Food First Approach to IBS

Posted in Nutrition Tips / Irritable Bowel Syndrome / Low FODMAP

Food First Approach to IBS

Written by Brooke Bulloch, Registered Dietitian

If you've struggled with embarrassment and frustration of excess gas, abdominal bloating and pain, urgency to use the bathroom, and either constipation or diarrhea (or both!), you're not alone. The Canadian Digestive Health Foundation estimates that about 5 million Canadians suffer from Irritable Bowel Syndrome (IBS), however, many individuals suffer in silence. Let's be real, bowel issues don't make great table talk and there can be a lot of embarrassment around it.

IBS is a complex functional gut disorder where there are no structural issues, but something is wrong with how the bowel functions. This can relate to the brain and gut connection, type and amount of bacteria in your gut, and visceral hypersensitivity (ie. how a person senses digestion).


It’s important to speak with your doctor to get a formal diagnosis. This includes ruling out structural gut disorders such as colorectal cancer, celiac disease, crohn’s disease or colitis. Your doctor will complete a physical assessment and series of questions related to functional gut disorders. There is also a diagnostic criteria for IBS. In 2016, the Rome Foundation released a new diagnostic tool for IBS:

Recurrent abdominal pain on average at least one day per week in the last 3 months, associated with 2 or more of the following:

  • Pain related to defecation (ie. pooping)
  • Associated with a change in stool frequency (ie. having a bowel movement more often or less often)
  • Associated with a change in form (appearance) of the stool (ie. type 1 to type 7 using the Bristol Stool Chart)

Once you have a formal diagnosis, a dietitian trained in this area can then help you to figure out what your triggers are, and create a strategic plan to help manage your symptoms.

I often hear of people trialing various elimination diets on their own, cutting out many foods that are unlikely to be an issue but then have lingering trigger foods causing symptoms. And sometimes, food has little to do with IBS. Naturally, people get frustrated about food restrictions, not understanding what their triggers are, and not seeing improvements in symptoms.

Food First Approach to Managing IBS

The most popular, evidence based way to manage IBS is with the low FODMAP diet developed by researchers at Monash University in Australia. It’s not a diet in the way we think of weight loss dieting, rather it’s referred to as medical nutrition therapy. Studies show that, when explored properly with the help of a dietitian, symptoms can improve in ~75% of patients with IBS. The low FODMAP diet is complex because it's not based on eliminating specific food groups, rather, foods that contain moderate to high amounts of FODMAPs.

It's important to note that the low FODMAP diet is not appropriate for everyone, such as people who experience anxiety around food and eating, or for those with disordered eating habits (including eating disorders). A trained dietitian conducts a careful and thorough assessment to decide on the appropriate course of action. This may or may not include the Low FODMAP diet.

FODMAPs is an acronym for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are certain types of carbohydrates that people with IBS don't digest well. When FODMAPs enter the small intestine, they can attract excess water and if they reach the large intestine, the bacteria will rapidly ferment them. This leasds to symptoms people experience - diarrhea, pain, excess gas and bloating, and/or constipation. Foods that contain higher FODMAPs include (to name a few):

  • Oligosaccharides such as fructans (FOS) and galacto-oligosaccharides (GOS): garlic, onions, wheat, rye, cashews, and legumes like kidney beans
  • Disaccharides such as lactose: cows milk, regular yogurt, and soft cheeses like cream cheese
  • Monosaccharides such as fructose: honey, apples, pear, and high fructose corn syrup
  • Polyols such as mannitol and sorbitol: cauliflower, celery, blackberries, and avocado

It can be overwhelming and complex. The best chance at improving your symptoms and better understanding your food and non-food triggers is to work with a trained dietitian who can help to create a careful strategy, using the 3 phase approach:

  • Phase 1: reduce high FODMAP foods (swapping higher FODMAP foods for lower FODMAP alternatives) for about 2-6 weeks. The goal is symptom improvement.
  • Phase 2: challenge/reintroduce high FODMAP foods trackign symptoms. The goal is to identify trigger foods and portions.
  • Phase 3: long term management of the condition and personalization. The goal is to liberalize the diet as much as possible, limiting ONLY the foods that trigger symptoms. Long term strategies may include non-pharmacological agents such as prebiotic or probiotic supplements and other over the counter medications.

IBS is highly personal and requires a detailed assessment of the individual, careful planning, and follow up support as you navigate.

To inquire further or to book an appointment, contact Brooke Bulloch, Jacqueline Stickel, or Colleen MacKay (Regina).