Irritable bowel syndrome (IBS) is one of those things millions of people worldwide are suffering from, but very few feel comfortable talking about – even in amidst a time where we’ve got poop emojis in our cell phone keypad. 😉 Either way, the phrase “IBS diet” is now being searched over 60,000 times per month worldwide… wowzah! Talk about unprecedented times. (Source: KeySearch, July 2022)
But in an ever-growing sea of online experts with conflicting opinions, how do you know which IBS diet is best for you? How can you decipher the fads and trends from the science?
In this 40-minute read, I’ll be sharing my opinions, perspectives, and insights on all things IBS diets as a holistic and functional dietitian nutritionist, and also as a former IBS sufferer. I’ll even do my best to distill down the clinical, sciency stuff to make it “digestible” for you! (Yup – pun intended).
(Updated January 1, 2023)
Disclaimer: This article is meant to be educational and informative. This information is not medical advice! If you have IBS or another type of gut health issue, make sure you’re working with a doctor and holistic dietitian / functional dietitian nutritionist to determine the best plan of care for your individual needs!
Affiliate disclosure: This article contains a few affiliate links*. As an Amazon Associate, I may make a commission from purchases made from qualifying purchases, at no extra cost to you.
What is IBS?
IBS is a functional type of “gut issue” that is usually diagnosed as a last resort, after medical conditions like inflammatory bowel disease (IBD) have been clinically ruled out by a doctor.
A global Gastroenterology study published in 2021 concluded that about 40% of the entire population has a gut issue of some kind (1) and according to Clinical Epidemiology, about 11% of people worldwide have IBS. (2)
Why address IBS with diet and nutrition?
Unfortunately in the conventional medical system, IBS is rarely addressed beyond the surface level (aka symptom management).
Pharmaceutical interventions are superficial and don’t offer much sanctuary, beyond temporary relief at times. (It’s no secret that the mainstream medical system profits from and focuses primarily on treatment, but not cure.)
But aside from being a pain-in-the-you-know-what (often quite literally), IBS is one of those things that you really shouldn’t leave unchecked for too long – for a few very important reasons!
Quality of life
While IBS symptoms often get minimized or brushed off in clinical settings, I understand first-hand how they can wreak havoc on quality of life physically, mentally, and emotionally.
And I also know how invalidating and frustrating it can feel to be told “you’re fine” over and over again, when you feel in your gut (in more ways than one) that something is clearly off!
Which leads into the next important reason you should address your IBS sooner rather than later…
All disease begins in the gut
According to Hippocrates, an ancient physician and philosopher, “all disease begins in the gut” – and we now know this to be very accurate.
- The gut is intimately synced with our immune system, brain, hormonal balance, detoxification, and more!
If we don’t get to the root of IBS or other gut issues early on at the cellular level, we’re at increased risk of developing what I often refer to as a “domino effect”.
The domino effect & collateral damage
Since everything in the body is interconnected, an unhealthy gut lining / gut microbiome left unchecked for too long can potentially snowball. In my experience and clinical case observations for over a decade, IBS usually precedes any or all of the following, which you’ll hear me refer to as ‘collateral damage’ (3, 4, 5, 6, 7):
- New onset food allergies
- New onset environmental allergies
- Oral allergy syndrome
- Food sensitivities
- Leaky gut syndrome
- Micronutrient (vitamin/mineral) deficiencies
- Chronic fatigue (from nutritional deficiencies left unchecked)
- Depression
- Anxiety
- Increased risk of autoimmunity
- Skin breakouts/rashes
- Gastritis
- Hormonal imbalance
- Diverticulosis (from constipation)
- Diverticulitis (from diverticulosis left unchecked)
- Fissures (from constipation)
- Hemorrhoids (from constipation)
- Esophagitis (from heartburn and/or food allergies/food sensitivities)
- …And more
Clearly, managing IBS and its underlying root causes properly is pretty darn important! So at this point, you’re probably wondering…
How can diet and nutrition help IBS?
Symptom management
A primary goal of IBS diets is to reduce and minimize unwanted symptoms.
IBS diets can provide a certain level of structure and framework as well as some relief. An IBS diet will take away some of the guess-work when it comes to pinpointing certain food culprits most likely to trigger symptoms or inflammation. They can also help you to narrow down the best food choices for your body!
Symptom management via dietary modification IS helpful and necessary as a piece of the journey.
But certain types of diets (aka the cookie-cutter handouts with the list of processed foods you may find in a mainstream hospital setting) will do little to address the underlying root-causes when it comes to chronic conditions like IBS.
There are some more holistic dietary approaches for IBS which will help you to address your condition at a deeper level; these work best when combined with a clinical therapeutic diet.
Food as medicine
“Food as medicine” is one of 6 pillars in my comprehensive gut-healing framework, which I refer to as the “Complete Gut Repair Roadmap.”
But keep in mind: food as medicine is not the same as a diet!
- Diets focus on restriction, while “food as medicine” focuses more on nourishing and supporting the body with the right balance of your own best foods, while also leaning on functional foods as needed.
That being said, the degree to which diet and nutrition help your IBS will depend on the degree to which the protocols are addressing your IBS at the root-cause level.
But before we go any further into the “meat and potatoes” of IBS diets, I want to make sure we first acknowledge that IBS diets (like any other health/nutrition protocol) are not for everyone with IBS!
