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Low-FODMAP Diet

Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) are poorly absorbed dietary carbohydrates associated with gastrointestinal symptoms due to their fermentability and influence on intestinal fluid retention. A low-FODMAP diet temporarily reduces and then systematically reintroduces FODMAPs and has shown efficacy for reducing general symptoms of irritable bowel syndrome (IBS).

Our evidence-based analysis on low-fodmap diet features 34 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
Last Updated:

Summary of Low-FODMAP Diet

Primary information, health benefits, side effects, usage, and other important details

What are FODMAPs?

FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These are poorly absorbed, highly fermentable carbohydrates that can contribute to gas, bloating, and diarrhea due to their fermentability and attraction of water in the intestinal tract.

Click here to read more about specific FODMAPs and how they function in the intestines.

If you’re wondering about the differences between FODMAPs, fiber, and prebiotics, you’re not alone! Click here for a quick breakdown.

Which are low-FODMAP foods and which are high?

Many foods contain moderate to high concentrations of FODMAPs, with serving sizes dictating the overall FODMAP load. The way a food is prepared can also modify the FODMAP content. Meats and oils are almost always low-FODMAP foods. Fruits, vegetables, nuts, beans, grains, and many protein bars contain different types and amounts of FODMAPs, but some FODMAP categories are predominant in certain foods. Fructans are the main FODMAP found in wheat products, for example.

FODMAPs

Dietary FODMAP content can be confusing, so click here to read more about the most common sources and their low-FODMAP replacement options.

What is a low-FODMAP diet?

The low-FODMAP diet is thought to improve GI symptoms by reducing the content of FODMAPs in the intestines, resulting in lower intestinal water content and diminished gas production from microbial fermentation. It also modifies the gut microbiome, but the clinical significance of these changes is unknown. [1] Though it can be implemented in a variety of ways, the diet generally consists of an initial restriction phase, during which low-FODMAP foods replace those that are moderate or high, followed by a systematic reintroduction process to assess tolerance for each of the FODMAP groups. Dietary FODMAP sources are gradually elevated and diversified based on individual tolerance.

If you want to learn more about how to safely implement a low-FODMAP diet, click here.

Who is a good candidate for a low-FODMAP diet?

The low-FODMAP diet has been shown to improve quality of life as well as general IBS symptoms, including abdominal pain, bloating, diarrhea, and flatulence (though it is likely more effective for individuals with diarrhea-predominant IBS). [2] A short-term low-FODMAP diet may also reduce acute GI distress (commonly cramping and diarrhea) associated with intense endurance exercise. [3] Low-FODMAP formulas may also improve nutritional status in patients receiving enteral nutrition. [4] Additionally, in people with celiac disease, low-FODMAP, gluten-free diets are also associated with greater improvements in GI symptom scores compared with a gluten-free diet only.[5]

For reasons that are still unclear, people respond differently to a low-FODMAP diet, and some don’t see any improvements at all. Emerging research suggests that the fermentation capacity of a person’s microbiome might be one factor that explains—or could even predict—how well they’ll respond to a low-FODMAP diet. [6]

Click here to read more about the benefits of a low-FODMAP diet and how it compares to traditional dietary guidance for IBS.

Are there any risks associated with a low-FODMAP diet?

Long-term adherence to a low-FODMAP diet isn’t recommended, because it could be nutritionally inadequate and also appears to modify the microbiome in potentially unfavorable ways. [7] The low-FODMAP diet may pose a risk to people with inflammatory bowel disease (IBD), because they are already at risk of malnutrition.[8] The restrictive aspects of the low-FODMAP diet could also exacerbate an eating disorder. [9]

Click here to learn about the potential risks and limitations of a low-FODMAP diet.

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Human Effect Matrix

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The Human Effect Matrix summarizes human studies to tell you what effects Low-FODMAP Diet has on your body, how much evidence there is, and how strong these effects are.

