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Constipation on a low FODMAP diet: 5 tips for smooth digestion

Constipation on a low FODMAP diet can be an unexpected challenge, especially if you’ve been suffering from the opposite issue. Fear not! In this blog, I’ll unveil 5 valuable tips to keep things moving and make your low FODMAP journey a breeze.

The restriction or elimination of high FODMAP foods, common triggers for gut symptoms, has been shown to help 2 out of 3 people who suffer from Irritable Bowel Syndrome (IBS). It seems to work particularly well for those who have IBS-D (as in Diarrhea). (1)

However, one side effect that some of us may experience while following this elimination diet is constipation. Are we destined to get rid of one unpleasant symptom only to develop another? Avoid this losing trade-off! Read on to learn why constipation happens and how to prevent it.

First, here is a quick review of what FODMAPs are and where they are found.

FODMAP facts

FODMAP stands for Fermentable, Oligo-, Di-, Mono-saccharides and Polyols. These are certain types of carbohydrates in foods that some of us don’t properly digest or absorb, leading to bothersome symptoms. Symptoms like gas, pain, bloating and diarrhea.

Commonly eaten high FODMAP foods include wheat, onions, garlic, apples, pears, beans and peas, and cow’s milk (with lactose).  An extensive list can be downloaded from the researchers who introduced the low FODMAP diet, Monash University in Australia.

Foods that do NOT contain FODMAPs (or are very low) include unprocessed meat, fish, poultry and eggs; vegetable oils; lactose free or non-dairy milk; potatoes and rice; grapes and oranges.

In the first phase of the low FODMAP diet, the diet restricts many high fiber foods, such as:

  • whole wheat
  • apples, pears, watermelon
  • asparagus, Brussels sprouts, cauliflower
  • beans and peas

Restricting these and other fiber-rich foods may lead to a low fiber intake and result in constipation. Let’s pause a moment to define constipation.

What is constipation?

According to the Mayo Clinic, constipation is passing fewer than 3 stools per week or having difficulty with bowel movements. Stools may be hard, dry or lumpy. (2) Chronic constipation is when symptoms last for 3 months or longer.

Common causes of constipation include the following:

  • A low-fiber diet
  • Deficient fluid intake
  • Sedentary lifestyle
  • Ignoring body signals for a bowel movement
  • Certain medical conditions, such as hypothyroidism
  • A side effect from a medication or supplement, such as pain medications or iron supplements
  • Sometimes no cause can be identified

Now, let’s review some diet and lifestyle tips to move things along if you experience constipation on a low FODMAP diet.

Tips for Relieving Constipation on a low FODMAP Diet

Below are five proven tips that have been shown to relieve constipation while following a low FODMAP eating plan. These tips will work for others too! Give one (or more) a try today.

Focus on low FODMAP fiber alternatives

It may surprise you to learn that there are plenty of good fiber sources on a low-FODMAP diet, even without wheat or beans!  However, it does take some planning and careful consideration.

Most Americans fall far short of the recommended fiber guidelines of 25-35 grams per day, and on a low FODMAP diet, it can be a greater challenge to meet this goal. To make it easier, plan to include a good fiber source with every meal, and boost your intake with fiber add-ins whenever possible.

Excellent sources of fiber on a low FODMAP diet include:

  • Ground flax seed: add 2-3 teaspoons to smoothies, muffins, oatmeal or lactose-free yogurt
  • Chia seeds: make chia seed pudding or add 1-2 teaspoons to smoothies or salads
  • Gluten-free oats: choose “gluten-free” to assure that the oats have no traces of wheat
  • Fruit: grapes, blueberries, oranges and kiwifruit**(see note below)
  • Vegetables: carrots, green beans, lettuce, spinach, sweet potatoes
  • Grains: brown rice, quinoa, popcorn
  • Fiber supplements: Psyllium husk or Partially Hydrolyzed Guar Gum (avoid added sweeteners like sugar alcohols)

**Recent research has shown that eating 2 kiwifruit per day is an effective treatment for constipation (3) and may have a natural laxative effect due to its unique composition.(4)

Prioritize Hydration

Adequate water intake is fundamental for a healthy digestive system, especially when following a low FODMAP diet. Water helps to soften stool, making it easier to pass. And fiber absorbs water, so its important to have adequate fluid to support an increase in fiber intake.

