Dietitian Tips to Get in More Fibre on The Low FODMAP Diet

Struggling to get in enough fibre when following the low FODMAP diet? Here are some tips to bump it up!  

The low FODMAP diet has become one of the top dietary recommendations for improving IBS symptoms, and for good reason! Studies have shown it can reduce IBS symptoms in 3 out of 4 individuals. Although this is great news, many people go on the diet without appropriate support or knowledge which can result in inadequate nutrition, particularly low fibre intake. 

As a Registered Dietitian specializing in digestive health, I see many folks who struggle to get adequate fibre on the low FODMAP diet resulting in discomfort from constipation and potential changes to their gut microbiota.

Keep reading to find out fibre’s connection to IBS and the low FODMAP diet as well as high fiber low fodmap foods to implement into your diet and more additional recommendations. 

Why is Fibre Important and How Much Do I Need? 

It is recommended you consume 25 to 38 grams of fibre per day. Fibre is important in the diet and has multiple benefits. One of the main benefits is that it keeps our gut bacteria happy by providing a food source. The bacteria ferment the fibre and produces healthful byproducts such as short chain fatty acids which are used as an energy source for our gut cells and to support our immune system. Fibre can also help reduce cholesterol, keep us regular, and it helps regulate blood sugar 

 As the low FODMAP diet can lead to reduced intake of fibre, we are concerned about it potentially impacting the gut microbiome (a fancy term for the collection of bacteria that live in our gut!).  

There is a recent study that shows that individuals who had undergone the three-step low FODMAP diet had no significant difference in total bacterial abundance from baseline. In addition, the amount of bifidobacteria (a “good” bacteria in the gut) did not change significantly, however the production of short chain fatty acids did reduce slightly. 

This shows us the importance of not staying on the low FODMAP diet for life as low fibre intake long-term may negatively affect the gut.  

Why is it tough to get adequate fibre on the low FODMAP diet?  

Many foods high in fibre such as fruits, vegetables, whole grains, beans, lentils, and nuts are also high FODMAP. Unfortunately, I have seen many individuals who begin the low FODMAP diet neglect to sub in fibre containing foods for the high fibre foods they remove from their diet. 

Another common perception is that if you have IBS you should be on the low FODMAP diet for life. This is not the case! The whole purpose of the low FODMAP diet is for it to be a three-step process that identifies dietary triggers. Once triggers are identified many of the foods originally eliminated in the first step can be reintroduced. The three steps of the diet are as follows: 

1. Low FODMAP: all high FODMAP foods are eliminated from the diet (or servings are adjusted to low FODMAP servings). This is followed for 2-6 weeks until symptoms are controlled. 
2. Reintroduction: FODMAP groups are challenged systematically with a low FODMAP “washout” period between 
3. Personalization: diet is personalized based on tolerance of FODMAP groups 

It is super important to have a digestive health dietitian support you to ensure you are moving through the three stages and are not unnecessarily restricting your diet resulting in possible negative impacts to your gut health and nutrition.  

Ways to add in more fibre during the low FODMAP phase and beyond: High fiber low FODMAP foods 

How can you increase your fibre intake on a low FODMAP diet? Here are some high fibre, low FODMAP foods to consider while you are following the low FODMAP diet and beyond. 

Here are some examples of how you could put this together in a meal: 

• Baked Salmon, 3/4 cup quinoa, 3/4 cup roasted broccoli heads  
• Steak, 1/2 cup roasted sweet potato, tossed green salad (with low FODMAP dressing) 
• Cilantro Lime Chicken Power Bowl  
• Pulled Pork Burrito Bowl 

Additional Recommendations:  

Still looking for ways to bump up your fibre? Here are a few more practical suggestions: 

1. If you are constipated, try adding in two kiwis per day. The fibre in kiwi has high water holding capacity which helps with stool “bulking” as well as it contains an enzyme actinidin, which may help trigger you to go! 
2. Add in some super seeds! Add 1-2 tablespoons of ground flax or chia seeds to smoothies, oatmeal, yogurt, or sprinkle on top of cereal for a fibre boost. It has been shown to help constipation, abdominal pain, and bloating in some people with IBS. Here is a low FODMAP smoothie recipe you can add it to. 
3. Consider a fibre supplement: Although I always recommend diet strategies to bump up fibre first, sometimes a fibre supplement can be beneficial. A few options:

• Psyllium Fibre: generally tolerated by many people with IBS. It may be helpful in relieving constipation. It can sometimes lead to bloating, cramping, gas, and diarrhea in some individuals.  
• Partially Hydrolyzed Guar Gum: generally well tolerated by individuals with IBS. May provide benefit for both individuals struggling with IBS-C (constipation) and IBS-D (diarrhea). It may also help support our gut bacteria.  

Next Steps: 

IBS can be very complicated, uncomfortable, and confusing to manage.  If you are struggling with your digestive health and are feeling overwhelmed do not hesitate to reach out to work with one of our digestive health dietitians for support.