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IBS Diet

The Digestive Wellness IBS Diet


Food is a major trigger of digestive symptoms, and you have no doubt noticed your symptoms worsen after a meal or eating certain foods. You may have pin-pointed a few foods that cause issues, but the rest usually remain a mystery.

There is so much information out there about what you should and shouldn’t be eating that it can become very confusing to know what’s right for you.

We find this to be a huge source of frustration for our clients, so we have devised an eating plan based on a framework of safe foods. These are foods known to cause the least reaction and reduce symptoms.

Our IBS Diet draws on the science and wisdom of a number of therapeutics diets, including:

  • Low FODMAP Diet
  • Specific Carbohydrate Diet
  • Fast Tract Diet
  • GAPs Diet
  • Autoimmune Paleo Diet
  • Body Ecology Diet

Fermentable Carbohydrates

We know there is a connection between food and the symptoms of IBS, but what researchers are discovering is that food alone isn’t the cause of the symptoms, rather when the environment of the gut is altered, by dysbiosis, SIBO, parasites, etc., symptoms may be exacerbated by certain components in the food

There is strong evidence that certain foods can contribute to the symptoms of IBS through the effects of malabsorption of carbohydrates. (3, 4) (Malabsorption is a failure to fully absorb nutrients from the gastrointestinal tract.)

Most of the food we eat is broken down into smaller parts and absorbed in the small intestine. However, our bodies don’t produce the enzymes needed to break down most complex carbohydrates, so our gut flora provides the enzymes needed for this.

As undigested food passes through the large intestine, the bacteria ferment it. This process produces short chain fatty acids, and results in the production of gases including hydrogen and methane.

The reaction that IBS patients get from eating certain foods has been attributed to their inability to fully absorb particular types of carbohydrates. Once they arrive in the lower small intestine and colon, these poorly absorbed carbohydrates provide the food for bacterial fermentation, which then leads to the gas, bloating, pain and general abdominal discomfort. (5)

Because some of these carbohydrates are in very small particles, when they are not fully absorbed they can affect the gut osmotically, causing more water to be delivered to the bowel. In some people, this leads to episodes of diarrhea.

In other people who have an overgrowth of bacteria in the small intestine (SIBO), when bacteria is fermenting certain types of carbohydrates in their small intestine, the gas being produced will bloat a very narrow section of the bowel, which causes abdominal distension, discomfort, bloating and pain.


Research has been accumulating that shows that IBS patients can be helped by excluding a group of food components from their diet known as FODMAPs. Evidence has emerged that FODMAPs can play a role in causing the symptoms of IBS. (6)

The term FODMAP is an acronym, which stands for Fermentable, Oligo-, Di-, Mono-saccharides and Polyols. These are short chain carbohydrates that are poorly absorbed in the small intestine.

One study found the restriction of dietary FODMAPs to be beneficial in reducing the symptoms of IBS in at least 74% of patients with IBS. (7)

In another study, researchers found:

“Restricting the intake of foods high in FODMAPs reduces the amount of colonic fermentation, gas production, and small intestinal fluid volume. Dietary therapy can, therefore, be directed toward reducing such gut distension by limiting both gas production and the osmotic effect.” (8)

Since bacteria use carbohydrates as their energy source and ferment them into gas, we have found a lower fermentable carbohydrate diet can directly reduce symptoms by decreasing the amount of gas produced. A reduction in fermentable carbohydrates forms the first phase of our eating plan.

Why extra fibre may not be helpful

For most people with IBS, especially those with constipation, one of the first recommendations they hear is to increase the fibre in their diet or to take fibre supplements. However, research and the experience of many patients show mixed results, and in some cases a worsening of symptoms.

For healthy people, the fermentation of fibre in the large intestine is considered healthy. Unfortunately, for people with digestive problems, consuming too much fibre may cause excess fermentation.

Research done at Addenbrooke’s Hospital NHS Trust, Cambridge, UK linked fibre with abnormal gut fermentation and determined that a fibre-free diet could significantly reduce symptoms and intestinal gas. (9)

A systematic review of the effectiveness of including different types of fibre in the diet of IBS patients being treated for constipation found only marginal benefits. In some cases, fibre actually worsened IBS symptoms. (10)

The Digestive Wellness Eating Plan

The first step of our eating plan is to reduce the consumption of fermentable carbohydrates.  Since we know that certain carbohydrates are malabsorbed by a large percentage of people with IBS, and that these carbohydrates feed bacterial overgrowths, it’s no surprise that studies show that removing foods that contain these carbohydrates from the diet will reduce symptoms of IBS.

