Low FODMAP Makes Reflux Worse?

If you are new to this site, you should first read my How I Cured My Silent Reflux article as it explains the underlying root causes of acid reflux, its corresponding treatments, and provides the necessary context to follow some of the concepts in this episode.

Episode Transcript

(Note this is not a word-for-word transcription - it's loosely paraphrased. Alternatively, feel free to watch on YouTube).

Welcome to Episode 6 of The Reflux Cycle Show.

“The low FODMAP diet has been published in international medical journals and is now accepted and recommended as one of the most effective dietary therapies for IBS.”

This, according to Dr. Sue Shepherd of ShepherdWorks.com, one of the diet’s inventors.

The diet was created in Melbourne Australia, in the early 2000’s as a way to manage painful bloating and gas, characteristic of irritable bowel disorders.

When I first heard of it, however, I discounted it completely because people were telling me they were not allowed to eat fiber on the diet. It just didn’t make sense to me given the essential role fiber plays to restoring and maintaining a healthy gut.

In this show, I’ll explain that paradox, and what can be done about it. But first, I need to remind you that this show is for informational purposes only, and to provide ideas for you and your physician to research. It is not intended as individualized advice to treat, cure, mitigate or prevent any medical condition.

One more thing. Be sure and give this show a thumbs up and subscribe. It would be even more amazing if you would leave a review on iTunes. Right now the show is number 175 in the Alternative Health category and with your help we can get this important information out to more people who need to hear it.

With that, let me cover some of the basics of the diet. If you are already familiar, feel free to jump ahead using the time-stamps in your player or in the description below.


FODMAP is an ugly acronym that stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols, which are short-chain carbohydrates (sugars) that the small intestine absorbs poorly.

The term FODMAP doesn’t show up on food labels, and so there have been numerous books and internet resources put up to categorize foods as low or high FODMAP.

With that listing of foods in hand, dieters typically begin the first phase of a two phase plan. Phase 1 consists of restricting all high FODMAP foods for 4-6 weeks.

In the second phase, restricted foods are gradually reintroduced to determine which FODMAPs an individual can tolerate. FODMAPs exist across all food groups including vegetables, fruits, meats, dairy, grains, nuts, seeds, legumes, condiments, sweeteners, and drinks. I’ll give you just a few examples:

Category High FODMAP (avoid) Low FODMAP (ok)
Vegetables & Legumes Garlic, Onions, Asparagus Broccoli, Carrots, Cabbage
Fruits Apples, Apricots, Ripe Bananas Unripe Bananas, Blueberries, Grapes
Meats Sausages, Processed Meat Beef, Chicken, Lamb
Milk & Dairy Cows Milk, Ice Cream, Yogurt Almond Milk, Coconut Milk, Soy Milk
Grains Wheat foods, Granola, Muffins Oats, Rice, Popcorn
Nuts & Seeds Cashews, Pistachios Almonds, Peanuts, Pecans
Condiments Hummus, Jam, Relish Soy Sauce, Tomato Sauce, Mustard
Sweeteners High Fructose Corn Syrup, Honey, Xylitol Sugar, Glucose, Sucralose
Drinks Sodas, Herbal Tea, Fruit Juices Beer, Coffee, Chocolate Powder

That said, there are hundreds of foods on the list and some are listed with specific serving sizes. For a downloadable pdf, see my link to ibsdiets.org in the show notes.

Disclosure: This is a free website so I do advertise to cover the costs of website hosting and other services. If you find the information on this site useful, please consider making a purchase using the following links as I will earn a small commission at no cost to you.

Clinical Results

The problem is the low FODMAP diet has been shown clinically to increase microbial imbalance of the gut in just 4 weeks time. IdealNutrition.com explains that the low FODMAP diet is.

“a very restrictive diet that limits a whole host of healthy foods that would otherwise nurture and improve our gut health. [In particular the diet restricts a] number of foods that are prebiotic rich. This is because fructans and galacto-oligosaccharides (GOS) are prebiotic fibres.”

Let me share with you the results of several studies on the topic.

American Gastroenterology Association Clinical Trial

The American Gastroenterology Association published an article last year that shared the results of a clinical trial of Low FODMAP diet.

They performed a randomized controlled trial of 52 individuals to investigate the effects of a low FODMAP diet on gut symptoms and the microbiome.

A little over half 50% of patients reported some relief of gut symptoms following the low FODMAP diet as compared to 16% in the control diet.

However, in just 4 weeks, stool samples revealed significantly lower strains of Bifidobacterium (among others) as compared to the control group.

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Another Study

In another study, by the Vall d’Hebron Research Institute in Barcelona Spain, researchers compared the effects of a low-FODMAP diet with a placebo supplement vs a prebiotic supplement and a Mediterranean-type diet for 4 weeks.

“As expected, the low-FODMAP diet improved IBS symptoms (such as pain, distension, bloating, and flatulence), but decreased Bifidobacteria, in line with previous studies. Bifidobacteria increased 2 weeks following discontinuation of the low FODMAP diet, showing this change was transient.”

