If you have a FODMAP intolerance, it means your digestive system is unable to tolerate (digest and absorb) certain (or many/all) types of high FODMAP foods.
Read on to learn how you can better understand, navigate, and effectively manage FODMAP intolerances at a deeper level, from a holistic gut health nutrition standpoint.
Disclaimer: This post was written for educational purposes, to complement and enhance but not replace medical and dietary advice from your doctors and a gut health dietitian. Make sure to consult with your treatment team for custom advice tailored to your bio-individual needs.
Table of Contents
First things first: What does FODMAP stand for?
“FODMAP” is an acronym which stands for “fermentable oligosaccharides, Disaccharides, monosaccharides, and polyols.”
What are FODMAPs?
FODMAPs are different types of small-sized, difficult-to-digest carbohydrates which have the highest chances of getting fermented (consumed) by microbes in our small intestine (part of the lower digestive tract).
Note that FODMAPs aren’t inherently bad.
In fact, being fermentable, FODMAPs are actually prebiotic which means they help feed good bacteria in cases where your gut is healthy.
But if you’re experiencing any kind of food intolerance to FODMAPs, it’s a sign something in your digestive system is out of alignment.
What’s a food intolerance?
A food intolerance is a sub-type of adverse reaction to foods which is caused by an underlying digestive insufficiency and/or microbial overgrowth in your gut.
Food intolerance symptoms may include any or all of the following, usually within 1 to 2 hours or immediately following consumption of a reactive food:
- Gas
- Bloating
- Abdominal pain/cramping
- Diarrhea
- Constipation
- Nausea/vomiting
Food intolerance vs. sensitivity
It’s also important to note that food intolerances happen exclusively in the gut.
So if you’re experiencing other types of adverse food reactions and symptoms like migraines, joint pain, skin breakouts, or hives, you may want to consider reading about the key similarities and differences between food intolerances, food sensitivities, and food allergies.
Recommended reading: Food Allergy vs. Intolerance vs. Sensitivity: How to Tell Them Apart
What’s a FODMAP intolerance?
While many folks can eat high FODMAP foods without any kind of negative consequences and unwanted symptoms, not everyone is so fortunate!
A FODMAP intolerance is a type of food intolerance in which you get uncomfortable digestive symptoms within an hour or two after eating any reactive foods high in FODMAPs.
Signs and symptoms
If you’re among the millions worldwide with a FODMAP intolerance, it means you can’t eat certain types of high FODMAP foods without unwanted gastrointestinal (GI) symptoms.
The most common signs and symptoms of a FODMAP intolerance include:
- Gas (burping/flatulence)
- Bloating/distention
- Abdominal pain/cramping
- Diarrhea and/or constipation
- Nausea/vomiting
Note that FODMAP intolerances can vary from one person to another and they exist on a spectrum.
In other words, not everyone will experience all of the above symptoms after consuming foods high in FODMAPs…
And you may not react to all types of high FODMAP foods but rather certain types or categories of FODMAPs.
What causes FODMAP intolerance: breaking it down (pun intended)
If you’re intolerant to high FODMAP foods, it means something in your gut is out of balance.
More specifically, FODMAP intolerances are caused by an underlying digestive insufficiency and/or microbial overgrowth.
A digestive insufficiency is responsible for undigested or poorly digested food particles which make their way into your small intestine and/or colon.
The most common examples of digestive insufficiency in cases of FODMAP intolerance include:
- Missing or insufficient digestive enzyme production
- Excess or deficient stomach acid levels
Microbial overgrowth is responsible for the fermentation of the undigested food particles, which leads to gas production. The gasses from fermentation are responsible for symptoms such as gas, bloating, abdominal distention, and sometimes constipation and/or diarrhea.
“Microbial overgrowth” in cases of FODMAP intolerance could be any or even all of the following in your small intestine and/or colon:
- Pathogenic infections
- Parasites
- Dysbiosis
- Fungal overgrowth
- Small intestinal bacterial overgrowth (SIBO)
Undigested FODMAPs in your colon (large intestine)
Diarrhea, gas, bloating, and abdominal pain/cramping can also happen by osmosis.
In other words, when the undigested or poorly digested FODMAPs pass through your small intestine into your colon, it causes water to get pulled into your colon to help dilute these too-large molecules.
