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Updated: Jul 10, 2023

Have you ever experienced bloating, abdominal cramping, pain or distention? Do you consider yourself sensitive or intolerant to certain foods? Do you avoid eating foods that you know are healthy, simply because they cause abdominal symptoms that aren't worth the discomfort?

You could be suffering from IBS, or irritable bowel syndrome, and some of the foods you're avoiding may be the solution, not the problem.

Although IBS doesn't affect life expectancy, surveys have shown that people affected by the condition would give up 25% of their remaining lives in exchange for a permanent cure. This is proof that this condition is relentless and reeks havoc on people's quality of life.

IBS is a disorder of the GI tract characterized by chronic abdominal pain and altered bowel habits. In North America, approximately 10-15% of people fit the criteria for the diagnosis, although we know that up to half of the people with compatible gastrointestinal symptoms will remained undiagnosed. People affected by this disorder will often self-treat, meaning that they'll purposely avoid certain triggers or describe themselves as being intolerant or allergic to certain foods, not realizing that the avoidance of some of these foods might actually be contributing to their symptoms or making them worst. I'll explain this counter-intuitive statement later!


Diagnosing IBS is made by excluding other bowel diseases first. If you think you might have IBS, you should absolutely see you doctor to rule out other bowel conditions. Once other bowel diseases causing structural damage and other biochemical abnormalities have been ruled out, a diagnosis can be made if you meet certain criteria. The ROME IV criteria are widely accepted as being a reasonable way of diagnosing IBS. According to the Rome IV criteria, IBS is defined as recurrent abdominal pain, on average, at least one day per week in the last three months, associated with two or more of the following criteria, where symptoms are:

• related to defecation

• associated with a change in stool frequency

• associated with a change in stool form (appearance)

Other criteria, such as the Manning criteria, include relief of pain with bowel movements, looser and more frequent stools with onset of pain, passage of mucus, and a sense of incomplete emptying as additional symptoms, although there has been conflicting data regarding the predictive ability of the Manning criteria. IBS can then further be characterized by the predominant symptoms, like constipation-predominant IBS, diarrhea predominant IBS, mixed bowel habits IBS or unclassified IBS.


IBS is a complex disorder, where many moving parts are interlinked and contribute to the overall symptomatology. Normal bowel function requires a healthy gut microbiome (aka a healthy quantity and variety of gut bugs), an intact gut mucosa (aka gut lining) that isn't too permeable (or "leaky"), and an intact gut-brain axis. It's important to understand how these 4 different concepts affect gut health so we can then understand how to manage them. In summary, IBS can be caused by different, yet related factors, like:

  • dysbiosis (a disturbance of the gut microbiota)

  • altered function of the intestinal mucosa (and of its immune and inflammatory functions)

  • visceral hypersensitivity to distention (excessive pain perceived when bowels are bloated)

  • potential central nervous system dysregulation (there's a strong link between GI symptoms of IBS and psychological stress)

A causal trigger is rarely identified, except for IBS after an episode of gastroenteritis, or stomach flu, where some might notice IBS symptoms appearing days or weeks after the resolution of the infection. Almost all of the other cases of IBS are sporadic, meaning they appeared out of nowhere, without any obvious cause. Let's take a look at the potential triggers that could play a role in the pathogenesis of sporadic cases of IBS. If you'd like to understand the basics of the microbiome before we deep dive in its pathophysiology, check out the gut health section of or click here!


The term dysbiosis is used to describe an imbalance in someone's gut flora, or microbiome. We now know that the gut bugs living in your colon aren't innocent bystanders. They are living organisms that feed on the foods that make it to the colon and in return produce healthy or harmful compounds, depending on what they're feeding on. As a general rule, "good" bacteria feed on fiber, and then produce beneficial compounds like SCFA (short chain fatty acids). These compounds play an important role in mediating immune function and inflammatory response in our gut and beyond. "Bad" bacteria are those that feed off of animal products and lead to release of toxins and inflammatory compounds like TMAO, instead of anti-inflammatory ones like the previously mentioned SCFA. In short, good bugs eat fiber (and other microbiota accessible carbohydrates, or MACs) and produce good things and bad bugs feed on processed crap and animal products and produce bad inflammatory compounds.