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Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-c Strong Very High See all 12 studies
A low-FODMAP diet reduces global IBS symptom severity scores compared to a high-FODMAP diet, traditional Australian diet or placebo diet, but it is not always superior to traditional dietary advice for IBS or the modified National Institute for Health and Care Excellence guidelines (mNICE). The low-FODMAP diet appears to be more effective for IBS-D than IBS-C.
grade-c Notable Very High See all 5 studies
Relative and total abundance of Bifidobacterium are often lower after a low-FODMAP diet, but the changes aren't consistently significant. The clinical relevance of this change is unknown.
grade-c
Minor
- See all 5 studies
Markers of alpha-diversity have remain unchanged or increased after a low-FODMAP diet. The clinical relevance of this change is unknown.
grade-c
Minor
- See all 9 studies
In most cases, the low-FODMAP diet is associated with improved quality of life, and reduced activity impairment, sometimes correlating with reduced symptom severity. In some cases, quality of life is unaffected, and one study reported a reduction.
grade-c
Minor
Low See all 5 studies
In a few studies, low-FODMAP diets led to variable changes in fecal short-chain fatty acid concentrations. The clinical relevance of these changes is unknown.
grade-c Low See all 4 studies
The low-FODMAP diet is generally not associated with changes in beta-diversity. The clinical relevance this change is unknown.
grade-d Strong Very High See all 4 studies
The low-FODMAP diet is associated with reduced abdominal pain in healthy recreational runners, IBS, IBD, and Celiac disease compared to habitual diets, traditional dietary advice for IBS, and regular gluten-free diets.
grade-d Strong Very High See all 4 studies
A low-FODMAP diet consistently reduces bloating in individuals with IBS and IBD compared to habitual or control diets, and it is similarly or slightly more effective than traditional dietary advice for IBS.
grade-d Notable Very High See all 4 studies
A low-FODMAP diet is associated with reduced breath hydrogen production in healthy individuals and individuals with IBS, but changes in breath hydrogen have not been clearly or directly associated with IBS symptom severity.
grade-d Notable Very High See 2 studies
A low-FODMAP diet reduces flatulence compared to a high-FODMAP or habitual diet.
grade-d Minor - See study
A low-FODMAP diet may reduce markers of disease activity in individuals with CD, but this is based on limited evidence, and it is not superior to a standard diet.
grade-d Minor - See study
In healthy recreational runners, a low-FODMAP diet resulted in a slight reduction in reported day-to-day diarrhea occurrence.
grade-d Minor High See all 3 studies
A short-term low-FODMAP diet reduces GI distress during intense exercise compared to a high-FODMAP diet, but its efficacy during recreational exercise or in comparison to habitual diets is unclear.
grade-d Minor High See all 3 studies
Few studies have measured the effect of the low-FODMAP diet on fatigue, but it is associated with modest improvements in individuals with IBS.
grade-d Minor High See all 3 studies
A low-FODMAP diet is sometimes associated with reductions in the number of fecal microbes. The clinical significance of this change is unknown.
grade-d Minor Low See all 3 studies
A low-FODMAP diet doesn't consistently reduce disease-associated anxiety or depression.
grade-d
Minor
- See 2 studies
The effects of a low-FODMAP diet on IFABP have only been examined in runners, and the effects are unclear.
grade-d Minor Very High See all 3 studies
Stool consistency ratings are slightly lower (indicating more firmness) on a low-FODMAP diet.
grade-d
Moderate See 2 studies
A low-FODMAP diet is associated with either no change or an increase in breath methane in healthy individuals, and no change in individuals with IBS. The presence or absence of change is not associated with symptoms or other outcomes.
grade-d Moderate See 2 studies
A low-FODMAP diet does not consistently reduce FC levels in IBD.
grade-d - Very High See all 3 studies
A low-FODMAP diet does not appear to influence markers of inflammation such as T-cells, cytokines, or C-reactive protein.

Studies Excluded from Consideration

  • Compared to yoga with no control group [10]

  • The authors concluded that time, rather than the low-FODMAP diet, explained the results [11]

  • This was a mechanistic study to determine how FODMAPS would affect water and FODMAP content of the large intestine [1]

Things to Note

Is a Form Of

  • Diet

Primary Function:

Also Known As

Low-FODMAP

Goes Well With

Peppermint Oil

Caution Notice

IBS shares many symptoms with other GI diseases, so before starting a low-FODMAP diet, you should visit your gastroenterologist.

A low-FODMAP diet isn't recommended for individuals with IBD and could also pose a risk to people with eating disorders.

Click here to see all 34 references.