What Causes Constipation - 9 Root Causes to Consider

What Causes Constipation? (9 Root Causes to Consider from a Holistic Dietitian Perspective)

Many would agree constipation is a pain in the butt (in more ways than one… pun intended).  But in addition to interfering with your quality of life, constipation is also a sign that something is out of alignment with your health.  If you’ve been wondering what causes constipation, look no further!  

The goal of this article is to help shed light on what the heck is going on in your body, so you can start taking more aligned, informed action via a root-cause approach.

Disclaimer:  This article was written for general education purposes, not to replace medical or  nutrition advice from your healthcare team. Make sure you’re working with a doctor and a gut health dietitian nutritionist to receive custom advice tailored to your bio-individual needs!

What is constipation?

Constipation can mean a lot of things, and it exists on a spectrum.  But in a nutshell, to be “constipated” means you aren’t pooping enough, relative to what you’re eating.

Clinically, constipation is defined as a Type 1 or Type 2 on the Bristol Stool Chart. 

(See below for a visual reference, and feel free to learn more and download a free printable Bristol Stool Chart PDF here!)

The Bristol Stool Chart - Meaning and Interpretation - Whole-istic Living

In layman’s terms, being “constipated” could mean your poop is any or all of the following:

  • Small and incomplete (resembling playground pebbles or rocks)
  • Infrequent (less than 1x every 1-2 days)
  • Strained, painful, and difficult to pass
  • Impacted (too narrow and thin in diameter)

Regardless, constipation is no picnic! And it doesn’t happen for no reason. 

If you aren’t pooping enough, there’s always a reason behind it!

Root causes of constipation: Factors to consider

Your gut is very complex!  There are lots of possible reasons for why you’re not pooping enough.

Some reasons (like diet and lifestyle factors) are more simple and straight-forward to address than others (like medical conditions).

Either way, the root causes of your constipation matter, because they will help you and your treatment team to determine the interventions that will be safest and most helpful for you.

Here are some of the top underlying culprits of constipation, which I’ve witnessed in my private practice as well as in inpatient hospital settings:

  1. Diet
  2. Lifestyle
  3. Pregnancy
  4. Medication side effects
  5. Medical conditions
    • Hypothyroid 
    • Eating disorders
    • Methane-dominant small intestinal bacterial overgrowth (SIBO)
    • Inflammatory bowel disease
    • Mechanical blockage

what causes constipation - infographic with list of root causes

Let’s start with the most simple, and work our way up. 

(Note that this list of root causes isn’t exhaustive, since the topic of constipation extends far beyond the scope of a blog post! We cover root causes in greater depth in module 1 of my online program, the Complete Gut Repair Roadmap.)


I always recommend starting here.  Eating enough fiber and drinking enough fluids are fundamental for healthy digestion!

Here are a few questions to ask yourself if you’re unsure:

  • Am I eating a balanced diet with enough fiber (~20-25 grams/day for females, or 25-38 grams of fiber/day for males) mostly from fruits, veggies, and whole grains?
  • Am I staying hydrated and drinking enough water (~64 ounces/day)?

If you answered “no” and/or you’re unsure, you may benefit from the following resources:

Also keep in mind that when it comes to fiber, more isn’t always better.  Don’t exceed the recommended amount of fiber per day – or it could potentially worsen your gut issues!

The good news is that lots of people with mild constipation respond very well to these very simple interventions.  

(Many folks tend to overlook the foundational elements and hyper-focus on the bells and whistles when it comes to gut health, and health in general!)

More good news:  If your food choices and/or insufficient fluid intake were the only reason(s) for your constipation, you may actually not even need any “constipation tea” at all.

But unfortunately fiber and fluids aren’t always enough to kick your constipation to the curb!


Have you ever noticed that when you’re rushing in the morning, or when you’re traveling, your bowel movements are different (usually slower in many cases)? That’s not a coincidence!

Fundamental lifestyle factors like exercise/movement, sleep, and stress management fly under the radar when it comes to constipation.

These factors impact everything from our hormones and neurotransmitters (chemicals that affect how we think and feel) to our nervous system and gut motility in ways we can’t even fathom.

Some questions to consider:

  • Am I getting enough sleep (at least 7-8 hours, most nights)?
  • Am I staying active and getting enough (but not too much) exercise?
  • Am I managing stress?

