12 Common Causes of Bloating (and How to Eliminate Them)

X Common Causes of Bloating FinalWe’ve all been through it. You come home after a big day at the dog park, your owner pours a few cups of meaty kibble, and in your zest you can’t help but inhale the food. You chase it with a bowl-full of ice water. Sated, you try to lie down under the dining room table, but you can’t get comfortable. No position feels right. There’s something pressing on your insides. You feel like vomiting, but nothing comes out. Several dry retches later and the reality of the situation hits you: bloat. On goes the leash and you’re off to the emergency vet for a quick intervention.

Oh, wait. That’s not right. Sorry, I warged into my goldendoodle for a second. Bloat kills dogs. In humans, bloating isn’t fatal. But it is unpleasant, unattractive, and uncomfortable. It’s also difficult to pin down because it’s so nebulous. Let’s try anyway.

Bloating can manifest in a number of ways:


Distended stomach.

Tight belts.

Gut pain.

Feeling “puffy.”

Bloating is mostly subjective. You can “feel” bloated without experiencing actual stomach bulging. Other times, it adds actual inches to your waistline.

Why does it happen? Why do our stomachs distend and our sphincters proclaim their gaseous intentions to the world? What causes this nebulous condition and how can we avoid and fix it?


FODMAPS, aka fermentable oligosaccharides, disaccharides, monosaccharides and polyols, are short-chain carbohydrates that are supposed to be absorbed in the small intestine and utilized by the body. In most people, that’s what happens: they get digested and absorbed. In the unlucky people who have trouble digesting them, FODMAPs make it to the colon for fermentation by gut bacteria. And that’s where the trouble starts. Fermentation begets hydrogen gas, which gathers in the gut and causes great distress. Common complaints of the FODMAP intolerant are bloating, stomach pain, and visits to the toilet that are either unproductive or way too productive.

For more information on low-FODMAP diets and avoiding the most common and immediate cuases of bloating, check out Fruit Belly. It’s a great primer for avoiding bloat, particularly the kind caused by maldigestion of short-chain carbohydrates. Also see my previous post on FODMAPs for the full list of foods that contain them.

Remember the FODMAPs as you read the rest of the post. You’ll notice the FODMAPs showing up throughout this article. When it comes to bloating, they are very often involved.

See my post for ideas on how to fix your FODMAP intolerance. Because never being able to eat Brussels sprouts, garlic, onions, and stone fruit is a terrible fate.

2. Stress

Psychological stress inhibits the action of GLUT2, the transporter responsible for the small intestinal absorption of glucose, fructose, and galactose in the gut. Without GLUT2, we can’t absorb those carbs, and they’re more likely to pass through to the colon for fermentation and gas production. Stress also alters the composition and function of your gut flora, making your gut bacteria less diverse and opening up space for certain gas-producing pathogenic species to overpopulate.

Get a handle on your stress however you can. Meditation (or its alternatives), herbs and teas, anti-stress strategies, frequent nature infusions, a daily walk. Rethink it. Just do it.

3. IBS

Among IBS patients with constipation, bloating is the symptom that receives the most vociferous complaints. It seems that IBS patients have trouble getting rid of the gas they accumulate. The gas literally cannot be expelled.

Try GAPS (Gut and Psychology Syndrome) diet or SCD (specific carbohydrate diet). Finding a good health practitioner may also be important.

4. Obesity

Obesity is consistently associated with bloating. It may not be causal, exactly. Whatever causes obesity may also cause bloating. But if that’s true, fixing the obesity will likely fix the bloating, too. Plus, who wants to be obese anyway? It’s bad for your health.

Lowish-carb Primal is my preferred solution for obesity. It really gets the ball rolling and it seems to be the easiest path to follow. I’m biased, of course.

5. Wheat

Several studies identify gluten/wheat as a major bloating culprit. In Mexican adults, those who reported adverse reactions to gluten had objectively higher rates of bloating and constipation. Both the gluten itself and the short-chain carbohydrates found in wheat may pose gastrointestinal problems for susceptible people. Among some subjects, the non-gluten FODMAP components may even be the primary offenders.

Don’t eat wheat, rye, or barley.