Cons and limitations of IBS diets
Restrictive
Diets are restrictive by nature. And I’ve unfortunately seen dietary restrictions do more harm than good for a lot of people.
Even the “best” IBS diet on paper still has the potential to lead to nutritional deficiencies and/or an unhealthy relationship with food, aka disordered eating and eating disorders. (8)
While I’m not an “anti-diet” dietitian, since everyone is different and some people benefit from the guidelines and parameters of therapeutic diets, it’s imperative to make sure you have a healthy relationship with food, body image, and self-care before embarking on any kind of diet.
Not sustainable
Sustainability is the “secret sauce” when it comes to healing your gut via nutrition and food-as-medicine! Sustainability is how you set your body up to heal itself, by living holistically over months and even years, since healing takes time.
The caveat? Diets are usually pretty rigid, difficult to sustain, and not meant to be followed long-term.
- For example, the low FODMAP diet (which we’ll dive into very soon!) is meant to serve as a “stepping stone” for a few months’ time while on an IBS healing journey.
Not to mention, life is dynamic! Diets are not.
- When happy hour or vacation rolls around, I’ve seen a lot of IBS diets go out the window, when they lack flexibility and sustainability.
The key to sustainability is to take what you need, leave the rest, use your discernment, listen to your body, and ultimately convert a rigid diet into a sustainable, flexible, dynamic and holistic lifestyle over time.
Blindspots and pitfalls
In the world of nutrition and diets, most people are seeing everything from a 2-dimensional lens.
- It’s kind of like the analogy of obsessing over the weeds and trees, and missing the forest – aka the big picture.
- In other words, most people tend to fixate too heavily on the bells and whistles around what NOT to eat – and they miss the boat on the big picture of what they really need, from a holistic (multi-dimensional) standpoint.
As a result, lots of people end up making unhealthy, unbalanced food choices just because certain foods are on the “allowed” list of foods to eat. It’s like trying to cheat the system but at your own expense.
(When there are too many rules, it’s easy to lose sight of the intention of trying an IBS diet, which is usually so you can start to heal and feel better.)
Exhibit A
I’ve witnessed people go on a Paleo diet and opt to live off bacon, eggs and burgers for breakfast, lunch, and dinner – because all of those foods are “allowed.”
- A diet like this is likely not feeding any pathogenic (“bad”) gut microbes – but it’s also not doing much for health or wellbeing in any other way. (A diet without enough fruits, veggies, carbs, or healthy fats is not the solution to IBS!)
Exhibit B
Another example of falling into nutritional blindspots and pitalls would be someone on a low-fat diet choosing to eat a highly processed, sugary fat-free cereal with skim milk for breakfast, a turkey sandwich on white bread with a diet soda for lunch, and a big bowl of plain pasta for dinner – because they can. (Need I say more?)
These types of blindspots and pitfalls do people a huge disservice and ultimately hold them back from nourishing their body in a way that actually promotes healing.
Not customized
While diets are started with good intentions and goals to serve specific purposes, it’s important to keep in mind no diet is customized!
Cookie-cutter diets don’t take into account your individual food preferences, food allergies, sensitivities, or intolerances.
In my opinion, diets always require some level of customization and modification in order to account for your individual needs – especially if you’re on a gut-healing journey.
All of that being said, it’s important to remember that no diet as a stand-alone intervention is going to be a “be all end all” solution to your IBS!
So are they even worth exploring?
I’ll let you decide…
Types of IBS Diets
Now that you have a better understanding of how diets can help or hurt your IBS prognosis depending on the context, you’re ready to learn my “two cents” on some of the most popular and/or up-and-coming IBS diets!
I’ll be getting on my soapbox and sharing my professional low-down on each of the following:
- Low FODMAP
- Specific Carbohydrate Diets (SCD)
- Paleo
- Whole30
- The GAPS diet
- High fiber
- Low fat
- Gluten free
- Lifestyle Eating & Performance (LEAP)
- Ketogenic (“keto”) diet
- Low fiber
Disclaimer: Again, this is not medical advice! I’m not necessarily endorsing or recommending all of these diets. I’m just shining light on some relevant information, pros, and cons of each IBS diet from a clinical and holistic nutrition standpoint, so you’ll be more equipped to make informed decisions alongside the guidance of your IBS treatment team.
Low FODMAP
This diet is the #1 nutrition intervention most often prescribed by gastrointestinal (GI) doctors and gut health dietitians.
The purpose and premise of the low FODMAP diet is to reduce IBS symptoms of gas and bloating as much as possible.
But before we go any further into the low FODMAP diet, let’s answer the burning question: what the heck does FODMAP mean?!
- “FODMAP” stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. (I dare you to try saying that 10x fast!)
- FODMAPs are fermentable short-chain carbohydrates which are found to feed “bad” (troublesome) microbes in the intestines, leading to fermentation in the intestines, followed by a subsequent release of methane gas as a bi-product.
- The methane getting released in the intestines by these troublesome microbes is a major underlying culprit of gas, bloating, and digestive discomfort among many IBS sufferers.
Which foods are allowed on the low FODMAP diet?
This diet doesn’t single out or villainize any one specific food group (i.e. carbs, proteins, fats, fruits, veggies, etc.).
