Can a low FODMAP diet plan help resolve IBS symptoms?

If you are suffering from symptoms like bloating or diarrhea, chances are your doctor may have recommended that you try the low FODMAP diet. And you may be thinking  “what even is a FODMAP?” or “do I need to be on this diet forever?” or “what am I going to cook for myself and my family?” or “is going on the low FODMAP diet even going to help my symptoms?” Not to worry! We are going to go through what the low FODMAP diet entails, and some helpful tips and resources to make this low FODMAP elimination diet process easier. 

What is the low FODMAP diet plan?

The low FODMAP diet has quickly become the most common dietary intervention for Irritable Bowel Syndrome (IBS). For good reason, since about 70% of IBS patients report reduced symptoms once they started the diet plan. Despite its usefulness, there can be a large amount of confusion on what you can eat, length of time this all takes, and more. For now, just know, this dietary change is temporary!!

What are FODMAPs?

FODMAP is an acronym for Fermentable Oligo-, Di-, and Monosaccharides And Polyols. These are long names for carbohydrates (sugars) that travel through the gut partially undigested and then ferment in the colon. This fermentation causes unwanted digestive symptoms in IBS individuals such as diarrhea, constipation, gas, and bloating to name a few. 

Where are FODMAPs found?

FODMAPs are found in a wide arrange of foods such as fruits, vegetables, grains, dairy products, legumes, nuts, and certain sweeteners. Who decides this you may be wondering? The answer is that a laboratory measures the FODMAP content. Monash University is the main laboratory and they tell us how much of each food is safe! Let’s look at some specific food examples.  There are 5 primary FODMAP groups that fall under those long carbohydrate names. (Please remember this list above is abbreviated. More detailed information will be provided during your appointment with your registered dietitian).
  1. Oligosaccharides
    1. Fructans—wheat, garlic, onion
    2. GOS—legumes and some nuts
  2. Disaccharides
    1. Lactose-milk, soft cheese, yogurt, ice cream
  3. Monosaccharides
    1. Fructose—honey, apples, mango
  4. Polyols
    1. Sorbitol—apples, pears, avocado
    2. Mannitol—cauliflower, mushrooms, celery
Now that we have examples of what foods contain FODMAPs, let’s walk through how this all comes together to improve your quality of life and reduce those unwanted digestive symptoms’. This is completed in a phasal approach: the elimination phase, challenge phase, and modified diet phase.

The low FODMAP Diet Phases

Your dietitian is an integral part of this process, so be sure to consult someone rather than starting on your own! It can be confusing.  

Phase 1: FODMAP Elimination Phase

The FODMAP elimination phase is the first, and some think the hardest phase since high FODMAP foods will be replaced with lower FODMAP foods. The first phase lasts 2-8 weeks until symptoms are controlled! The goal is to have a minimally restrictive diet that can aid in controlling symptoms.  The phase should not be continued long term for many reasons. That’s where phase 2 of the approach comes in!

Phase 2: FODMAP Challenge Phase

The challenge phase, as the name implies, is when we begin to trial each FODMAP group one by one to determine personal tolerance. The base low FODMAP diet will be maintained during this process until you finish all challenges.  Some dietitians will have different approaches to this, but I typically use a 3-day challenge followed by a 3-day washout (back to the low FODMAP diet). Then onto the next group! You and your dietitian will decide which group, how much, and when to do each challenge. If all goes well, this phase can take around 8 weeks. 

Phase 3: Modified low FODMAP Phase

Once we complete all of the individual and combination food challenges, we will now incorporate the tolerable groups into your diet, while avoiding the group(s) that caused symptoms! This is your long term, individualized approach.  The good news is that FODMAP tolerance can change over time so if a particular group didn’t go well, try it again in a couple of months to see if anything has changed.

I’m feeling better after Phase 1, do I have to add high FODMAP foods back in?

It might be tempting to stay in the FODMAP elimination phase long term, especially if you noticed significant symptom relief and don’t want to risk experiencing GI symptoms again.  But eliminating large groups of food for extended periods of time opens you up to potential nutritional deficiencies like calcium and magnesium. There is also a possibility that the long term restriction can affect the healthy bacteria in your gut, which can make your digestive issues worse.   As you can see, the low FODMAP diet can seem confusing, but with a dietitian to educate and support you, symptom management is possible!  We also included some of our favorite low FODMAP resources below to help you through the process! 

Low FODMAP Resources

Low FODMAP Blogs Low FODMAP Recipes 

Kathleen Tabb is a registered dietitian based in Maryland. She specializes in digestive conditions such as irritable bowel syndrome (IBS) and has extensive training through her master’s degree in integrative and functional nutrition. She is passionate about looking at her clients holistically to illuminate the root cause of their concerns in order to improve health and quality of life