In a nutshell, eating unhealthy foods will typically lead to overpopulation with "bad" gut bacteria, aka those that lead to unwanted health outcomes, whereas a fiber friendly diet will lead to increases in gut bugs associated with production of anti-inflammatory compounds that promote gut health and many other health benefits throughout our body. The beneficial compounds produced by our good gut bugs help keep the gut lining air tight and makes it less "leaky". They also help modulate immune and inflammatory response, and they make the bowel nerves less sensitive to pain from distention.

Dysbiosis can be caused by physical stressors, like poor dietary patterns, antibiotics, food additives or preservatives, or by psychological stressors. Once there's a loss of "good" bacteria in your gut, it can take up to 6-8 weeks of consuming fiber rich foods, resistant starches and polyphenols before it can be reset. For some, the damage is done and a healthy microbiome will never be fully recovered. The issue with dysbiosis is that it often leads to avoidance of the foods most associated with gut health. For example, if someone who has dysbiosis eats a cup of beans, there's a great chance that the gut bugs required to "digest" these beans aren't present in sufficient numbers to digest them efficiently. This can lead to bloating, cramping and other symptoms labeled as food intolerance. The issue isn't the beans, but the dysbiosis. The food intolerance is merely a symptom of an unhealthy gut flora. Don't panic, there are many ways to reverse this, and avoiding beans and other healthy legumes is not the answer!


Leaky gut is simply a trendy and catchy way of describing altered gut mucosa function and permeability. The gut lining, or mucosa, is made out of a single layer of cells, called colonocytes. They're tightly packed together, side by side, interlinked by proteins we call "gap junctions". These proteins control the permeability, or leakiness, of our gut mucosa. In the context of dysbiosis, it is now well recognized that these proteins get severely degraded, making the thin gut lining hyper-permeable, or leaky. Unwanted chemical compounds are more likely to enter our blood circulation. Dysbiosis is one of the major causes of altered gut function, and leads to loss of its immune and anti-inflammatory functions. We know that IBS patients seem to have more mast cells, a type of immune regulating white blood cell, in their intestinal mucosa, which is a highly plausible mechanism for explaining the altered gut function and increased sensitivity to gut distention. The mast cell activation related to certain foods could very well be the cause for increased pain perception with bloating in the IBS patient, as well as microscopic mucosal inflammation in the gut lining. Leaky gut isn't a diagnosis, and doctors shouldn't be throwing this term around. Leaky gut is more of a sign that something else is wrong! To learn more about leaky gut, consider following experts like @theguthealthdoctor, or @theguthealthmd on IG.


In the context of dysbiosis and gut hyperpermeability, one can easily assume that a pro-inflammatory environment will be more likely to lead to unwanted gastrointestinal symptoms. Bowel distention, or bloating and stretching, is much more likely to cause pain in this context. Abdominal pain is the main symptom of IBS leading to medical consultation. Patients with IBS don't seem to produce more gas than non-IBS patients, they are simply hypersensitive to gut distention, leading to increased perceive pain and bloating compared to the same distention in a non-IBS patient. The production of gas related to food fermentation is identical in both IBS and non-IBS patients, it's simply their pain sensitivity that is different. Gas is a normal part of food fermentation by bacteria, and it doesn't have to be painful.


Anyone who has experienced butterflies in their stomach can appreciate how our mental health and guts are linked. This is explained by neural pathways travelling through the vagus nerve that connects them both. The vagus nerve (also known as the 10th cranial nerve or CN X) is a very long nerve that originates in the brain stem and extends down through the neck and into the chest and abdomen. It carries both motor and sensory information, and it supplies innervation to the heart, major blood vessels, airways, lungs, esophagus, stomach, and intestines. Have you ever fainted in stressful situations, after seeing blood or needles for example? That's the vagus nerve with its friendly reminder that complex thought processes are completely intertwined with our physical selves. It's not just "in your head" We are now realizing that this connection is a two-way street, and that the connection is not only through nerves, but through the bloodstream too, where the chemicals produced by our gut bugs travel. We call the latter the microbiota-gut-brain axis. The gut-brain axis (GBA) consists of bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centers of the brain with peripheral intestinal functions. Everyone has gotten butterflies in their stomach on the first day of school, or a rumbling tummy before a final exam. The gut and brain are linked together by nervous and biochemical or hormonal connections.