However, the low FODMAP diet is still very complex and restrictive in that it excludes certain foods from almost every food group. The foods left out of this diet are those which are most notorious for triggering symptoms of gas and bloating.
Allowed foods: wheat-free grains, lactose-free dairy, small amounts of certain types of beans, all animal-based meats/proteins, all oils, certain types and certain portions of nuts/nut butters, non-cruciferous veggies, and low-fructose servings and types of fruits and sweeteners.
Restricted foods: wheat, lactose-containing dairy (cow’s milk, goat milk, ricotta cheese, etc.), most beans, lentils, high-fructose types or amounts of fruits, high-fructose sweeteners, avocado, most cruciferous veggies (cauliflower, cabbage, brussel sprouts, and large quantities of broccoli), and most alternative non-sugar sweeteners.
Pros and cons of the low FODMAP diet
The biggest “pro” of the low FODMAP diet is it is often very effective at alleviating symptoms of discomfort among lots of people with IBS. (Of course that’s a huge win!)
On the other hand, the low FODMAP diet is also:
- Very restrictive
Difficult to sustain - Not customized
- Ineffective for some people
- Not very holistic
- For example, corn syrup and cane sugar are “allowed” on this diet, and these sugars may still feed dysbiotic microbes in the gut that contribute to IBS at the root-cause level.
While some people find relief from partially or strictly following a low FODMAP diet, others may feel better after being on a variation of a “specific carbohydrate diet” (SCD).
Specific carbohydrate diets (SCD)
“Specific carbohydrate” is essentially a category of primal-style diets which emphasize whole, minimally processed foods while restricting grains, beans, dairy, and most types of sugar.
Grain-free, specific carbohydrate diets are typically more extreme and restrictive compared to the low FODMAP diet, but far less confusing and complex.
The purpose of a SCD approach is to optimize the microbiome by depriving dysbiotic microbes of their food, while reducing inflammation and nourishing the body.
Types of specific carbohydrate diets for IBS
While there are dozens of variations of SCD out there, the three most common versions of SCD specifically for IBS are:
- The Paleo diet
- Whole30
- The “Gut and Psychology Syndrome” (GAPS) diet
There’s a great deal of overlap between these diets, to the point where outsiders looking in wouldn’t notice any difference. But for the purpose of this article I made sure to break it all down for you!
Paleo
The Paleolithic Diet or “Paleo” diet was designed based on the concept that we return back to our roots and eat the way our ancestors did during the times of the Stone Age.
This diet really started becoming popular and gaining traction in the last few decades which followed the publishing and launching of The Paleo Diet: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat (a book by Loren Cordain) back in 2002.
Which foods are allowed on the Paleo diet?
This diet is very basic in that it consists primarily of:
- All fruits and 100% fruit juices
- All veggies
- Tubers (potatoes)
- Nuts
- Seeds
- Animal protein (meat, chicken, pork, poultry)
- Seafood
- Eggs
- Natural unrefined sweeteners (i.e. raw honey, coconut palm sugar, agave nectar, and real maple syrup, stevia leaf extract, and monk fruit extract)
The Paleo diet doesn’t allow any of the following:
- Grains (wheat, corn, barley, rye, rice, quinoa, amaranth, buckwheat, etc.)
- Processed sugars
- Dairy
- Legumes
- Artificial sweeteners
Since 2002, multiple offshoots of the Paleo diet have started taking off and gaining ground – especially Whole30.
Whole30
The Whole30 program is a spinoff of the Paleo diet.
This variation of Paleo was cofounded in 2009, as a result of co-founder Melissa Hartwig Urban’s blog about her own lifestyle overhaul and “dietary experiment” which led to more energy, improved digestion, and more.
The main intention of the Whole30 diet is to help reset and recalibrate the gut microbiome, metabolism, energy levels, and food cravings over the course of 30 days through eating only whole, minimally processed, nutrient-dense foods.
The Whole30 program is essentially 30 days of dietary restriction (within the set parameters of the diet), followed by 10 days of reintroduction of foods that are least likely to be suspected as “problematic”.
How is Whole30 different from Paleo?
In the Whole30 program, no natural sugars, alcohol, or sweet treats of any kind are “allowed”, even if made out of Whole30-compliant ingredients (i.e. dates, coconut, banana pancakes, etc.).
Whole30 does, however, allow ghee (clarified butter) which is not encouraged on the Paleo diet.
There are also particular lifestyle components to the Whole30 diet such as no stepping on the scale, weighing/measuring food, counting calories, or even buying everything organic. This component may be helpful for people who tend to hyper-fixate on weight and numbers, as it can allow them to reset and trust the way their body will respond to real, nourishing foods.
Whole30: food for thought
The Whole30 diet is an example of one that can make you feel amazing while sticking to the rules, but which is not very sustainable and not intended to be long-term since it’s so restrictive.
If you’re planning on giving this approach a try, you should have a very solid meal planning foundation in place, since it requires a lot of food prep!
You’ll also want to make sure you have some kind of “exit strategy” or step-down plan, so you don’t just fall back into the same dietary habits that were keeping you sick and stuck. (This is something you may want to do with a qualified coach, and with clinical supervision from your IBS treatment team!!)
GAPS diet
GAPS stands for “Gut and Psychology Syndrome”, which makes sense because the premise of this diet is that the gut and the brain are intimately connected. (This is why the gut is called our “second brain!”)
