that illustrates what FODMAPs are and how they impact our digestion:

The primary use of this diet is to relieve digestion-related symptoms, but is emerging as a useful treatment tool for several other conditions too.

It can be useful for those with:

● Irritable Bowel Syndrome (IBS)- more on that below

● Other forms of Functional Gastrointestinal Disorder (FGID)

● Small intestinal bacterial overgrowth (SIBO)

● Certain auto-immune conditions/diseases like (potentially) rheumatoid arthritis, multiple sclerosis or eczema

● Fibromyalgia or other health issues you’ve noticed are triggered by certain foods

● Frequent migraines that appear to be triggered after certain meals

● Inflammatory bowel disease (IBD) such as Crohn’s disease, ulcerative and microscopic colitis.

The best candidates for trialling this diet also tend to answer yes to these questions.

And note that it’s not to be confused with a food chemical intolerance such as a low Histamine Diet or a low Salicylate diet.

Tap the blue button below to download our complete FODMAP “Eat This, Not That” food list (it’s free!)

This is a giant list of what foods to eat, and what foods to avoid when following a low FODMAP diet.

It’s based on the latest published FODMAPs data and looks like this:

Also note that like with anything food related, portion size is fundamental. A serving of 10 almonds are considered low FODMAP, but if you eat 20 almonds then you will end up eating a high amount of FODMAPs.

As with anything we eat, the dose makes the poison.

Common FODMAPs in your food include:

● Fructose: A sugar found in most fruits and vegetables.

● Lactose: A sugar found in dairy foods like milk.

● Fructans: A chain of sugars found in many vegetables and grains.

● Galactans: Found primarily in legumes.

● Polyols: Sugar alcohols like sorbitol and mannitol. You find them mainly in artificial sweeteners and chewing gum but they are also naturally occurring in various fruits and vegetables.

The Monash University low FODMAP diet phone app is a great place to start when reading food labels.

You can check the app for foods that have been tested as high FODMAP.

It’s also useful to know other common high FODMAP ingredients such as inulin (chicory root), natural flavors, high fructose corn syrup, agave, honey, etc so you can avoid them also.

Much of the research has been on patients with Irritable Bowel Syndrome (IBS).

IBS is a chronic gastrointestinal disorder characterised by abdominal pain and altered bowel habits, and around two thirds of IBS patients report their symptoms are related to food.

It’s now estimated to affect 11% of the population globally, up to 13% in Australia and up to a whopping 20% in the US and UK (2, 3).

One landmark clinical trial compared the responses of 39 IBS patients who received standard healthy eating advice against 43 IBS patients who received low FODMAP training from a dietitian (13).

IBS symptoms were reduced by 50% overall on the low FODMAP diet, with the greatest improvements observed one week after implementing the diet. More specifically, improvements were seen for bloating, abdominal pain, wind and dissatisfaction with stool consistency.

Numerous similar studies (albeit not as well designed) have found very similar benefits, and the overall average success rate is about 68-76% of patients (5, 6).

Research in this area still has a way to go, but scientific consensus is that a low FODMAP diet should be the first dietary approach for treatment of recurrent gastrointestinal issues.

Set meal plans aren’t particularly useful when you’re eating out at a restaurant or takeaway shop. Here are some food choice tips to help you make appropriate choices:

● Café: choose tea or coffee with lactose-free or almond milk, poached eggs on sourdough or gluten free bread with grilled low FODMAP vegetables, lactose-free yoghurt with low FODMAP fruit (Greek yogurt or quark is okay too but still has some lactose), smoothies made with lactose-free or almond milk and low FODMAP fruits and vegetables
● Pub food: choose plain meat, chicken and fish with low FODMAP salad or vegetables, olive oil and lemon juice as a dressing, fries with plain salt

● Asian: choose stir fries with no onion or garlic, sushi, sashimi or rice paper rolls

● Mexican: ask for no onion, garlic, beans and sour cream on corn nachos or tacos

● Italian: choose gluten free pasta and ask for an accompanying sauce that does not contain onion or garlic, or ask for a salad with plain meat or chicken with olive oil and lemon juice as a dressing

● Fast food: choose fries with plain salt

● Cinemas: choose popcorn and water

As you can see the low FODMAP diet is complex.

This is generalised advice and may be difficult to do yourself without professional guidance.

Group education sessions have recently been used with success, but it’s traditionally done in a one-on-one setting so that any diet modifications are individualized. In fact, the diet has only ever been evaluated formally as a dietitian-delivered diet (12).

For this reason it’s recommended to do this under the guidance of a dietitian where possible.

That said, with the quality of resources now available online it certainly can be done on your own, but you must be highly motivated and disciplined.

I recommend you to buy the Monash University Low FODMAPs app. Monash is the world’s leading source of FODMAP research and information (from Melbourne, Australia), and their app is worth every penny.

Consider probiotics as well either before you start the FODMAP diet or after you have finished. Also speak with your doctor or dietitian first just in case you require medication.

Safely removing and reintroducing the appropriate foods takes a lot of learning upfront, but countless patients can tell you it’s worth it.

Whey protein isolate (WPI) is low FODMAP at 40 grams. Whey protein concentrate (WPC) may not always be low FODMAP depending of the lactose content.

Rice and pea protein are vegan protein powders that are low FODMAP at 40 grams (2 tablespoons).

Just also check that the protein powder doesn’t contain any other high FODMAP ingredients.

For more detailed information on picking a low FODMAP protein powder see this article.

Can I still do The Low FODMAP Diet if I’m a Vegetarian or Vegan?

Yes of course, but it can be more tricky because many staple vegetarian and vegan protein options are high FODMAP.

This includes legumes, some nuts and soy products.

Low FODMAP vegetarian and vegan protein options include:

● Firm tofu (2/3 cup cubed, 160g)
● Tempeh (100g)

● Quorn mince, no onion (75g)

● Eggs (2 eggs, 117g)

● Some nuts and seeds (refer to this low FODMAP food list for specifics)

● Canned and rinsed chickpeas/garbanzo beans and butter beans (1/4 cup, 42g)

● Canned and rinsed lentils (1/2 cup, 46g)

● Quinoa (1 cup cooked, 155g)

● Soy protein milk (1 cup, 250ml)

● Lactose free cow’s milk (1 cup, 250ml)

● Lactose free yogurt (1 tub, 170g)

● Greek yogurt (4/5 cup, 200g)

● Hard yellow cheese e.g. cheddar, Colby, Swiss (2 slices, 40g)

● Cottage cheese (4 tablespoons, 36g)

● Soy cheese (2 slices, 40g)

Yes and no. Let’s start with the no.

Unfortunately, most FODMAPs mix with water (known as water soluble). This means mixing high FODMAP foods with other ingredients when cooking could see the FODMAPs leach into the low FODMAP food (virtually every other ingredient or food contains water). Cooking with garlic and onion is the main example when this occurs.

It’s thought that high temperature cooking can breakdown FODMAPs (potentially favorable), but to what extent is not yet known. Therefore, currently the best way to keep your meal low FODMAP is to cook with only safe ingredients.

Cooking with garlic and/or onion in oil is safe as long as you remove all pieces before you add any other ingredients. While FODMAPs mix with water, they do not mix with oil (much like water does not mix with oil, if you ever drop oil into water you will see).

So for example, you can cook whole garlic cloves in oil, which allows the flavor compounds to mix with the oil but not the FODMAPS. Then remove the garlic from the oil before adding any other ingredients (so keep the garlic pieces large so they are easy to remove). This leaves you with what is essentially garlic-infused oil, which is low FODMAP.