Various high fiber fruits and vegetables surrounding the word "fiber" written in chalk on a wooden board

Best High Fiber, Low Fodmap Foods to Avoid Constipation

Have you noticed a change in your bowel habits since starting the low fodmap diet? This is relatively common and likely due to not consuming enough fiber while following the diet.

Many high fodmap foods are also high-fiber foods. Examples include some whole grains like wheat and barley. Also, high fodmap fruits and vegetables are limited on the diet and these are also good sources of dietary fiber.  

If you are following the low fodmap diet, you may be wondering what you can eat to make sure you are getting enough fiber and having regular bowel movements. The good news is, there are many low fodmap options like quinoa, brown rice, allowed nuts and seeds as well as fruits like strawberries and vegetables like cucumber. For more ideas on how to get enough fiber while following the low fodmap diet, read on. 

Person standing in front of a toilet holding a toll of toilet paper

Fodmaps

For a quick background, fodmap stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. In short, they are fermentable carbohydrates.

The key here is that these types of carbohydrates are rapidly and easily fermented by our gut bacteria. This is the difference between fodmaps and other carbohydrates that are not as quickly fermented.

For some people with irritable bowel syndrome or other gastrointestinal conditions, this rapid fermentation process may cause symptoms of abdominal pain, gas, bloating and often loose stool. A diet low in fodmaps help to alleviate some of these symptoms.

An important side note to mention about the low fodmap diet: it is not necessarily meant to be followed long term. It is intended to be followed in it’s entirety for several weeks, followed by a challenge phase to determine which groups of fodmaps are most problematic.

At that point, you should liberalize your diet via the reintroduction phase to include fodmap groups that did not seem to trigger symptoms. It is best that you utilize the help of a Registered Dietitian trained in fodmaps to ensure you are getting a balanced diet throughout the process. 

Fiber

The recommended daily fiber intake is 14 grams per 1000 calories. So, this will be different for everyone but often this translates to somewhere between 20 and 35 grams per day. There are two different types of fiber and it is important to have a good understanding of these as we need a mixture of both in our diet. 

​Insoluble Fiber

This type of fiber is found in roughage foods like lettuce, fruit and vegetable seeds, skins or peels. It is also found in many whole grains. Insoluble fiber helps draw water into our intestines and can help regulate bowel movements. It does this by increasing stool transit time. This can be a very helpful type of fiber in the case of constipation.

Soluble Fiber

Soluble fiber, on the other hand, is found in foods like bananas, blueberries and oats. This type of fiber has a great water holding capacity and can actually somewhat slow transit time. This not only allows for more nutrient absorption but can also be very helpful if someone is struggling with loose stool. 

Note that many foods actually have some component of both soluble and insoluble fiber. However, there are foods that are quite a bit higher in one than the other and often categorized accordingly. 

How Can I Get Enough Fiber?

So how can we ensure that we are getting the proper amounts of both types of fiber while following the low fodmap diet? While the low fodmap diet does limit some fruits, vegetables, and grains, there are still plenty of options to choose from.

An important point to note is that VARIETY of these options goes a long way. Again, we need both types of fibers in our diet for optimal gut health. Eating as wide of a variety as possible within the low fodmap realm will help achieve this. 

High Fiber, Low Fodmap Grains and Starches

Here is a list of high fiber, low fodmap grains and starch options to include in your diet. 

  • Quinoa
  • Brown or wild rice
  • Whole grain pasta (from rice, quinoa, corn or a combination of these or other low fodmap grains)
  • Unpeeled potatoes 
  • Millet
  • Whole grain bread (from any low fodmap grain as long as the grain is “whole” or intact. You may also find low fodmap breads with whole seeds or whole low fodmap grains ADDED to the bread. This can be within the bread dough itself or sometimes sprinkled on top to increase its fiber content).
  • Corn 
  • Popcorn
  • Grits
  • Oat bran
  • Buckwheat (this does not come from the wheat plant and is low fodmap)
  • Puffed amaranth (1/4 cup)
  • Oatmeal (1/2 cup)

In addition to grains and starches, much of our intake of fiber comes from fruits. The flesh of the fruit itself contains fiber, but often, a large portion of the fiber component is within the seeds, peels and skins of the fruit. If possible, for increased fiber intake, choose fruits often that have these components.

High Fiber, Low Fodmap Fruits

Here is a list of high fiber, low fodmap fruits to include in your low fodmap diet. 

  • Strawberries
  • Blueberries
  • Kiwi
  • Raspberries
  • Pineapple
  • Firm banana
  • Dragon fruit
  • Cranberries
  • Passionfruit
  • Starfruit
A person holding a large handful of ripe strawberries in both of their hands

Do take note that all fruit does contain some fodmap component, even the low fodmap options. It’s best to limit fruit to small portions while following the low fodmap diet. Low fodmap serving sizes of fruit is generally about 1/2 cup. 

In addition to grains and fruit, another major source of dietary fiber is the vegetable group. Similar to fruit, the flesh of the vegetables themselves contain fiber as well as the seeds, peel and skins so leave these portions intake when possible. 

High Fiber, Low Fodmap Vegetables

Here is a list of high fiber, low fodmap vegetable options to include in your low fodmap diet. 

  • Leek (green part only)
  • Carrots
  • Lettuces such as kale, spinach, romaine
  • Collard greens
  • Bok Choy
  • Rhutabaga
  • Swiss chard
  • Green beans
  • Eggplant
  • Bell pepper   
  • Parsnip
  • Broccoli (<1/2 cup)
  • Butternut squash (<1/3 cup)
  • Cucumber, unpeeled

Other Low Fodmap, High Fiber Foods

Here are some other low fodmap foods that can help prevent constipation.

  • Flaxseed 
  • Chia seeds
  • Hemp seeds
  • Sunflower seeds

Also, allowed nuts can also be helpful in keeping bowels moving. Some good options include:

  • Walnuts
  • Pecans 
  • Peanuts 
  • Pine nuts
  • Macadamia nuts
  • Almonds (less than 10)

The above lists are not exhaustive, but certainly show that there are many high fiber, low fodmap foods that are safe to consume on the low fodmap diet. Incorporating a wide variety of these options can help prevent constipation and keep your digestive tract happy.

The key is to be intentional about how much fiber you are getting while following the diet. A good idea is to track or record your intake for a few days and tally up the grams of fiber.

This will allow you to get a “snap shot” of how you are doing fiber wise and if you need to step it up a bit. If you find that this is the case, read on to learn about a good option to fill in the gap if you are struggling to meet your requirements through diet.

Fiber Supplements

You can consider taking a low fodmap fiber supplement if you feel that you are not getting enough. See below for several low fodmap options.

These are all certified low fodmap (yes there is such a thing!) and so are safe to consume while following the low fodmap diet.

One last factor to note when it comes to constipation, is fluid intake. In may sound obvious but being intentional about staying adequately hydrated can make a huge difference in keeping “things” moving. So whether you are on the low fodmap diet or not, drink up!

For more on the specifics of the low fodmap diet, see related posts “What are Fodmaps?” and “3 Phases of the Low Fodmap Diet”.

As always, thanks for reading!