The main goal and purpose of the GAPS diet is to reduce inflammation, nourish and heal the gut lining, and rebalance the microbiome with a food-as-medicine approach. And when we heal the gut, we improve the function of the brain.
The GAPS diet was founded by a Russian neurologist, Dr. Natasha Campbell-McBride MD, who runs a holistic medicine practice based out of the United Kingdom. She has a dual degree in neurology and human nutrition. She was inspired to develop this diet independently of the Paleo diet, back in 2004 after her first son was diagnosed with autism.
- Dr. Campbell-McBride did extensive research on the gut-brain connection, the microbiome, leaky gut, and more, and came up with this very specific nutrition and lifestyle regimen to address dozens of chronic health conditions pertaining to the gut, and/or the brain, and/or the immune system (since everything is connected). Her son has since been free of autism.
How is the GAPS diet different from Paleo and Whole30?
The “bones” of this diet (pun intended – you’ll see) are very similar to Paleo and Whole30 in that the GAPS diet also restricts all grains, refined sugars, processed food, and most types of beans.
- In certain ways,the GAPS diet is even more restrictive than Paleo in that only raw honey and dates are allowed as sweeteners (no maple syrup or coconut sugar), and starches (such as potatoes and cassava) are not allowed. (This is because of Dr. Campbell-McBride’s findings on sucrose, starch, and their tendency to feed Candida among lots of GAPS patients.)
- On the other hand, while on the GAPS diet, you may still eat sprouted lentils, certain types of dairy as-tolerated (such as ghee, and most types of raw, unpasteurized dairy) in moderation, and small amounts of scotch and dry wine.
GAPS diet and functional foods
I find the GAPS diet to be more clinical and “food-as-medicine” heavy in that there’s a bigger emphasis on functional foods such as probiotic sauerkraut, copious amounts of meat stock and bone broth, and certain supplements as-needed.
(This makes sense, considering the diet was developed by a board-certified physician who has a double degree in neurology and human nutrition!)
The GAPS intro diet
There’s also an optional 6-phase GAPS introduction diet which is very limited.
People are encouraged to move through each phase and reintroduce only one food at a time until their bowel movements are mostly 3’s and 4’s on the Bristol Stool Chart.
Non-nutrition GAPS protocols
In her book, Gut and Psychology Syndrome: Natural Treatment for Autism, Dyspraxia, A.D.D., Dyslexia, A.D.H.D., Depression, Schizophrenia*, Dr. Campbell-McBride also discusses alternative therapies such as detox baths and enemas which are a bit controversial and which fall outside the scope of nutrition and diets, but which have been helpful and effective anecdotally for some people with more extreme conditions.
What’s up with the raw dairy?
On the GAPS diet, Dr. Natasha Campbell-McBride liberalizes raw dairy in moderation for those who can tolerate it.
This is because of claims and anecdotal reports that raw dairy is easier to digest for people with gut issues, because of the live enzymes and probiotics which aid in the nutritional breakdown.
On the other hand, raw, unpasteurized dairy is controversial because it runs the risk of harboring Listeria food poisoning. This is why pasteurization of dairy began in the first place.
In lieu of reading between the lines, I want you to keep in mind that cows didn’t really start harboring Listeria bacteria until the 1920s when industrial farmers began feeding dairy cows corn instead of grass, for the sake of mass production. (10)
- Cows’ digestive tracts are not designed to break down corn properly which is why in factory farms, more cows will get Listeria infections. (10)
- Proper hygiene and good food safety practices among farmers also seem to make a big difference in the prevalence of Listeria (or lack thereof) in raw milk (11).
When it comes to raw vs. pasteurized dairy, and dairy in general, there are clearly a lot of gray areas – it’s not “black and white”. I encourage you to do your research, listen to your body, use your discretion, and consult your treatment team to determine what is best for you!
My GAPS diet experience
The GAPS diet is the specific carbohydrate diet most near and dear to my heart. I actually followed this diet for almost two years! That journey was filled with many ups, downs, and everything in between. (Stay tuned for my personal GAPS diet review coming soon!)
Pros and cons of specific carbohydrate diets
The SCD approach (whether Paleo, Whole30, or GAPS) is clearly gaining traction because of the degree to which so many people are feeling better on these types of diets.
On the other hand, the main downside of these diets is they are very restrictive, difficult to sustain, and not customized.
- People who are prone to yo-yo dieting or disordered eating should steer clear of SCD approaches.
I’m also seeing a lot of people going on these diets just to be “healthy”, without any kind of clinical need for so many restrictions which is really unnecessary.
SCD takeaways
To be clear, I don’t recommend or endorse going on a grain-free, bean-free diet just to be “healthy” – but certain aspects of this approach (such as eating mostly real, minimally processed foods, and reducing refined sugars) could still be beneficial for the general population!
- If you’re just looking to eat “healthy” for the sake of living optimally, you may instead be interested in the Kitchen Alchemy: Holistic Nutrition Fundamentals self-paced online course to get the full scoop on balanced eating for optimal living.
Those who do pursue the SCD path for gut-healing purposes need to keep in mind it’s a long game, not a quick fix! Modifying these diets as-needed can go a long way for sustainability purposes.