We have found that using a combination of the FODMAPs Diet, Specific Carbohydrate Diet, and the Fast Tract Diet provides the most effective approach to reducing digestive symptoms and this forms the first phase of our eating plan.

It is important to note that, while removing fermentable carbohydrates will provide symptomatic relief for most people, it won’t address the underlying reasons for your symptoms, such as dysbiosis, SIBO, parasites or altered gastric secretions. The diet is mostly temporary and is designed to starve the pathogens, yeasts and parasites, and is most effective when used in conjunction with other treatments that address these conditions.

Other important goals of the diet are to reduce inflammation, assist the re-population of beneficial bacteria and to help repair the gut wall. In the second phase of our treatment plan, we carefully introduce certain medicinal foods, along with prebiotic and fermented foods, to further assist in this process.

We understand that making dietary changes can be challenging, so we have made the implementation of this IBS Diet as easy as possible, providing you with:

  • A list of safe foods
  • A list of foods to avoid
  • Sample meal plans
  • Meal planning template
  • A recipe book PDF with over 100 recipes
  • Ongoing food symptom diary analysis to fine tune diet

Knowing what foods you should and should not be eating will give you a great sense of relief. As your treatment progresses and you start clearing up the cause of your symptoms, you will be able to re-introduce a lot of foods that you previously found problematic.

What next?

To learn more about the testing and treatment options available to you we recommend you take a free 15 minute phone consultation with our Naturopath. During this call you can learn more about our treatments and have any questions you may have answered. This call is to determine if we are a good fit for one another rather than a history or complete consultation. There is no obligation, and no strings attached.

It is quick and easy to book your free 15-minute phone consultation using our online calendar. Just click the link below, choose a date and time convenient for you, enter your details, and our Naturopath will call you at your chosen time. Book here




  1. Simrén M, Månsson A, Langkilde AM, Svedlund J, Abrahamsson H, Bengtsson U, Björnsson ES. Food-related gastrointestinal symptoms in the irritable bowel syndrome. Digestion. 2001;63:108-115
  2. Bohn, L., Storsrud, S., Tornblom, H., Bengtsson, U. & Simren, M. Self-reported food-related gastrointestinal symptoms in IBS are common and associated with more severe symptoms and reduced quality of life. Am. J. Gastroenterol. 108, 634–641 (2013).
  3. Barrett J.S., Gearry R.B., Muir J.G., Irving P.M., Rose R., Rosella O., et al. (2010) Dietary poorly absorbed, short-chain carbohydrates increase delivery of water and fermentable substrates to the proximal colon. Aliment Pharmacol Ther 31: 874–882
  4. Shepherd S.J., Parker S.C., Muir J.G., Gibson P.R. (2008) Randomised, placebo-controlled evidence of dietary triggers for abdominal symptoms in patients with irritable bowel syndrome. Clin Gastroenterol Hepatol 6: 765–771.
  5. Dear KL, Elia M, Hunter JO. Do interventions which reduce colonic bacterial fermentation improve symptoms of irritable bowel syndrome? Dig Dis Sci. 2005 Apr;50(4):758-66.
  6. Gibson PR, Shepherd SJ. Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach. J Gastroenterol Hepatol. 2010 Feb; 25(2):252-8.
  7. Shepherd SJ, Gibson PR. Fructose malabsorption and symptoms of irritable bowel syndrome: guidelines for effective dietary management. J Am Diet Assoc. 2006 Oct; 106(10):1631-9.
  8. Muir, JG, Gibson, PR. The Low FODMAP Diet for Treatment of Irritable Bowel Syndrome and Other Gastrointestinal Disorders. J Gastroenterol Hepatol. 2013 Jul; 9(7): 450–452.
  9. Bijkerk CJ, Muris JW, Knottnerus JA, Hoes AW, de Wit NJ. Systematic review: the role of different types of fibre in the treatment of irritable bowel syndrome. Aliment Pharmacol Ther. 2004 Feb 1; 19(3):245-51.
  10. Markland AD, Palsson O, Goode PS, Burgio KL, Busby-Whitehead J, Whitehead WE Association of low dietary intake of fiber and liquids with constipation: evidence from the National Health and Nutrition Examination Survey. Am J Gastroenterol. 2013 May; 108(5):796-803.


The Digestive Wellness Clinic
12 Junction St Woollahra, NSW 2025 Tel: (02) 8001 6344