This underscores the importance of prebiotic fibers, so lets talk about how you can ensure that if you are doing a low FODMAP diet, you are still able to ingest the prebiotic fibers your body needs to begin healing.

Meta Study

In a meta-study published on MDPI, a publisher of peer reviewed medical journals, took a look at 13 different randomized control trials and 2 open label studies.

These studies investigated the impacts of high and low FODMAP on patients with irritable bowel syndrome and colorectal cancer.

The journal article correctly points out the inherent conflict between the health promoting benefits of non-digestible fibers and the low FODMAP diet.

One of the first things I noticed in this meta-study is this quote:

“In addition, lower Bifidobacterium abundance has been linked to abdominal pain in healthy individuals and IBS patients. Given that most of the studies indicated improvement of symptoms, these results hold an interesting paradox, specifically, that a dietary intervention that seems to benefit the patient regarding symptoms also results in a reduction in Bifidobacteria, which are positively correlated with pain relief.”

This means, people on low FODMAP diet may be gaining short term relief from avoiding pain associated with excess fermentation in the intestines, only to have that pain increase in severity and frequency once Bifidobacterium populations are further depleted.

The article continues

“Since FODMAPs are a major energy source for colonic microbes, bacterial loads can be expected to vary with FODMAP intake. Such effects are indeed noted in healthy individuals, where high fiber diets or prebiotic supplementation are associated with higher bacterial densities and/or higher fecal volumes”

In other words, the body relies on key bacterial strains such as Bifidobacteria to ferment prebiotic components and stimulates growth of other beneficial species through cross-feeding.

A healthy ecosystem of bacteria is key in modulating immune function, producing compounds essential for cell energy, producing and converting hormones, managing inflammation, gut function, gut permeability, and more.


The good news is the meta-study reveals that probiotics can help to partly counteract the changes. Additionally increasing non-digestible carbohydrate intake can be applied to ensure adequate prebiotics. The study notes that

“symptoms reappeared immediately in patients after quitting the low FODMAP diet, while patients of the prebiotic arm experienced reduced symptoms for 2 additional weeks. This suggests prebiotic supplementation might be a viable treatment option for those who can endure the initial start-up phase.

Sadly, none of the studies extended beyond 4-8 weeks, so long term results are yet to be studied.

Sow how does one continue with low-FODMAP while ensuring adequate prebiotic dietary fibers? A great article by dietvsdisease.org explains how to maintain a healthy gut microbiome on the low FODMAP diet.

I will include a link to it and a few other articles on this subject, in the show notes. the article explains that

“The low FODMAP diet excludes a lot of prebiotic foods because many of [them] are high FODMAP.”

Recognizing this, it is important to eat a variety of low FODMAP high-fiber foods. Examples include:

Category Low FODMAP (ok)
Vegetables & Legumes Cabbage, Chickpeas, Black beans, carrots
Fruits Raspberries, Green Bananas
Grains Quinoa, Wholegrain rice
Nuts & Seeds Chia seeds, Pumpkin seeds, Almonds

Additional articles:


So its clear that fiber, diversity of diet, and potentially probiotics are key to rebuild or maintain bacterial balance while doing a low FODMAP diet. But what can compromise that plan?

To answer that I’ll share a story with you from a few months ago.

My 12 year old son actually dealt with painful gas and IBS like symptoms once or twice per week for most of his life. He has several extended family members on my wife’s side going back to his great grandmother, that have dealt with these painful symptoms for their lives.

For a long time we just thought it was hereditary. It wasn’t until I began researching reflux that I started to believe we could intervene. Because of his age we took our time with deciding what to do as we were hesitant to experiment with him or try something too crazy.

We didn’t do a low-FODMAP, but we did do probiotics and ensured he ate a fiber rich diet. We did one other thing that I believe was key to his recovery. We planned for him to do a 30 day course of probiotics and while doing so were strict to avoid all sugar. This was enough to rid him of the painful gas that he experienced much of his life.

I share that to point out that other poor dietary choices such as those that contain refined sugars, sugar substitutes, high fat, processed foods, food triggers that lead to inflammation, not to mention stress, medications, and other risk factors can hinder progress.

A more comprehensive approach may be needed for individuals with more advanced stages of IBS / IBD.

Please let me know your thoughts in the comments. Should I keep doing these podcasts? What subjects are you most interested in?

Show notes for this episode can be found at theacidrefluxguy.com/006. My name is Don, and this was another episode of The Reflux Cycle. Signing off.

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Don is a best selling author of 'How I Cured My Silent Reflux,' and a former acid reflux sufferer for more than 15 years. With several family members with the disease, and a medically diagnosed hiatal hernia he resigned to the fact that he would take acid blockers for the rest of his life. Dissatisfied with medical advice, he researched the root causes of acid reflux and by solving them was able to eliminate his acid reflux for good!
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