It’s also important to note that just because certain types of carbohydrates are restricted on these diets, doesn’t mean you should be going “low carb”. You’ll need to find ways to meet your carbohydrate needs from carbohydrate-rich fruits, veggies, sweeteners, etc.
I also highly recommend working alongside a functional dietitian and/or holistic nutritionist for guidance, support, clinical supervision, and customization as needed.
High Fiber
Are you among the many who’ve been told to “just eat more fiber”? Have you been prescribed metamucil to increase your fiber intake? If so, you’re most definitely not alone!
A high fiber diet is one of the more “old school” approaches to managing IBS via diet modification. It’s been around way longer than low FODMAP or any of the grain-free diets – and for good reason.
Fiber is a unique type of carbohydrate which can’t be broken down by the human gut. Fiber is naturally found in most plant foods such as fresh fruits and veggies, beans, peas, lentils, nuts, seeds, and whole grains.
Fiber can be especially helpful for people with IBS-C because it serves to add bulk and volume (aka “roughage”) to stools.
A high fiber diet can also sometimes be beneficial for managing IBS-D or IBS-M, but it varies case-by-case. (I’ve seen some people with IBS-D thrive on psyllium husks, while others may find themselves running to the bathroom or doubled over in pain, and everything in between…)
Types of fiber
There are two types of fiber:
- Soluble fiber
- Insoluble fiber
Soluble fiber dissolves in water, which means it can make its way into the bloodstream. Soluble fiber is especially beneficial for heart health because it helps cleave and remove excess cholesterol from building up in blood vessels.
- People with IBS-D tend to tolerate soluble fiber better than insoluble fiber, because soluble fiber slows down activity in the digestive tract.
Insoluble fiber can’t dissolve in water, so it’s more likely to provide roughage for stools and speed up transit time. (“Roughage” is what adds bulk and volume of stool, helping to naturally improve regularity and detoxification.)
- Insoluble fiber tends to be more beneficial for people with IBS-C and IBS-M compared to IBS-D.
On a high fiber diet, people are generally encouraged first and foremost to listen to their body while leaning on a mix of soluble and insoluble fiber from foods.
What foods are allowed and restricted on a high fiber diet?
No foods are totally restricted on a high-fiber diet; however, certain types of foods or groups are still more encouraged than others.
The recommended foods on this diet are those containing at least 3 grams of fiber per serving.
This includes whole or minimally processed foods, such as:
- Fresh fruits
- Fresh veggies
- Whole grains
- 100% whole wheat
- Amaranth
- Barley pearls
- Brown rice
- Buckwheat
- Einkorn
- Forbidden rice
- Kamut
- Oats/oatmeal
- Quinoa
- Rye
- Spelt
- Wild rice
- Beans, lentils, and peas
- Avocado
- Nuts and seeds
Generally, fresh fruits and veggies with skins have more fiber than their peeled, cooked, or canned counterparts.
Functional foods for fiber
“Functional” foods (foods with a specific function or purpose) are another helpful way to boost fiber intake. Some of the most common fiber-rich functional foods for gut health include:
- Ground flax seeds
- Psyllium husks
- Chia seeds
Functional foods high in fiber can be easily added to yogurt, smoothies, or oatmeal.
Foods to minimize and moderate:
- Refined grains made with white, all-purpose flour or white rice
- Commercial desserts and baked goods
How much fiber is recommended?
Most healthy adults need between 20-38 grams of fiber per day, and sometimes, people experience IBS symptoms when they simply aren’t getting enough fiber from food. (Who knew?!)
- Women generally need about 20-25 grams of fiber per day.
- Men generally need about 25 to 38 grams of fiber per day.
Fiber and fluids
Increasing fiber can be easy, but it should be done gradually – and with a lot of fluids!
In a nutshell, fiber has the potential to swell in the gut and turn into a cement-like paste when we aren’t washing it down with enough fluids to push it through.
Drinking a “normal” amount of water (~8 glasses a day) plus other stuff like coffee or tea is usually enough to do the trick!
Pros of a high fiber diet
Flexible
A great thing about the high fiber diet is it’s very flexible and not too restrictive. A high fiber diet can be a great place to start if you’re navigating IBS and you don’t do well with too much rigidity.
Full of prebiotics
Most fruits, veggies, whole grains, and other high fibe foods also happen to contain prebiotics. These are undigestible carbohydrates which feed the “good” probiotic bacteria, which then produce beneficial short-chain fatty acids (aka “postbiotics”) in the gut. Prebiotics, probiotics and postbiotics all help with maintaining healthy gut function!
Fundamental
Getting enough fiber is fundamental for a healthy digestive tract.
And in this modern-day society, on the “standard American diet”, over 90% of people (with or without IBS) are missing the boat on fiber because they aren’t getting even a fraction of the fruits, veggies, and whole grains they need on a regular basis.
But at the same time, if a high fiber diet was really all it took for everyone to remedy IBS, we probably wouldn’t be having this conversation. 😉
Downsides of a high fiber diet
Nutritional blindspots
From a holistic lens, I see fiber as only ONE key ingredient of an entire gut-healing “recipe”.
- Metaphorically speaking, if the goal (or “recipe”) is to make an apple pie, perhaps the fiber is the apples – but you can’t make an apple pie with just apples, just like you can’t resolve IBS with just fiber!
