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Diets for IBS

IBS Diet Plans with Low FODMAP Foods

Modifications in diet can play an important role in treating patients who have IBS. By eliminating and reintroducing certain types of foods, dietary modification can often be an effective tool to help identify and alleviate common IBS symptoms. 


Because we now know that food can be a trigger for causing or worsening IBS symptoms, finding out which foods cause this disruption in your gut is important in designing the right long-term diet plan for you. Some common diet adjustments that your healthcare provider might suggest include reducing your gluten and fiber intake, avoiding sulfuric foods, restricting dairy consumption, and/or lowering alcohol consumption. The most popular diet treatment for IBS is a finely tuned menu of low-fermentable foods. 

The American College of Gastroenterology Clinical Guidelines for Managing Irritable Bowel Syndrome recommend “a limited trial of a Low FODMAP Diet in patients with IBS to improve global symptoms.”

What Is the Low FODMAP Diet?

The Low FODMAP Diet is a food category diet based on research conducted at Monash University, one of Australia's leading public research universities. Researchers at Monash have found that up to 75% of people with IBS feel better on the Low FODMAP Diet during the elimination phase.


Highly fermentable foods are filled with short chain carbohydrates that don’t get fully absorbed by the small intestine and in turn start to ferment in the colon, exacerbating IBS symptoms. The Low FODMAP Diet is a three-phase diet designed to help you eliminate, reintroduce, and avoid foods with these types of carbohydrates. 


Monash University defines the FODMAP acronym as:


Fermentable -  The process of bacteria in the gut fermenting unabsorbed carbohydrates into gas

Oligosaccharides (Fructans) - Found in foods such as wheat, rye, onions, garlic, and legumes/pulses

Disaccharides (Lactose) - Found in dairy products like milk, soft cheeses, and yogurts

Monosaccharides (Fructose) - Found in honey, apples, and high-fructose corn syrups


Polyols (Sorbitol and Mannitol) - Found in some fruits and vegetables and used as artificial sweeteners


In the first phase of the Low FODMAP Diet, the patient eliminates all highly fermentable foods from their diet for 2-6 weeks. In the second phase which lasts 8-12 weeks, the patient slowly reintroduces fermentable foods one at a time. This allows the patient to identify the exact foods that could be contributing to their IBS symptoms. 


In the final phase, patients will have a better understanding of which foods they should avoid and consume and can then integrate this change into their daily lifestyle, hopefully leading to less intrusive IBS symptoms. 


Here is a list of common foods to avoid under the Low FODMAP Diet. 

According to the review, Microbiome and Its Role in Irritable Bowel Sydrome, "FODMAP restriction is associated with reduced fermentation and significant symptom improvement in a subset of IBS sufferers.” 


What is Low Fermentation Eating?

Low Fermentation Eating (LFE) supports a more balanced microbiome by decreasing the amount of the fermented foods in a patient's diet. Developed by Mark Pimentel, MD and Ali Rezaie, MD, LFE is specifically designed for those patients suffering from SIBO and IBS symptoms like bloating, gas, constipation, and diarrhea.

Low Fermentation Eating is based on two parts: restricting foods with high carbohydrates and meal timing. When carbohydrates cannot be properly broken down, the bacteria in the gut then digest the sugars, releasing gases like hydrogen, methane, and hydrogen sulfide that can result in frustrating GI symptoms. Additionally, spacing out meal times with four to five hours between consumption allows for gut-cleaning waves.


Non-absorbable common sugar substitutes like sucralose, sorbitol, lactitol, xylitol, mannitol, and stevia are some of the top foods to avoid, because they cannot be digested by humans and instead feed the bacteria in the gut directly. High-fiber foods and foods with inulin, a type of prebiotic, are also considered troublesome. Foods like lentils, beans, soy products, and dairy products like milk, cheese, and yogurt are considered “fermentable” foods, as they can be difficult to digest and excessively feed the bacteria in the gastrointestinal tract. They should be avoided, as well.

The gut is self-cleaning, and it’s very important not to disrupt these natural gut-cleaning waves with food digestion. The gut-cleaning waves cannot occur until fasting. The feeding part of digestion ends within three hours of eating, and it’s suggested to have two gut-cleaning cycles before eating again. That means that leaving four to five hours between meals can support a more regular and proper cleaning cycle.

To learn more about Low Fermentation Eating (LFE) and get tasty recipes, please visit

The Value of an IBS Diagnosis for Dietary Modification.

A positive result on an antibody blood test for IBS can indicate that a diet low in fermentable foods could be effective in relieving your symptoms. An IBS diagnosis can also confirm you are on the right treatment plan and provide the motivation to comply with your dietary changes as you start to feel better.


An antibody blood test for IBS measures the levels of two antibodies that are IBS biomarkers: anti-CdtB and anti-vinculin. If these antibodies are elevated, IBS can be diagnosed with up to 100% positive predictive value. This diagnosis can also help you avoid potentially unnecessary tests and procedures that simply rule out other diseases. 

With your antibody results, your doctor can develop a personalized treatment plan that targets your microbiome, combining medication, lifestyle, and dietary changes so that you can start feeling healthy as quickly as possible. 

ibs-smart is the only licensed, patented antibody blood test for IBS.


The ACG Clinical Guidelines for Managing IBS suggest “a positive diagnostic strategy as compared to a diagnostic strategy of exclusion for patients with symptoms of IBS to improve time to initiate appropriate therapy.” ibs-smart offers a positive diagnostic strategy. 


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