3 Surprising (but Common) Reasons You Might Be Bloated, According to a Dietitian

While some belly bloating is normal, like during your period and after eating a very large meal, other times, it's not normal. If you've been feeling bloated lately, one of these three things might be to blame. Here's what you can do to help fix your bloat.

In my twelve years working as a dietitian in gastroenterology practices, I've met more bloated bellies than I can count. I even wrote an entire book, The Bloated Belly Whisperer, about all the different medical reasons that someone might experience chronic bloating. These reasons range from slow-to-empty stomachs to acid indigestion to carbohydrate malabsorption, celiac disease, and small intestinal bacterial overgrowth (SIBO).

But beyond the medical reasons for a bloated belly, certain behavioral habits can also contribute to significant gas, bloating, and distension—even among healthy people without an actual digestive disease or condition. Here are three of the more common ones I encounter:

Your Healthy, (Excessively) High-fiber Diet

My patients prone to constipation (rightly) believe that fiber is the key to regularity, and regular pooping is the key to preventing bloating. As a result, they tend to eat the maximum amount of fiber in all scenarios. Why have regular pasta when you can have chickpea flour pasta? Why not add extra seeds and nuts to that giant kale salad? How about replacing those pita chips for peppers and carrots with that pre-dinner hummus snack?

These plant-rich, fiber-forward choices ensure my patients have a great bowel movement every day, so they can't figure out why they still wind up super bloated every single night after dinner, no matter what they eat.

Here's the issue. Fiber, by definition, is indigestible. This means that all fiber going in has to come out. If you eat, say, 40 grams of fiber each day but only manage to poop out half that amount in terms of the fibrous residue. Then, what's leftover starts building up day, after day, after day. Chronically eating more fiber than your body gets the urge to eliminate can lead to a substantial—pardon the expression—"backlog."

That backlog typically expresses itself in the form of nightly bloating, distension, and flatulence. Many of my patients who fall into this category are shocked to learn that they're technically "constipated," as they are often able to have easy, sizeable, normal-looking bowel movements each day!

If you suspect this may be the issue, your doctor can order an x-ray to visualize your "stool burden" to confirm the diagnosis. When 'backed up bloating' is the cause of your symptoms, a gentle laxative regimen at bedtime to help you poop out more volume the following day is often helpful. Work with your doctor to figure out how to add a laxative, like magnesium or Miralax, to your routine in a safe and gentle way and also how to wean off of it.

In tandem, I suggest my patients lay off large amounts of roughage for a few weeks while tinkering with their laxative regimen to help the body "catch up" on its pooping. After all, we don't want to replace every gram of fiber out with two grams of fiber in!

Think of foods that are a little easier to digest like puréed soups instead of salads, nut butter instead of nuts, and a few dinners with white rice instead of nightly grain and veggie bowls.

Swallowing Too Much Air

Is your bloating characterized by constant, incessant, and loud belching? Did it get worse when you started working from home and found yourself talking non-stop on Zoom calls all day long? Or maybe it seemed to ramp up along with your allergies when your nasal congestion and post-nasal drip flared?

Does the belching and gas hit you whether or not you've eaten, and seem not to correlate at all to specific food choices?

If any of this sounds familiar, you may be experiencing aerophagia, which is Latin for "air swallowing." Air is full of nitrogen gas, and when it's swallowed into our digestive tract, it has only two options to exit: to be burped out or farted out.

There are many scenarios in which you might unknowingly swallow air, including gum chewing, smoking, chugging water, gulping for breath during vigorous exercise, mouth breathing—when awake or asleep—talking for long periods of time or while eating, extra swallowing due to post nasal drip, or simply as a subconscious nervous habit when feeling stressed or anxious.

There is no silver bullet dietary remedy for bloating from aerophagia unless you can identify that you are swallowing air when eating or drinking specifically. If that's the case, drinking from a straw can help, as can tucking your chin to your chest a bit before swallowing a mouthful of food.

An over-the-counter medicine, called simethicone, taken every few hours throughout the day can be helpful to reduce the gas pressure associated with swallowed air. Depending on the circumstances under which you are swallowing air, working with a gastrointestinal (GI) doctor, allergist, or psychiatrist to address the underlying cause is generally the best long-term solution.

Your Probiotic Supplement

Many people use probiotics hoping to optimize their gut health or manage bothersome digestive symptoms. Some report experiencing significant improvements in their digestive symptoms when they luck into a particular probiotic strain that is well matched to their condition. But the flip side can also be true: it's not uncommon for probiotic supplements to actually worsen symptoms of gas and bloating.

Indeed, a small 2018 study validates what I've seen often in my own clinical practice: in some cases, probiotics can aggravate gas, bloating, abdominal pain, and even some associated symptoms like "brain fog." The researchers found a substantial number of participants with these symptoms also had an underlying condition called small intestinal bacterial overgrowth (SIBO).

Furthermore, they hypothesized that the probiotic supplementation might even cause SIBO in participants who had low stomach acid due to the use of acid-suppressing medication (proton pump inhibitors, or "PPIs") or who had slow gastrointestinal motility. Participants who did not have SIBO were told to stop taking their probiotics and those who had SIBO were treated with antibiotics and told to discontinue their probiotics; 70% of the group had their gastrointestinal symptoms substantially improved following these interventions.

It makes sense. Living bacteria ferment fiber, sugar, and carbohydrates to feed themselves, and the byproduct of this fermentation is gas. Supplementing pills with concentrated doses of live, probiotic bacteria certainly does raise the possibility that these organisms could kick up the amount of gas in your gut once they're released from their capsule coating.

If you're a longtime probiotic user who is experiencing worsening gas, bloating, distension, brain fog, or other symptoms, it may not be a bad idea to take a break for a few weeks and see if things improve.