IBS is described as a functional disorder, meaning that no structural or biochemical damage can be found, and that the symptoms result from complex interactions between you gut and your brain. This is very different from saying that it's all in your head. We do know that mental health and IBS go hand in hand, and that many psychosocial factors will affect the symptom frequency and severity. People with a history of depression or anxiety, as well as other mental health issues, are known to have a higher likelihood of being diagnosed with IBS.


Most people that have IBS will link their symptoms or attacks to certain foods. But that doesn't mean that these foods are the root cause. One must remember that food intolerance are simply a symptom of the underlying disorder. If your gut reacts violently to certain foods, and that all the tests and investigations are normal, maybe it's not the food that's the problem.


The clinical management of IBS is done through a step-wise approach. The first step consists of seeing your doctor in order to rule out the other common contributors to chronic GI symptoms. These could include: IBD (Crohn's or ulcerative colitis), lactose intolerance, celiac disease, etc. Secondly, healthy dietary pattern modifications should be the next step. Alcohol, caffeine, spicy and excessively fatty foods and smoking should be cut back as much as is practical, since they've all been linked to symptom appearance. General healthy eating advice should then be considered, like minimizing ultra-processed foods, limiting red and processed meats as well as dairy.


Animal products, in particular animal protein, typically feeds gut bugs that are associated with the production of inflammatory compounds, like TMAO. Fiber fed bacteria are the ones that we consider the "good" gut bugs, considering the beneficial SCFA they produce. If you're not familiar with the gut microbiome, I definitely recommend you check out the Microbiome section of my website here, for a useful refresher that will help understand many upcoming concepts.


Since lactose intolerance is so pervasive, dairy avoidance is frequently recommended to most people presenting with chronic and non-specific GI symptoms. But one must recognize that dairy can cause gastrointestinal symptoms through different mechanisms, including milk protein allergy, that most commonly presents in early childhood. Some will present with malabsorption symptoms, like in lactose intolerance, where there is an inherent or acquired deficiency in the lactase enzyme that digests the milk sugar lactose. Some will simply have IBS, where the problems aren't related to milk allergy or to lactose intolerance, but dairy products in excess still seem to trigger attacks.


Let's say you join the gym. Instead of starting low and going slow, your stubborn personality peer-pressures you in to impressing the person next to you. The next day you can't lift your arms! You wouldn't blame the gym and decide to avoid it forever, when you know it's good for your health. That seems to be the problem with fiber. Often, patients come in my office with complaints of constipation. Some have decided to take matters in their own hands by drastically increasing their fiber intake, either through food or supplements. Most people regret it. Not because it's a bad idea, but because their guts were not equipped to cope with the rapid increase of fiber. If you're increasing the amount of dietary fiber too quickly, your gut is simply not ready for it. The "good" bacteria in your gut takes 6-8 weeks to grow, multiply and become efficient at digesting the increased fiber. It doesn't happen overnight. You gut will not be able to digest all that fiber and the ensuing increase in gas and water will lead to painful distention and cramps. The issue wasn't the fiber per se, but a gut microbiome that wasn't strong enough to handle the increased "weight". So, much like you would increase exercise intensity slowly in the gym, increase fiber super slow, over a span of 1-2 months. This should cause much less symptoms and the healthier microbiome will digest fiber and sugars more efficiently, leading to a healthier gut that can better withstand digestion and bloating with decreased pain.