Since most people view diets as two-dimensional (good or bad, right or wrong, healthy or unhealthy), they’re missing the many other dimensions of gut health that need to be taken into consideration.
High fiber and FODMAPs
A lot of the foods being promoted on a high fiber diet happen to also be pretty high in FODMAPs. (A few examples of high fiber, high FODMAP foods that are top-of-mind include beans, lentils, and whole wheat.) I’ve seen those specific foods often send many IBS sufferers spiraling into a flare.
- It can feel very confusing, frustrating and invalidating for someone with IBS to follow a diet that was prescribed by someone they trust, only to experience yet another flare.
Dysbiosis
Unlike the specific carbohydrate diets, which are all about depriving “bad” microbes from what they like to feast on, high fiber protocols don’t take into account the impact that certain “allowed” foods will have on gut microbes.
- For example, a lot of high fiber foods I often see being promoted are very processed and high in sugars and beans which tend to feed the “bad” microbes like Candida, for most people with underlying dysbiosis.
So in this sense, fiber may serve as one important piece of symptom management, but if you’re choosing high fiber foods that are feeding the “bad” bacteria in your gut, you’re going to stay stuck. It’s like treading water – you aren’t drowning, but you also aren’t moving forward.
Low Fat
The low fat diet is another common IBS diet recommended in mainstream facilities, because people with IBS tend to have a difficult time digesting rich, heavy, greasy foods with lots of butter or oil.
This diet can be helpful short-term for symptom management purposes, but again, it’s usually not enough as a stand-alone intervention.
Some factors to consider:
- Is this being caused by a deficiency in digestive enzymes, bile, or pancreatic enzymes?
- Is the gut pH suboptimal?
- Is the gut lining compromised?
Pros and cons of a low fat diet
A low fat diet is primarily used for symptom management. It may help provide some relief because you’re essentially avoiding foods that are making you feel worse.
However, a low fat diet does not promote healing and it’s not meant to be followed long-term.
Regardless of the fact that your gut may not be processing fats properly, your cells need fat! This is especially true for the brain and for hormone production. The brain is made up of ~60-70% fat, and fats play multiple vital roles in the body.
Fats also help us to feel full and satiated after meals – otherwise you may find yourself eating every few hours and still not feeling satisfied!
Lastly, fats help with vitamin absorption – specifically the fat-soluble vitamins A, D, E, and K. Without enough fat in the diet, we’re setting ourselves up for multiple vitamin deficiencies which leads back into the “domino effect” I mentioned earlier!
Gluten free
Traditionally, the gluten free diet is endorsed and recommended only for people with celiac disease; however, in recent decades, more and more people are finding they have a non-celiac gluten or wheat sensitivity.
Lots of doctors and nutrition coaches are recommending a gluten free diet for people with IBS, because it seems to provide at least some relief for a great deal of people (whether you have celiac disease or not!).
Which foods are allowed and restricted on a gluten free diet?
The gluten free diet is one which restricts/eliminates foods containing gluten.
(Gluten is a protein found in certain types of grains which include wheat, barley, rye, and triticale.)
Avoiding only four types of grains may sound very simple, easy, and straight-forward, but the gluten free diet is complex in that wheat is hidden in most types of processed food.
What to know before going gluten free
While lots of people (celiac or not) seem to find relief from cutting gluten out of their diet, it’s important to make sure you’ve ruled out celiac disease. (Don’t put the cart before the horse!)
- If you go gluten free first, before ruling out celiac disease, then you may get a false negative celiac test.
- Learn why that is not okay in my free gut health nutrition guide: 5 Diet Mistakes to Avoid When Healing Your Gut!
Should you go gluten free?
While there are millions of people swearing by the gluten free diet, it’s not that simple! Often gluten is not really the issue.
In my practice I’ve found that lots of people seem to have a non-celiac wheat sensitivity, which can get pretty tricky since these symptoms are pretty broad and overlap with lots of other issues. (IBS, fatigue, brain fog, headaches and joint pain come to mind!)
Wheat (a gluten-containing grain) is also considered to be high in FODMAPs, which makes things extra confusing and complicated for people who are trying to navigate whether or not they should be going gluten free.
You may likely feel better on a wheat-free and/or gluten-free elimination diet, but keep in mind this approach as a stand-alone intervention still won’t address the following:
- Other possible food intolerances/sensitivities
- Your gut microbiome
- Your gut lining
- Fiber
I’ve seen people live off of gluten free muffins, gluten free bread, gluten free pasta and gluten free desserts, and end up worse than they started.
It’s also possible to still heal your gut while keeping wheat and gluten in your diet in some cases. (This is determined on a case-by-case basis.) While going gluten free may help take away the guess-work, it could also be an unnecessary dietary restriction which is just an extra burden to carry and which increases the risk of micronutrient (vitamin/mineral) deficiencies.
If you choose to get on the gluten free bandwagon, make sure you’re doing it responsibly by:
- Understanding and embodying the holistic nutrition fundamentals (aka eating a balanced variety of real food!)
- Taking into account the full picture of complete gut repair (versus just getting lost in the bells & whistles of dietary restriction, which will just keep you stuck treading water in the Sea of Symptom Management!)
Lifestyle Eating & Performance (LEAP)
I decided to save the best for last… the Lifestyle Eating and Performance (aka “LEAP”) diet!