If you answered “no” to any of those questions, or you’re unsure, you may benefit from looking into these fundamental lifestyle habits and checking out the following resources:

Note:  Adrenal fatigue isn’t a medical condition, but it’s something that shows up when you’re very stressed for long periods of time – and it’s a sub-type of stress-induced functional constipation.


If you’re expecting (congrats!) and you’ve noticed your bowel movements have slowed down lately, know that this is relatively normal!  This is because there’s a bit of extra constriction on the colon, for obvious reasons. 😉

Keep in mind, many herbal remedies for constipation (like laxative teas) are NOT safe during pregnancy. 

In cases of pregnancy-induced constipation, I still recommend making sure you address the lifestyle fundamentals (fiber, fluids, sleep, stress, movement) – in addition to consulting your healthcare providers individually.

Medication/supplement side effects

Many people are on some kind of medication, but aren’t aware that so many types of medication can lead to constipation as a side effect.  

(Weight loss drugs and diabetes medications are top-of-mind, as well as some psych meds!)

The medication side effects rabbit hole is beyond the scope of this article.  So we won’t go any further into it here.

Believe it or not, even certain dietary supplements (like iron supplements) can cause constipation! (Read more about the link between IBS and iron deficiency anemia here.)

But if you happen to be taking any medication and you’ve noticed a correlation, it may be worth looking at the list of side effects and consulting your doctor as needed.

Medical conditions

If you’re ruled out all of the above culprits, it’s possible that an underlying medical condition could be causing your constipation.

Below are a few of the most common medical conditions I see slowing down bowel movements in my functional gut health nutrition clinic.

  • Make sure you’re working with a doctor to help you figure this out via the right diagnostic testing!

Eating disorders

Did you know that there’s a link between IBS and eating disorders (especially anorexia and/or bulimia)?

How it works:  When we aren’t using our gut properly (i.e. stimulating digestive functions by eating enough and allowing food to pass all the way through the gastrointestinal tract), the gut will start to slow down and atrophy.

Think of it this way: when we don’t use it, we start to lose it!

(Read more about IBS and eating disorders here.)

If eating disorder behaviors are leading to constipation, it’s important to work with an eating disorder treatment team at the appropriate level of care (inpatient, residential, PHP, IOP, or outpatient).

My favorite U.S. based PHP, IOP, and outpatient eating disorder facilities are Behavioral Nutrition (I used to work there!) and Alsana, because of their holistic approaches.


The thyroid is a small butterfly-shaped organ located near the throat.  This small but powerful organ produces hormones which help regulate metabolism, as well as body temperature and – you guessed it – digestion!

When your thyroid isn’t making enough thyroid hormones, you can experience the following:

  • Fatigue
  • Weight gain
  • Hair loss
  • Constipation

Consider asking your doctor for a thyroid test, if you’re unsure whether or not this has been ruled out.  

Your doc will most likely check your thyroid stimulating hormone (TSH) first.

  • An optimal TSH level range should be between 0.75 to 2.5, by integrative and functional medicine standards. 
    • For context, the “normal” lab reference range you’ll see for TSH is computer-generated, based on the average of 98% of people who have gone to that lab in the last calendar year.  
      • This is not ideal and not the best point of reference! 

Always advocate for yourself, and NEVER assume your doctors are going to test you for “everything”.  That couldn’t be farther from the truth!  

In conventional medicine, sadly most doctors are overworked, burnt out, and they just don’t have the time or mental capacity to give you the full workup you truly need.  

Not to mention – they’re not always motivated or even taught how to pinpoint subclinical imbalances.

  • Consider working with a holistic, integrative, functional dietitian if you’d like to address subclinical thyroid imbalances.

If the underlying root cause of your constipation IS related to an underactive thyroid, you’ll need to rebalance your thyroid hormones either medically or via herbs (on top of eating enough fiber and drinking enough fluids).

But if you have the above symptoms and your thyroid is optimal, don’t get discouraged – it doesn’t mean you’re “fine” or that this is “all in your head”!  

…It means it may be time to investigate the possibility of microbial overgrowth.

Methane SIBO

“Methane SIBO” is a sub-type of small intestinal bacterial overgrowth (SIBO) which masquerades as constipation-predominant irritable bowel syndrome (IBS-C), since the symptoms are virtually identical to Hashimoto’s and IBS-C on the surface level. (1, 2)

What’s actually happening:  Methane-producing bacteria have migrated to your intestines, and they cause constipation indirectly.  