Fodmaps are simple sugars that we can't properly digest, much like fiber. We don't have the enzymes encoded in our DNA, but do you know who does? Yes, our gut bugs! They digest them for us. Now let's say you have dysbiosis, aka a loss of balance in your gut bugs. You then eat certain foods that contain these simple sugars. What do you think happens? If you don't have the right gut bugs in significant amounts, gas (mixed with water formed through osmotic effects) gets produced through the fermentation process and gut distention occurs, followed by pain and flatulence, which is the medically-politically correct term for farting. This causes pain in IBS patients, leading them to believe the food's the problem, instead of the broken microbiome. FODMAP is simply an acronym meaning "fermentable oligosaccharides, disaccharides, monosaccharides and polyols". These are all small and simple sugar-like molecules that our colon doesn't digest well, and so we rely totally on our gut bugs to do the job for us. If our gut microbiome sucks, our guts aren't happy digesting these foods.

Low FODMAP diets are short term gains used to manage symptoms, associated with long term pains. Read that again. Low FODMAP diets are not necessarily healthy long term, but can be a trade off for better symptom management. When used long term, these restrictive diets are associated with dysbiosis, the actual thing we are trying to heal. The goal is simply to reset the gut, so we can reintroduce FODMAP containing foods slowly and keep them under the threshold where pain is triggered. FODMAP foods are used by bacteria and are associated with increases in the healthy type of gut bugs. Restrictions in FODMAP will be associated with loss of gut bug diversity, decreased SCFA (short chain fatty acid) production and possible deficiencies in vitamins, minerals and other phytonutrients. SCFA are vital to promote the growth of healthy gut bugs, and they are anti-inflammatory compounds that contribute greatly to the maintenance of a healthy gut barrier. They increase thickness of the protective gut mucus layer as well as increasing the tightness of gap junctions, which are proteins that help bind colonocytes and make the gut less permeable, or leaky.

People need to recognize that avoiding FODMAPS should always be a temporary solution and should always be followed by a reintroduction phase to test the threshold where the symptoms recur. If FODMAP containing foods are reintroduced slowly, along with foods promoting the growth of good gut bugs, one could possibly completely reverse the food intolerance and increase digestibility. Since the microbiome shift towards a healthier one takes 6-8 weeks, a dietary intervention such as the low-FODMAP diet, should be done under the supervision of a qualified dietitian. There should be 3 phases: 1) high FODMAP foods are limited to improve symptoms 2) FODMAP foods are reintroduced slowly and thresholds for symptom recurrence are determined for specific foods and 3) a long term plan is established where we attempt to strike a balance between symptom management, quality of life and nutritional adequacy, without being overly restrictive. Go see a qualified dietitian!

A low FODMAP diet should be tried only once the patient has been thoroughly investigated and has had structural medical conditions ruled out. After this initial step, simple dietary modifications like those previously mentioned should have also been tried for symptom improvement. Only then should a low FODMAP diet be attempted, while recognizing that this diet is not a diet for life. This pattern of eating is not a healthy way of eating over the long term, but should be seen for what it is, a clinical dietary intervention, where symptom management is the goal. Then, there has to a conversation about the pros and cons of pursuing this dietary pattern, knowing that many FODMAP containing foods are super healthy. They also feed the good gut bacteria in our colon and could help reverse the dysbiosis that caused the symptoms in the first place. About 50-70% of people trying this dietary pattern will see measurable improvements, but that still leaves a significant amount of people still in pain.


People with celiac disease have a gluten allergy and should absolutely avoid it. Some also have documented gluten sensitivity and in these people, reducing the amount of gluten under the threshold that triggers the symptoms would be a great recommendation. For everyone else, there’s absolutely zero, I repeat zero reasons to avoid gluten containing foods. Talking about gluten would require a full article in itself, and that will come soon. But it's important to recognize that when people decide to avoid gluten, they are also unknowingly decreasing their FODMAP containing foods. That's not saying that gluten isn't the culprit, but that gluten-free diets are only indicated in people with gluten allergy, aka celiac disease, or gluten sensitivity. If these two diagnosable conditions have been ruled out, then there's no reason to avoid gluten. None. Studies done on healthy patients (without celiac disease or gluten intolerance) while comparing gluten to placebo and measuring their GI symptoms have failed to show any significant benefit to removing gluten from one's diet. So in conclusion, if you think you have gluten allergy or intolerance, see your doctor. And if your symptoms get better on a gluten-free diet, it is still highly likely that gluten isn't the problem.