Individual needs will vary based on activity level, surrounding temperature, sweat loss, overall health, medications, and age. The U.S. National Academies of Sciences, Engineering, and Medicine has determined that an adequate daily fluid intake is:

  • About 15.5 cups of fluids a day for men (that’s 124 ounces)
  • About 11.5 cups of fluids a day for women (or 92 ounces)

If this daily guideline appears higher that what you’ve heard before, it may be because it includes fluids from water, other beverages and food. About 20% of daily fluid intake usually comes from food.

Try this delicious gut-healing smoothie recipe to help support your fluid needs and treat constipation too.

Stay Active

Engaging in regular physical activity plays a crucial role in promoting bowel regularity and alleviating constipation. Exercise stimulates the muscles in the gastrointestinal (GI) tract, promoting movement of stool through the intestines and reducing the time it takes to travel the distance.

There are several specific exercises recommended to ease constipation. Highlighted in this physician-reviewed article by Everyday Health, here are 4 types of exercise to try:

  • running
  • light cardio
  • core exercise
  • yoga

Not a runner? Walking or riding bike just enough to increase the heart rate may stimulate the GI tract. Aim for around 150 minutes of light cardio per week for consistent benefits.

Working core muscles helps strengthen abdominal contractions. Yoga helps the body tap into its parasympathetic nervous system, or “rest and digest” state, which may improve constipation.

Practice time-restricted eating

Eating only during certain time periods and fasting the rest of the time is called time-restricted eating.

How does can this practice help constipation? Restricting calorie intake between meals or fasting overnight causes the body to turn up its migrating motor complex (MMC). The job of the MMC is to propel undigested food through the digestive system. It’s like a housekeeper, sweeping food and bacteria along so it doesn’t take up residence.

Because the MMC works best during periods of fasting, many health experts recommend the following:

  • Allow at least 3-4 hours between meals or snacks
  • Do not eat overnight (or during your sleeping hours)
  • Fast for at least 8-12 hours, mostly during sleep times

This relatively easy tip can help those suffering from sluggish digestion or constipation fairly quickly.

Consider your supplements and medications

It may surprise you to learn that medications and supplements may also cause or worsen constipation.

Many medications may have this side effect. Some classes of these medications include strong pain relievers, non-steroidal anti-inflammatory drugs, antidepressants, antacids containing calcium, and some blood pressure medications.(5) Check with your healthcare provider or pharmacist if you have questions.

There are several over-the-counter or prescription medications used to treat IBS with constipation. To learn more, check out this article from Verywell Health.

The most common supplements associated with constipation side effects are iron and calcium. This is often due to their formulation, such as iron sulfate and calcium carbonate. Gentler on the stomach and with fewer side effects are iron bisglycinate and calcium citrate.   

Supplements shown to help improve constipation include:

  • Betaine HCL
  • Digestive enzymes
  • Magnesium
  • Vitamin C
  • Some types of probiotics

It’s important when deciding to take a supplement that you discuss your particular needs with your healthcare provider. What works for one person may not work for another, and it’s not a good idea to take more than you need.


Managing constipation on a low FODMAP diet is achievable with a thoughtful and balanced approach. By prioritizing hydration, fiber-rich foods, physical activity, timing of eating, and appropriate supplements, smooth digestion can be maintained even while following a low FODMAP lifestyle.

Remember, everybody is unique and adjustments may need to be made to suit the individual. Interested in a personalized plan? Contact me for a complimentary discovery call today.

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