6. Small intestinal bacterial overgrowth (SIBO)

In SIBO, the normally depopulated small intestine is overrun with bacteria. More gut bacteria should be awesome, right? Not in the small intestine. SIBO is characterized by a reduction in lactase (the enzyme that degrades lactose) and poor absorption of sorbitol (a polyol) and fructose (a monosaccharide). This allows all three short-chain carbs to pass through to the colon for unwanted fermentation and gas production.

As with IBS, a well-established protocol like GAPS (Gut and Psychology Syndrome) diet or SCD (specific carbohydrate diet) may also help against SIBO. In the meantime, try a low-FODMAP diet to eliminate the offending carbohydrates.

7. Imbalanced gut bacteria

Some gut bacteria consume carbohydrates and produce methane. Some consume them and produce hydrogen. Still others consume the gases other bacteria produce. If you have a lot of the gas-producing bacteria and few of the gas-consuming bacteria, you’re asking for bloating.

Fix your gut bacteria. I know, I know: that’s no easy feat. But I’ve written extensively on the subject, so revisit those posts for some ideas. As bacterial sequencing is still kinda spotty, use your symptoms as a guide for tracking the effectiveness of your interventions. Good thing is that feedback is fast.

8. Constipation

The inability to “go” is a potent cause of bloating. I’d argue that it’s even worse than gaseous bloating because solid things are just sitting there. They aren’t moving, they’re accumulating. And as long as you’re eating and digesting, more is always arriving. This creates a terrible bloat. A heavy bloat. A physical bloat that can’t be relieved with a few well-placed farts or burps.

Most people with chronic constipation report bloating.

Check your fiber intake. Both too much and too little can cause constipation. Explore resistant starch, prebiotics, probiotics, and fermented food. Fermented dairy (yogurt, kefir) may be of assistance.

9. Low stomach acid

Without adequate stomach acid, alkaline bacteria who’d normally be unable to establish themselves are suddenly free to set up shop. If you recall what I wrote several paragraphs back about SIBO, you’ll know that this leads to poor carbohydrate digestion and successful delivery of fermentable short-chain carbs to the colon for gas production.

Stomach acid also promotes the secretion of carb-digesting enzymes in the intestines. If stomach acid is low, those enzymes run low, too, and it’s harder to digest carbohydrates. More carbs make it through for colonic fermentation (and gas production) in the context of low stomach acid.

It could be said that bloating causes GERD, as the presence of gas in the gut can distend the stomach and exert sufficient pressure to push its acidic contents up into the esophagus.

Betaine HCL can restore stomach acidification in certain conditions. Apple cider vinegar (a couple tablespoons mixed in a cup of water) can also help here. Going low-carb, thereby reducing the amount of carbs available for fermentation, has also been shown to improve symptoms of GERD.

10. Eating and drinking too quickly

For the same reason gulping kibble can cause bloat in dogs, eating your food too quickly can cause bloating in humans: it increases the likelihood of swallowing air.

Slow down, chew your food more, take smaller bites. Don’t eat kibble.

11. A full stomach

Eating a massive meal is a great way to feel bloated. I mean, you’ve literally filled your GI tract with food.

Eat smaller meals. Eat till satiated, not until you hate yourself. If you’ve eaten a large meal, take a walk.

12. Creatine

Creatine is one of those supplements with few downsides. It just works (unless it doesn’t). But part of the reason it works can also cause perceived bloating. Creatine promotes increased intracellular water storage, or water retention. As this water isn’t available for body-wide thermal regulation—it “sticks around”—and can give the impression that you’re bloated. The evidence is quite mixed on this one, but the preponderance of anecdotes from people complaining about “creatine bloat” makes me think there’s something going on. Even if it doesn’t show up on objective tests, if you think you’re bloated, you might as well be.

Stick with it. Creatine takes some getting used to. Most “creatine bloating” is due to the increased water retention being a new sensation.

What did I miss, folks? What are the common triggers for bloating in you? How do you deal with them?

Thanks for reading, everyone!

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About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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34 thoughts on “12 Common Causes of Bloating (and How to Eliminate Them)”

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  1. I’m still digesting that you have a goldendoodle. I imagined a wolf-dog mix.

    However, this makes sense in that from what I’ve read, your ultimate goal is not 100% adherence to staying in the primal box, but using the primal method to achieve a happy and healthy life. In Malibu, a goldendoodle is really a great fit.