Also often referred to as the LEAP eating plan, “immuno-calm” diet, and the “oligo-antigenic” diet, this cutting-edge functional nutrition protocol is probably the least well-known but most important to know of all the IBS diets.
What is the LEAP diet?
LEAP is an exceptionally customized eating plan, which can only be designed by a certified LEAP therapist (CLT).
The premise of the LEAP diet is to design a plan of eating based on the results of your mediator release test (“MRT test”), which measures food sensitivity reactions.
- As I mentioned earlier in this article, food sensitivities are a common but little-known underlying culprit of IBS-D, and the MRT test is considered a gold-standard for identifying food sensitivities that induce an inflammatory immune response in the gut mucosa.
Who is the LEAP diet for?
Clinically, the LEAP diet is more relevant for people with IBS-D or IBS-M versus IBS-C, unless you’re also experiencing other symptoms of food sensitivity such as migraine, fibromyalgia, suspected colitis/gastritis, or an autoimmune disorder of any kind.
(Gas and bloating are actually not related to food sensitivities in most cases!)
Which foods are allowed and restricted on the LEAP diet?
Since the purpose of this diet is to match you to all of your body’s best foods, and this plan is designed based on your MRT blood test results + nutritional assessment (completed in advance with a CLT), each person’s list of “allowed” versus “restricted” / “limited” foods on the LEAP eating plan is going to be completely unique to them.
Allowed foods: those which are lowest on the measured reactivity level which you eat often and know your body tolerates well
Restricted foods: those which are moderate to high on the measured reactivity level
Like the low FODMAP diet and GAPS diet, the LEAP eating program also includes an optional but encouraged 6-phase elimination diet based on the MRT test and food-symptom journaling.
During each phase, one new food will be strategically re-introduced every few days.
Pros and cons of the LEAP diet
Great results
The LEAP diet has delivered life-altering results for those who are highly motivated and willing to implement what they learn from working with their CLTt!
- I’ve worked first-hand with people who had struggled lifelong with IBS-D and comorbidities for many decades, and were able to heal up to 90% in less than 3 months through meeting with me every week and following 90% of what was recommended on their LEAP eating plan.
Nutritionally balanced
While the variety of options is pretty limited in the early stages of this approach, your LEAP eating plan will include “safe” foods from all food groups.
Unlike most of the other diets which cut out certain food groups, the LEAP diet is all about maintaining nutritional balance while reducing inflammation and optimizing your microbiome through incorporating foods from every food group so you’ll get what you need from a macro- and micronutrient standpoint.
Clinical and customized
This diet is designed 100% based on your body, your food preferences, and your bloodwork!
The food-symptom journaling is also helpful as a clinical tool for providing real-time feedback and filling in the blind spots in regards to any food allergies and/or food intolerances, which aren’t measured or assessed in the MRT test.
Challenging!
On the other hand, this diet can still be extremely restrictive from a variety standpoint for the first few months, especially if you opt to go through the 6-phase elimination diet and you react to multiple foods. (Is ignorance bliss? I personally don’t think so, but you get to decide that!)
Since this diet in general (even without the 6-part elimination component) requires a great deal of planning and meal prep, it can feel like you’re living in a bubble for a few months.
Due to the great deal of time and $ this lifestyle overhaul entails, as well as the possibility of a learning curve when it comes to balanced meal planning (not to mention work-life-family balance), most people opt not to do the elimination diet, which can sometimes make it more difficult to get results!
Limiting
This eating plan is based off of a food sensitivity test which measures reaction levels to 170 different foods and chemicals. (That being said, there are lots more than just 170 foods and chemicals in our food and in body care products, too!)
Most people just want to cut out the “reds and yellows” from their MRT blood panel, since it’s the least restrictive option, and that leaves a lot of uncertainty when it comes to all the untested foods and chemicals.
- For example, hemp seeds, arugula, artichokes, and stevia are some untested foods that people often continue to eat. But what if they are still reacting to these foods? We wouldn’t know without the 6-phase elimination diet which most people opt to skip.
Like all other IBS diets, while the LEAP eating plan is certainly the most customized, if there are other underlying issues going on that aren’t addressed by nutrition (such as gut dysbiosis, a miswired nervous system, trauma, mycotoxins, mast cell activation syndrome (MCAS) or certain other medical conditions), it can feel disheartening to put in so much effort for not a ton of return on investment.
The LEAP eating plan is most effective when combined with other aspects of functional nutrition and gut repair protocols such as GI mapping, functional foods, nutraceuticals, and medical interventions, as needed.
Low fiber
In my experience, while some individuals with IBS-D may find relief from a low fiber diet, typically if you’re benefiting from this diet, it’s a sign you probably don’t have IBS – you likely have inflammatory bowel disease (IBD). (Make sure to consult a GI doctor to find out what’s going on either way!)
If you’re looking to learn more about the low fiber diet, I invite you to check out this comprehensive low fiber foods list PDF + article I co-wrote with my colleague, Katie Dodd of the Geriatric Dietitian!
What about the keto diet?
I figured it would be worth mentioning the ketogenic (“keto”) diet, only because so many people are exploring keto for IBS nowadays.
The ketogenic diet is essentially a very-low-carb, very-high-fat diet which has re-emerged as a weight loss and gut health trend over the last decade, since its inception in the 1920’s as a medical nutrition therapy intervention for people with epilepsy.