Fiber supplements and probiotics have been used for a long time to support gut health. If you remember the mechanisms that cause symptoms in IBS, you'll notice that improvement in gut bugs, gut function, gut permeability and gut sensitivity takes time. Fiber and probiotics can absolutely help, if part of a healthy dietary pattern. Since it takes weeks to significantly shift your gut bugs towards a healthier population, you can safely assume that probiotics for a week will never sustain a healthy gut flora over the long term. The probiotics will simply die off if not nourished and fed a high fiber diet. Both should be used together, along with a plant-rich diet, with limited animal products and processed food. What's the use in supplementing with probiotics (which are live "good" gut bugs in capsule or liquid form) if the underlying diet isn't able to provide these bugs with the food they need to multiply, grow and self-sustain. For a more detailed review of the microbiome, including probiotics, please refer to my website, and check out the Microbiome section here.

Other prescription drugs can be considered for symptom relief. They typically act on the muscle layer of the intestinal lining, and reduce cramps and pain. Others work by increasing gut motility in the patient with IBS and constipation symptoms, and by decreasing the activity of pain sensing nerves. Meds for IBS play an important role in symptom management, maintenance of quality of life and treatment of dietary resistant cases, but one must not ignore that dietary interventions are the mainstay of long term treatment and disease management.


You read that right! Many alternative therapies, like yoga, meditation, exercise, hypnotherapy, as well as cognitive behavioural therapy, or CBT, have all been found to improve IBS symptoms.


IBS is a very complex disease where many factors come into play. Dietary interventions are the mainstay of treatment, once more serious medical conditions have been ruled out. Unfortunately, many do not seek help with chronic and disruptive symptoms, but simply make unnecessary dietary modifications by themselves. I've seen patients brag about their all-meat diets curing their symptoms and relieving their bloating, not realizing that avoiding fiber, FODMAP foods, or other sources of complex carbohydrates have set them up for diseases much worst than IBS. A healthy gut microbiome has been linked to lower cardiovascular risk, less cancer, less diabetes, less obesity, less allergies and less auto-immunity, just to name a few. Consult your doctor and ask for a referral to a dietitian if you suspect that you may have IBS. All-meat diets lead to growth of pathogenic gut bacteria, production of secondary bile acids, which are highly carcinogenic, as well as a very unhealthy shift in the type of bacteria in your microbiome, not to mention the significantly increased risk of colon cancer, all of which have been proven without a shadow of a doubt. People who still think that eating an all-meat diet is healthy are simply uneducated on the matter, or delusional. Avoid the temptation to self-diagnose, go see a professional.

Check out my website and look for the “How To” section in the menu. There, you’ll find free `tips and tricks that helped me on my journey towards a plant-predominant diet. Everything there is completely free, no catches!

Look for me on the socials, @plantbased_dr_jules on Instagram and go like my Facebook Page, Plant-based Dr. Jules. If you’re looking for some fitness motivation and are curious to see what a plant-based athlete can accomplish, follow me, @maritimeninja, on my fitness account on Instagram or check out my fitness group on Facebook, called Maritime Ninja Warrior. I'm a two-time world championship qualified athlete and you can follow my fitness journey there! You can even access the resources section by becoming a member. It's free and there, you can download free resources like my plant-based recipe eBook!

You also check out my YouTube channel here for more tips and tricks on how to embark on a plant-based journey!

Thanks so much for reading!

Plant-Based Dr. Jules 💚🌱

Thanks so much for reading!

Please share your thoughts below! If you've improved your IBS symptoms through dietary modification, I'd like to hear about it in the comments!