    1. Goldendoodles are super primal!
      The sprints alone…
      If only I could teach mine to actually catch the deer that wander through my backyard… dinner is served!

      1. Mine can catch rabbits on the fly. He big 75lbs but super agile. When he had a lion cut, nobody could recognize the breed so I invented one. South Island Wookie, “They’re bred in New Zealand specifically to catch rabbits.” He’s older and leaves rabbits be but still not the typical doodle. Now he’s a Laguna Filpflop Retriever. He consistently greets guests at the door with a flipflop in his mouth.

  2. I had never heard about creatine bloat. I’ve had my own experiences of bloating/indigestion with other supplements though, particularly acidic ones like alpha lipoic acid. Sometimes buffering them other foods helps.

  3. I have used creatine twice before, and both times I got notably stronger, and yes, more bloated. One of the side effects not commonly discussed about creatine is its capacity to elevate blood pressure. Both times, my BP (particularly my systolic) crept up over time. As high BP is the most significant marker for early mortality (above all others) I ditched it. Sure was fun to see the strength gains though…

  4. Oh, FODMAPS. I actually consume a good deal of vegetable juice for this reason: I get the vitamins/nutrients without the fiber overload. I’m not talking V8. I’m talking broccoli, spinach, kale, and other low glycemic veggies straight into a Breville or industrial juicer. I don’t make it my life like a raw foodie, but it’s a nice little pick-me-up and nutritional boost without all the fermentable solids.

  5. I had never heard of the acronym SIBO before. When I think of gas/bloating, I think of an imbalance of intestinal bacteria. But I never thought about how the disproportionate overgrowth in one area of the intestines or the other could have a different effect. Makes sense though.

  6. With the exception of Creatine, can I say I have issues with every single thing listed? Not a happy camper.

  7. I’ve heard of betaine hcl before and thought about recommending it to friends with GERD. Glad you reminded me about it, Mark!

  8. Onions. I don’t have any problems if I mostly avoid them. Life without onions isn’t the end of the world.

  9. I have a lot of bloating (water retention) when I am dealing with estrogen dominance!

    1. I’m surprised not to see that (estrogen dominance) on the list. After several years of being Paleo/Primal and not seeing any improvement in many issues including phenomenal bloating, I’ve been looking into the hormonal track and it’s been revolutionary for me. Many years of estrogen dominance will have decreased thyroid hormone effectiveness (causing hypothyroid symptoms with “normal” thyroid labs) which decreases digestive activity, causing bloating and nutrient malabsorption, and will have likely reduced gallbladder effectiveness which is another reason unto itself for bloating (which I also wish had been on this list). Estrogen dominance is a buggerbear which I haven’t seen addressed enough in the Primal community, considering the havoc it’s wrought in my life and so many others I’m aware of. The man who coined the term (estrogen dominance) – John R. Lee, MD – wrote several books any one of which is well worth reading. My personal go-to: What Your Doctor May Not Tell You About Menopause. Primal compatible. Modern (xenoestrogenic) world necessity. The Mr is reading ‘Hormone Balance For Men’ and blown away by the ah-ha finds.

  10. One of the first benefits I saw after going paleo-primal was reduction in bloating.

    It’s also one of the first benefits many of my clients report when transitioning to primal eating. For a handful of them, a key issue is hypo-acidity of the stomach due to or made worse by raw juices, smoothies and too much water around meals. Another key issue is the effect of wheat and grains. Once they give those two things up, so much shifts…including the bloat.

    1. This is true; certainly for me and others I’ve talked to.

      You feel lighter in the middle, between the lower ribs and the base of your abdomen. It’s almost like there’s a hole there where there used to be a permanent feeling of fullness and heaviness.

  11. For me it’s wheat (and grains in general). With everything else I’m pretty good. Back in my vegan days I always felt bloated, even though I weighed considerably less than I do now. I just ate Brussels sprouts and cherries at the same meal and feel great. So don’t think FODMAPS are a problem. Thankful for that!!!

  12. Where does Einkhorn wheat fit into the picture? It supposedly is quite different from regular wheat in its chromosomal make up and in its lack of hybridization. Though, it does contain gluten. Also, how bout quinoa..is this a reasonably healthy substitute for wheat? Thanks

  13. Great info, thanks!

    Any chance you’ll be doing a similar article on fluid retention? I seem to get fluid retention just by breathing… I’ve yet to find any helpful articles out there on the interweb.