The excessive amounts of water in your colon in these cases may cause pretty instant, severe symptoms of abdominal pain/cramping, bloating and usually diarrhea.
Types of FODMAPs and FODMAP intolerances
Note that the majority of the FODMAP categories end in “–saccharides”.
“–saccharide” is just a fancy biochemical name for a type of carbohydrate.
Oligosaccharides
Oligosaccharides are a category of short-chain carbohydrates which are made up of chains of 2 to 10 monosaccharides (single-unit carbohydrates such as fructose, glucose, and/or galactose) linked together via a special type of bond called “glycosidic linkages.” (1)
Oligosaccharides don’t break down easily – in fact, they pass through the small intestine still intact. (2)
While this isn’t inherently bad – in fact, oligosaccharides usually have a beneficial prebiotic effect in folks with a healthy gut microbiome (2, 3), people with irritable bowel syndrome (IBS) and/or SIBO may instead experience an oligosaccharide intolerance.
But it isn’t that simple!
According to Monash University (the leading authority on all things FODMAPs), there are two types of fermentable oligosaccharides: fructans and galacto-oligosaccharides (GOS).
You may react to one, both, or neither of the following types of oligosaccharides.
Fructans
Fructans are short chains of fructose, with a glucose molecule on the end.
“Fructo-oligosaccharides” (FOS) are a type of fructan 2 to 9 units long, while longer chains of fructans are referred to as “inulin”.
Either way, if you’re prone to a fructan intolerance, you may notice you specifically react to most or all of the following foods listed below.
Foods high in fructans
Some of the most common types of high FODMAP foods high in fructans include, but aren’t limited to:
- Garlic
- Onions
- Wheat
- Rye
- Artichokes
- Asparagus
- Beet root
- Brussel sprouts
- Cranberries
- Ripe bananas
- Figs
- Goji berries
- Grapefruit
- Watermelon
- Large quantities of cabbage
On the other hand, some people may find they can eat foods high in fructans, while galacto-oligosaccharides (GOS) send them running for the nearest bathroom.
Galacto-oligosaccharides (GOS)
On a molecular level, galacto-oligosaccharides (GOS) are short chains of galactose (a monosaccharide), with one glucose molecule on the end. (3)
Foods highest in GOS
From a nutrition standpoint, beans and peas tend to be highest in GOS followed by (4):
- Beet root
- Some nuts/seeds
- Large quantities of lentils
But this doesn’t mean you will react to them, and even if you do, it doesn’t mean you can’t ever eat beans again!
Feel free to learn more about how to enjoy beans on a low FODMAP diet here.
Now, let’s talk about disaccharides (the “D” in FODMAP).
Fermentable Disaccharides
Disaccharides are simple sugar molecules which are made up of 2 single “monosaccharides” (i.e. fructose, glucose, and/or galactose) conjoined together.
However, the only easily FERMENTABLE type of disaccharide when it comes to FODMAPs specifically is lactose (milk sugar) which consists of a glucose molecule and a galactose molecule joined together.
Lactose intolerance
Many people (with or without IBS/SIBO) are missing a key enzyme called “lactase” which is supposed to be made and released in the intestines, to help break lactose down into single units of glucose + galactose (so they may pass through the gut lining, into the bloodstream).
If you’re lactose intolerant, you’ll experience symptoms of fermentation and osmosis (gas, bloating, cramping and diarrhea) within 1 hour after consuming any food high in lactose.
Foods highest in lactose
Contrary to popular belief, not all dairy contains lactose in large quantities or even at all in many cases!
Milk is the highest food source of lactose (containing a whopping 12 grams of lactose per serving), followed by yogurt and then some types of soft cheeses.
However, note that there are low FODMAP (lactose-free) variations of all dairy available on the market which means you may not necessarily need to go dairy-free on a low FODMAP diet!
Feel free to check out the following resources to learn and understand more about how to navigate lactose and other FODMAPs in dairy:
- Low FODMAP Milk and Milk Alternatives: List and Comprehensive Guide
- Best Low FODMAP Yogurts for IBS – Comprehensive Brand/Product List & Guide
- High and Low FODMAP Cheeses: List and Guidance
- Butter is Low FODMAP – But Is It IBS-Friendly? (What Else to Consider)
- Is Ghee Low FODMAP? What Else You Need to Know about Ghee and IBS
Lactose intolerance vs. casein intolerance vs. dairy sensitivity
Note that if you’re reacting to low FODMAP dairy like hard cheese, lactose-free milk/yogurt, but not butter and/or ghee, you could potentially be dealing with a casein intolerance.