Keto is relatively similar to the Atkins diet, another low-carb diet protocol which was more popular in the 1990’s and early 2000’s.
- Both keto and Atkins tend to induce fast and extreme weight loss by putting people into a state of “ketosis” (which we’ll talk more about in just a moment!).
Which foods are allowed on the keto diet?
This diet restricts not just grains, starches and sugars (three primary sources of carbohydrate in the diet) but even most types of fruits and veggies. The traditional keto protocol recommends limiting carbohydrates to ~20 grams (one total serving of carbohydrate) per day.
There’s also a pretty heavy emphasis on not just the “healthy” fats (i.e. olive oil, flax seeds, fatty fish and avocado), but also on saturated fats from red meat, bacon, coconut, dairy, and more.
What is ketosis?
To set a precedent, the body needs a certain amount of carbohydrates, for energy and for the brain to function.
When the diet is too low in carbs and the body needs carbs, it will first break down glycogen (starchy carbohydrates stored in the liver & muscles) before resorting to ketosis.
Ketosis is the body’s natural way of making carbohydrates out of non-carbohydrate materials (i.e. fats from food and body tissue, as well as proteins from muscle and organ tissue).when you’re deprived of carbs for too long.
Making carbs out of fats and proteins is normal once in a while, but not very efficient. Ketones (aka “ketone bodies”) are a toxic bi-product released into the blood during ketosis. We need to eliminate ketones through our urine, so when the body can’t keep up, it creates a toxic burden to the kidneys and eventually other organs in the body.
Going into a state of ketosis is potentially dangerous and clinically unnecessary for most people aside from those with epilepsy and/or severe insulin resistance.
Does keto help IBS?
While there are anecdotal claims of people saying their gut feels “better” on a keto diet, it’s likely not because of the low-carb, high-fat protocol.
Any relief found from the keto diet is probably a result of removing all food sources of FODMAPs and processed sugars/starches known to feed pathogenic microbes in the gut.
That being said, given the dangers of ketosis and the macronutrient (carb, protein and fat) imbalances being promoted on the keto diet, I believe going on keto for IBS is very unnecessarily restrictive, clinically unsound, and potentially dangerous.
So, what’s the best IBS diet? (Key takeaways)
I believe most (but not all) of the above IBS diets have the potential to serve as a helpful “backbone” in functional nutrition and/or medical nutrition therapy, but they should always be modified and customized to fit the person. (Not the other way around!)
Since each diet as a stand-alone intervention is somewhat incomplete, I’ve found in my first-hand clinical experience that people most often benefit from a modified and customized combination of a few different IBS diets.
- I typically recommend what I believe is best for each of my 1:1 and small group coaching clients individually, based on many years of experience and clinical judgment.
If you’d like to narrow down your options, it can be helpful to start matching your symptoms and root-causes and/or your IBS subtype to one or more of the corresponding IBS diets listed above. Pay attention to what resonates most based on where you’re at.
- FYI – If you’re stuck on how to do this, I walk people through my step-by-step process via a Symptom Clarity + Root-Cause algorithm in module 1 of my Complete Gut Repair Roadmap online course!
Based on everything you just learned in this article, please take what you need and leave the rest from the following list (with help from your IBS treatment team as needed!):
Best option if you have an eating disorder
If you have a tendency towards disordered eating, please steer clear of all diets and work 1:1 with a certified eating disorder registered dietitian (CEDRD).
Best diets for IBS-C
- Low FODMAP
- Encompasses gluten free
- SCD (Paleo, Whole30, GAPS)
- High fiber
Best diets for IBS-D
- SCD (Paleo, Whole30, GAPS)
- LEAP
- Low fat
- High or low fiber (varies)
Best diets for IBS-M
- Low FODMAP
- Encompasses gluten free
- SCD (Paleo, Whole30, GAPS)
- High fiber
- Low fat
- Possibly LEAP
Clinically unsound diets for IBS
- Gluten free (unless celiac disease or non-celiac wheat/gluten sensitivity are present)
- The ketogenic (“keto”) diet
The bottom line & next steps
IBS diets have the potential to be helpful in providing structure and parameters, while minimizing potential trigger foods most likely to cause a flare.
However, diets alone are not a “Be-All-End-All” solution to IBS. Diets still need to be nutritionally balanced, customized and modified as needed, to promote gut-healing and sustainability.
Diets are not for everyone; the “dark side” of diets is they are restrictive and pose a risk of triggering disordered eating and/or nutritional deficiencies among some people.
You’ve probably also noticed: I didn’t give you a list of foods to eat/avoid – and that is because everyone’s gut is as unique as their fingerprint! One size never fits all.
Whether you’d like to explore IBS diets or not, I don’t recommend trying to figure this out on your own!
- Working with a functional medicine doctor and holistic gut health dietitian will spare you years of suffering and trying out all the piece-meal, incomplete cookie-cutter diets. (With all do respect, you don’t know what you don’t yet know.)
- You also don’t have to keep spinning your wheels or throwing things at the wall to see what sticks! You’ve done enough of that.
If you’d like to learn more about healing your gut naturally via my 6-part holistic and multi-dimensional approach, make sure to check out the following programs:
Cheers to a healthy gut and a better life!
XO – Jenna