They do this by releasing toxins that induce an autoimmune-like attack on your Migrating Motor Complex (MMC)

  • The MMC is a branch of your gut’s enteric nervous system which helps regulate your gut motility.

The surface-level outcome of methane SIBO left unchecked is very slow gut motility… aka, horrible constipation. 

  • This constipation is also usually accompanied by lots of gas, bloating, fatigue, weight gain, FODMAP intolerances, and more!

While it may be tempting to just chug a bunch of laxative tea to help temper the discomfort of this evil microbe-induced constipation, I don’t recommend starting there!  (This approach is really no better than taking pills to manage symptoms.)

If you suspect OR have confirmed methane SIBO, make sure to work with a SIBO-informed doctor and dietitian, so you can eradicate the methane SIBO with the right herbal antimicrobials and/or pharmaceutical antibiotics (typically Xifaxan / Rifaximin).

Otherwise, keep reading!

Inflammatory bowel disease

Inflammatory bowel diseases (IBD) such as celiac disease, colitis, and Crohn’s disease stereotypically present as IBS-D, fiber/roughage intolerance, and chronic diarrhea.  

But this isn’t always the case!  (It all goes back to bio-individuality.)

Behind the scenes, in my private practice and even in my personal life, dozens and dozens of individuals have confided in me over the last decade, explaining how they were chronically constipated, gassy and bloated – and it turned out to be an atypical case of IBD.

(This is a conversation for another time, and something we cover more in-depth in the first few weeks of my Complete Gut Repair Roadmap online program.)

But in the meantime, I invite you to download a copy of my free gut health nutrition guide (5 common diet mistakes to avoid on your gut-healing journey) if you’d like to learn more!

Mechanical blockages

While we don’t really hear much about mechanical blockages in the gut, I was shocked at how often I used to see patients end up in hospital emergency rooms for this very reason!  

A few examples of mechanical blockages in the gut can include, but aren’t limited to:

Mechanical blockages are usually more acute, sudden-onset and severe.  They’re also often accompanied by nausea, vomiting and other issues.  

As you can probably guess, no amount of fiber, fluids, sleep, exercise, tea, herbs, or meditation will resolve a mechanical blockage in your bowel. 😉

Always see a doctor and even consider visiting a local emergency room / urgent care facility if your condition is severe and sudden-onset!

Related articles & resources

So, what causes constipation? (The bottom line)

There are many possible underlying factors that could be causing your constipation.  Generally I recommend starting with the simple stuff and working your way up to more complex stuff only as needed.

Look at your diet first, to make sure you’re eating enough fiber (from fruits, veggies, and whole grains) and drinking enough fluids, too.

Next, address lifestyle factors like sleep, exercise, and stress management.  (If you need extra support and accountability, consider working with a health coach to help you get on track faster!)

Pregnancy is another factor, and usually not a long-term issue (once baby is born!) but consult your medical team if fiber and fluids aren’t cutting it.

And of course, most types of medications come with unwanted side effects which I refer to as “collateral damage”. If constipation is a side effect of a medication or supplement you’re taking, set up a consultation with your doctor (and perhaps a dietitian, too) to determine the best way to address this.  

Once you’ve exhausted all of the above possible causes of constipation, if your issue hasn’t responded to any of those foundational interventions, there could be something else going on.

Eating disorders, hypothyroidism, methane SIBO, IBD, and bowel blockages are top-of-mind – but there are lots of other possibilities as well. Make sure you’re working with a doctor to help you get to the bottom of it – and advocate for yourself, as needed.

Nailing down the root causes of your gut issues  is something we actually take a few weeks to cover in my online program, the Complete Gut Repair Roadmap.

Next steps

There’s SO much more to say about constipation root causes & remedies! 

If you’d like to stay in touch and learn more, download my free gut health nutrition guide – 5 Biggest Diet Mistakes to Avoid When Healing Your Gut.

Free Download - 5 Diet Mistakes to Avoid When Healing Your Gut - by Jenna Volpe RDN LD CLT

Chat soon!
XO – Jenna

2 thoughts on “What Causes Constipation? (9 Root Causes to Consider from a Holistic Dietitian Perspective)”

    1. Jenna Volpe, RDN, LD, CLT

      Hi Olga, thank you for sharing. Yes, we’ve found psychosomatic factors like stress and trauma do make a big difference in gut motility from a stress/nervous system standpoint. We will make sure to add a section on this in the article! -Jenna

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