If you find that butter and/or ghee also bother you, you may want to look into the possibility of a fat intolerance and/or dairy sensitivity.
Learn more: Lactose Intolerance vs. Dairy Sensitivity: How to Tell Them Apart
Fermentable monosaccharides
As I mentioned earlier, monosaccharides are single-unit carbohydrates – specifically glucose, fructose, and galactose.
However, the only type of fermentable monosaccharide is FRUCTOSE.
Much like lactose intolerance, many people presenting with IBS symptoms are walking around with an underlying fructose intolerance which could be caused by a digestive enzyme deficiency and/or a microbial overgrowth in your small intestine.
Fructose intolerance
Eating foods high in fructose can trigger IBS symptoms (diarrhea, abdominal pain/cramping, gas, bloating, nausea) if you have a fructose intolerance.
Foods high in fructose
Some of the foods highest in fructose to consider when ruling out a fructose intolerance include (but aren’t limited to) (4):
- Agave nectar
- Apples
- Artichokes
- Cherries
- High fructose corn syrup
- Honey
- Coconut sugar
- Molasses
- Dates
- Grapes
- Pears
- Watermelon
- Large quantities of tomatoes or peppers
Polyols
Polyols are the “P” in FODMAP. They represent an entire category of sugar alcohols (think: sorbitol, xylitol, etc.) which are not easily broken down in the intestines.
While polyols (like other FODMAPs) can be prebiotic and beneficial for some people, they’re very common IBS symptom triggers among many of my clients.
Some little-known culprits high in polyols (such as sorbitol/mannitol) include but aren’t limited to (4):
- Apples
- Apricots
- Avocado
- Blackberries
- White cauliflower
- Celery
- Mushrooms
- Nectarines
- Peaches
- Pears
- Plums
- Watermelon
Recommended reading:
- What are Polyols? Exploring the “P” in FODMAP
- Is Erythritol Low FODMAP? (The Low-Down on Erythritol and IBS)
- Is Avocado Low FODMAP? (How to Navigate the FODMAPs in Avocados)
- When is Cauliflower Low FODMAP? (A Little-Known Way to Try Low FODMAP Cauliflower)
Who’s most likely to experience FODMAP intolerances?
In my experience running a gut health nutrition clinic since 2014, people with irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO) are MOST likely to have a FODMAP intolerance.
These two conditions are very similar on the surface level, so they get confused a lot.
IBS
IBS (irritable bowel syndrome) is a functional gut disorder that you get diagnosed with, when doctors have ruled out medical conditions such as SIBO (below), inflammatory bowel disease (IBD), and/or celiac disease.
In my experience as a gut health dietitian and former IBS sufferer, IBS is most commonly the culmination of a fusion of functional microbial imbalance (dysbiosis), microbial overgrowth, a compromised gut barrier (aka “leaky gut”) and/or a mis-wired nervous system.
- Read more about the different types of IBS (and how to navigate it) here!
SIBO
Small intestinal bacterial overgrowth or “SIBO” is quite literally a condition in which microbes are over-growing in your small intestine (where they don’t belong) – so they’re fermenting a lot of the foods you’re eating, leading to excessive gas production.
The signs and symptoms of the different types of SIBO overlap a lot with IBS, and testing for SIBO isn’t 100% accurate so it can take a while to get properly diagnosed and treated for this.
- Read more about the different types of SIBO and how to navigate it here!
Acquired sucrase-isomaltase deficiency
If you’re among the growing number of people with a sucrase-isomaltase enzyme deficiency (especially the acquired type which is often the result of SIBO left unchecked), you may be more prone to developing FODMAP intolerances – especially to lactose, garlic, onions and other low sucrose, high FODMAP foods.
(This is my professional speculation, based on what I’ve been seeing in my private practice lately!)
How to know if you have a FODMAP intolerance?
As I mentioned earlier, FODMAP intolerances exist on a spectrum and may vary from one person to another in terms of reactive foods and symptoms.
But testing and observing can go a long way.