  14. Thank you so much for this post! I was diagnosed with IBS in college and just tried to ‘hide’ my symptoms. I still had some gut issues but am realizing it may be due to eating store bought yogurt for my snacks or in-betweens. In fact, I’ve been making a concerted effort towards clean/primal eating the past few days and couldn’t figure out why I was experiencing discomfort. I think I now know the source! Love Marks Daily Apple and am reading the Primal Blueprint every day. Nice to know there are options and solutions out there.

  15. You forgot the female POV again.
    Hormonal/cycle related bloating.
    Also, especially after multiple babies, the abdominal muscles give up and boom! – Diastasis: the appearance, at least, of bloating.

    1. Yes, I can relate to that! And also being an older, post-menopausal female.

    2. Add pelvic congestion syndrome, which is basically internal varicose veins. Extremely treatable, but so hard to diagnose because it isn’t easy to see.

      Along with the bloating there can be pain varying from mild to intense, and that feeling of fullness or heaviness…

  16. Another cause is gastritis. Excessive consumption of alcohol or NSAIDs, or H. pylori infection, can compromise the gastric mucosal lining. This allows stomach acid to react with the stomach wall, damaging it and producing gas. Note that in this case, taking HCl supplements will aggravate the problem.

  17. My bloating is the worst when I drink a protein shake after a hard crossfit workout. Tried different brands of whey, beef or paleo and some are worse than others but they all give me a swollen looking abdomen.

    1. I had this problem for a bit. Pea protein seemed to work best for me. Adding a tiny bit of fat while drinking it (a couple cashews is my go to) helps too. And not drinking it too fast!

    2. If they have stevia in them, protein shakes ALWAYS bloat me. Irritating to no end that everyone rushed to add stevia to their formulas. I have almost entirely given up protein shakes now. My post workout go to is salt free tunafish now, or flank steak (but slow digestion with the red meat creates a food baby 🙁 )

  18. I have this problem for 12 months now. It varies from slight discomfort to 6 month pregnant but I can’t get rid of it. The only thing that works is not eating anything, but that’s good on the long run. I tried everything. The only thing that happened is that the list of things I can’t eat gets bigger and bigger. I can’t eat cruciferous vegetables, I can’t eat any grain, I can’t eat any nuts, I can’t eat plantain. The list goes on and on. Curiously, I never had this issue before going primal.

    1. Yep! Me too! Trying different approaches but have not figured it out yet. Don’t think I had the bloat problem before I started eliminating all these foods WTF? So tempted to go back to the old way of eating just to see.

      1. Same here .. it’s been 5 years since your original comment, have you find something that works ? Or did you return to eating the old way ?

  19. After dropping almost 70 pounds eating mostly primal/omni, I stopped having many bouts of heartburn and bloat. My go-to now is ginger kombucha when I have that feeling; that drink has made my gut feel monumentally better, even better than after the weight loss.

  20. Not to split hairs, but bloat itself won’t necessarily kill a dog on it’s own….the torsion (the stomach twisting) is what can do them in in a matter of minutes. Of course, if the dry heaving and restlessness happens, get to a vet yesterday because you’ve got a very limited amount of time, and many cases of bloat happen because the torsion happens and then the dog is in big, big trouble. Keep those deep-chested breeds quiet before and after a meal, and keep them from tanking up on water if you serve dry, processed food.

    Dogs, designer mixes or not, are primal enough and many will naturally rest after a big meal. My Shepherds are always kept quiet an hour before and after eating, even though they eat PMR. My older Shepherds will lie down and chill, but the youngsters have to pretty much be crated or hog-tied to keep from wanting to wrestle and do crazy things right after a big meal.

  21. I get the bloat whenever I eat grains, like being stuck at an event where it would be insulting or make a scene to lose the bread. My best reset is prebiotic potato salad as follows: Boiled and cooled red potatoes with skins, chopped chives or green onions, crumbled bacon and cooking grease(because bacon is awesome), then mash it all together and moisten with liquid whey from plain yogurt and/or apple cider vinegar. This together with probiotic capsules and/or lactofermented veggies works great.

  22. I realise that it’s not a common cause of of bloating, but post-menopausal women who have new onset bloating should really see their doctor as it can be a sign of something sinister like ovarian cancer.