Plant-Based Dr. Jules💚🌱

Saha L. Irritable bowel syndrome: pathogenesis, diagnosis, treatment, and evidence-based medicine. World J Gastroenterol. 2014 Jun 14;20(22):6759-73. doi: 10.3748/wjg.v20.i22.6759. PMID: 24944467; PMCID: PMC4051916.

Staudacher HM, Whelan K. The low FODMAP diet: recent advances in understanding its mechanisms and efficacy in IBS. Gut. 2017 Aug;66(8):1517-1527. doi: 10.1136/gutjnl-2017-313750. Epub 2017 Jun 7. PMID: 28592442.

El-Salhy M, Hatlebakk JG, Hausken T. Diet in Irritable Bowel Syndrome (IBS): Interaction with Gut Microbiota and Gut Hormones. Nutrients. 2019 Aug 7;11(8):1824. doi: 10.3390/nu11081824. PMID: 31394793; PMCID: PMC6723613.

Varjú P, Farkas N, Hegyi P, Garami A, Szabó I, Illés A, Solymár M, Vincze Á, Balaskó M, Pár G, Bajor J, Szűcs Á, Huszár O, Pécsi D, Czimmer J. Low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet improves symptoms in adults suffering from irritable bowel syndrome (IBS) compared to standard IBS diet: A meta-analysis of clinical studies. PLoS One. 2017 Aug 14;12(8):e0182942. doi: 10.1371/journal.pone.0182942. PMID: 28806407; PMCID: PMC5555627.

Palmieri B, Vadala' M, Laurino C. Gluten-free diet in non-celiac patients: beliefs, truths, advantages and disadvantages. Minerva Gastroenterol Dietol. 2019 Jun;65(2):153-162. doi: 10.23736/S1121-421X.18.02519-9. Epub 2018 Dec 14. PMID: 30545212.

Didari T, Mozaffari S, Nikfar S, Abdollahi M. Effectiveness of probiotics in irritable bowel syndrome: Updated systematic review with meta-analysis. World J Gastroenterol. 2015 Mar 14;21(10):3072-84. doi: 10.3748/wjg.v21.i10.3072. PMID: 25780308; PMCID: PMC4356930.

Ford AC, Harris LA, Lacy BE, Quigley EMM, Moayyedi P. Systematic review with meta-analysis: the efficacy of prebiotics, probiotics, synbiotics and antibiotics in irritable bowel syndrome. Aliment Pharmacol Ther. 2018 Nov;48(10):1044-1060. doi: 10.1111/apt.15001. Epub 2018 Oct 8. PMID: 30294792.

Simon E, Călinoiu LF, Mitrea L, Vodnar DC. Probiotics, Prebiotics, and Synbiotics: Implications and Beneficial Effects against Irritable Bowel Syndrome. Nutrients. 2021 Jun 20;13(6):2112. doi: 10.3390/nu13062112. PMID: 34203002; PMCID: PMC8233736.

Fond G, Loundou A, Hamdani N, Boukouaci W, Dargel A, Oliveira J, Roger M, Tamouza R, Leboyer M, Boyer L. Anxiety and depression comorbidities in irritable bowel syndrome (IBS): a systematic review and meta-analysis. Eur Arch Psychiatry Clin Neurosci. 2014 Dec;264(8):651-60. doi: 10.1007/s00406-014-0502-z. Epub 2014 Apr 6. PMID: 24705634.

Chey WD, Kurlander J, Eswaran S. Irritable bowel syndrome: a clinical review. JAMA. 2015 Mar 3;313(9):949-58. doi: 10.1001/jama.2015.0954. PMID: 25734736.

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Mar 10, 2022

Thank you

I developed IBS at the age of 50 after my first colonoscopy (routine screening) . my colonoscopy showed diverticulosis and I blamed the preparation for the increased stool frequency. I had cramps bloating and 5-12 liquid bowel movements a day For two years. I started removing dairy and animal products from my diet, added kimchi, komboucha and fermented foods to my diet. This seem to offer me the greatest return to a healthy bowel routine. I personally have found stress, fatigue, exercise patterns along with diet are all triggers for this frustrating often unpredictable syndrome .

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