Below is a brief summary of how I help my clients identify FODMAP intolerances in my gut health nutrition practice.
FODMAP intolerance test: Is there such a thing?
Technically you can test for certain types of FODMAP intolerances, specifically the monosaccharides (like fructose) and disaccharides (lactose).
This is via a fructose breath test or a lactose breath test, respectively.
But these tests don’t account for OTHER types of FODMAP intolerances such as oligosaccharides and polyols.
That’s where elimination and reintroduction diets (alongside a food-symptom journal and clinical guidance/supervision from a FODMAP-trained dietitian) can go a long way!
Low FODMAP elimination diet
Working with a registered dietitian who can help guide you through a customized low FODMAP diet can go a long way!
- Read more about the low FODMAP elimination and reintroduction diet here.
(But note that in most cases, research is showing it isn’t beneficial to STAY on a low FODMAP/low prebiotic diet long-term for symptom management. The idea is you want to identify and address the root causes of your FODMAP intolerances!)
Food-symptom journaling
Keeping a food-symptom journal can also go a long way to help you connect the dots and look for patterns when it comes to food-symptom triggers and FODMAP categories.
- Check out my 5 best-practice tips for keeping an IBS food diary here.
What can you do about it?
Low FODMAP elimination and reintroduction
If a low FODMAP diet works well for you, it may be worth leaning more into low FODMAP meal ideas and recipes!
Monash University recommends a complete low FODMAP diet for up to 8 weeks before testing, challenging, and reintroducing some high FODMAP foods.
If you’d like some extra creativity and inspiration on a low FODMAP diet for IBS symptom management (while enjoying tasty food and nourishing meals), consider checking out and ordering your own copy of my holistic 7-day low FODMAP meal plan & eCookbook!
Enzyme replacement
Aside from going on a low FODMAP diet (which as I mentioned earlier, can be helpful short-term but not necessarily healthy or recommended long-term/indefinitely), you can also consider trying out digestive enzymes to help break down the FODMAPs in foods.
Some of my favorite digestive enzymes for breaking down FODMAPs in foods include Lactaid (for lactose), Fructaid, Beano (for GOS), FODZYME* and FODMATE.
- Enter my affiliate code WHOLEISTICLIVING for 15% off your first FODZYME order here*! (As a FODZYME affiliate, I may earn a commission on qualifying purchases at no extra cost to you.)
Root-cause approach
Getting to the root cause of your FODMAP intolerances is not easy, but it’s worth a shot in my opinion.
Working through a 5R protocol is how some of my clients have been able to break free from some or most of their FODMAP intolerances over time.
Consult a FODMAP-trained dietitian
Recap
FODMAP intolerances exist on a spectrum; to have a FODMAP intolerance means you’re having adverse reactions (diarrhea/constipation, gas/bloating, abdominal pain, and/or nausea/vomiting) within a few hours after eating certain types of high FODMAP foods.
These types of food intolerances mean something in your gut is out of alignment, usually in the realm of digestive insufficiency, gut inflammation, and/or microbial imbalance.
To identify your FODMAP intolerances, consider keeping a detailed food-symptom journal, and working with a FODMAP-trained gut health dietitian 1-1 for guidance and support around possibly trying out a customized elimination and reintroduction diet.
For symptom management, the best options are to reduce/avoid reactive foods and/or to lean on enzyme replacement if it’s helpful.
If you’d like to address the root causes of your FODMAP intolerances, consider working specifically with a functional registered dietitian who can help you pinpoint underlying gut imbalances.
How to manage and navigate FODMAP intolerances holistically
Okay, so you’ve figured out you’ve got FODMAP intolerances… now what?
Your journey doesn’t stop here!
The next step (aside from identifying and removing the specific high FODMAP foods triggering your symptoms) is to figure out WTF is causing your FODMAP intolerance(s) in the first place.
Cause remember, that ish* ain’t normal! (It means something in your gut is OFF.)
Next steps
If you’d like to learn more about how to navigate a FODMAP intolerance holistically, here are some tools, tips and resources to get you started:
- Download my Low FODMAP Foods List PDF (free download)
- Order your 7-day holistic low FODMAP meal plan and eCookbook
- Apply to work with me 1-1 client (join the waitlist)
Wishing you all the best on your journey no matter which path you take!
XX – Jenna
