Gas and bloating: The causes and how to stop it

Most of us are familiar with the unpleasant feeling of being bloated. It can happen after we eat specific foods or have slower bowel movements. And sometimes, it can be a symptom of an underlying health condition. 

To take a closer look at issues related to gas and bloating, we’ve invited a special guest this week: superstar gastroenterologist and ZOE’s U.S. Medical Director Will Bulsiewicz.

In today’s short episode of ZOE Science & Nutrition, Jonathan and Will ask: What are the main causes of gas bloating, and how do we stop it?

Follow ZOE on Instagram.

If you want to uncover the right foods for your body, head to and get 10% off your personalized nutrition program. 

Studies referenced in today's episode:

  • Burden of gastrointestinal symptoms in the United States: Results of a nationally representative survey of over 71,000 Americans.

  • Abdominal bloating is the most bothersome symptom in irritable bowel syndrome with constipation (IBS-C): A large population-based internet survey in Japan.

  • Sensation of bloating and visible abdominal distension in patients with irritable bowel syndrome.

This podcast was produced by Fascinate Productions


[00:00:00] Jonathan Wolf: Hello and welcome to ZOE Shorts, the bite-sized podcast where we discuss one topic around Science and Nutrition. I'm Jonathan Wolf. And this week we have a new expert joining me. Will Bulsiewicz is a board-certified gastroenterologist, author of multiple New York Times bestselling books on gut health, and ZOE's U.S. medical director. 

And before this podcast, I looked up gastroenterologist to understand what it meant. And the dictionary defines this as a medical practitioner, qualified to diagnose and treat disorders of the stomach and intestines. And since today's subject is gas and bloating, it seems like will you are the perfect person for the job! 

[00:00:49] Will Bulsiewicz: It's great to be here today. I'm super excited to talk about this topic. It's an important topic issue related to gas and bloating are incredibly common. One in six of us will experience bloating, but the symptoms that lead to bloating are far more complex than we often give them credit for.  

[00:01:04] Jonathan Wolf: Thanks Will, and I have children. So I know that this is often a subject of much entertainment for my kids, but it's also a very serious topic. So this week we're gonna try and find out what it is that's causing gas and bloating.  

[00:01:15] Will Bulsiewicz: I think there's some pretty great research that explains why we experience bloating. 

And we may even have some ideas about how to combat it.  

[00:01:21] Jonathan Wolf: Sounds good to me. 

So when it comes to gas and bloating, we did some research and it's one of the most common problems that people report. So about one in five people in the United States report experiencing bloating. And it probably goes further than that.

So, I think anecdotally, a lot of people will get dressed in the morning and by the afternoon, their belt may feel a little tighter or their jeans are maybe uncomfortable around the waist. And that feeling of being bloated is incredibly common. Even if we're not going to see a doctor about it. 

[00:02:04] Will Bulsiewicz: It is. Bloating is the feeling of increased abdominal pressure, usually related to gas. And while for some people, this bloating is visible. Like they almost can look like they're pregnant. Others will feel the discomfort of bloating while displaying minimal or no distension of their stomach.  

[00:02:20] Jonathan Wolf: And Will, I think a lot of people attribute bloating to days when they've had like a big lunch or perhaps this idea that their body is just producing excess amounts of gas because of something they ate is that what's going on. 

[00:02:33] Will Bulsiewicz: What's happening with your body is a bit more complicated. That's the thing that people need to understand. If we want to get better at managing the bloating issue. We have to understand the nuance that's what's gonna allow us to get there.  

[00:02:44] Jonathan Wolf: So you're saying there's quite a lot of different things that might be going on that explain why I might be suffering from it.  

[00:02:49] Will Bulsiewicz: Exactly. In fact, I would say there are four main causes of bloating that are worth discussing. The first is swallowed air. Second constipation. The third is a struggling microbiome, gut microbiome, specifically. And then the last is our food choices.  

[00:03:03] Jonathan Wolf: Well, why don't we start at the beginning with the swallowed air? So I can think of many ways that air can get into the body, but, I think we should probably start with the most obvious way, which is through the mouth.  

[00:03:13] Will Bulsiewicz: Yeah. I think the most obvious way for air to get into your body is the air that's being swallowed. So any air that enters your body through your mouth is ultimately gonna have to be expelled one way or the other. So you can belch it out up top, or it has to wiggle its way through your intestines to come out the other side, as you pass gas from below.  

[00:03:32] Jonathan Wolf: So that makes sense. And the air we breathe in, you know, has to go somewhere. We did some research on this and there's a condition called aerophagia, which occurs when a person swallows too much air it's quite common and can be displayed through things like frequent gulping. Many people won't even realize that they're doing this air swallowing and it's the cause of their discomfort. If they suffer from regular bloating.  

[00:03:54] Will Bulsiewicz: Absolutely. These people suffer from intractable belching as well. They're the person who can belch their way through the ABCs you've ever seen a teenage kid do that. The air that comes out when you belch is the air that entered at some point when you swallowed.

So that is not air being produced by your gut microbes or something like that. This is the reason why it doesn't smell nearly as bad, but other common sources of swallowed air that people need to be aware of include carbonated drinks, sipping through straws, chewing gums, and sucking on hard candies. 

And then also some people, they swallow air when they eat. So they're aggressive eaters, they eat fast, they drink fast, they do big gulps and the air enters their body when they do that. So, you know, the bottom line is that if the air gets in. Has to come out one way or the other, and it may work its way through the 20 to 25 feet, the six to eight meters of intestines before it comes out your bottom on the other end, which can be extremely uncomfortable. 

[00:04:55] Jonathan Wolf: So if we're discussing entrances and exits, you know, I think naturally we should talk about the other end and talk about the bowels. How do they relate to gas and bloating?  

[00:05:03] Will Bulsiewicz: Yeah, we need to talk about this. So the bowels are actually extremely important to this type of manifestation of gas and bloating, specifically in people that have slow bowel movements,  

[00:05:14] Jonathan Wolf: Which otherwise is known as constipation. 

[00:05:17] Will Bulsiewicz: This can lead to intestinal gas, retention, symptoms of bloating, and abdominal discomfort. In my experience as a gastroenterologist, the number one cause of gas and bloating that I've seen is constipation. And in people who are constipated, the most common symptom that they experience is gas and bloating. 

[00:05:37] Jonathan Wolf: So these two are very sort of tied together Will.  

[00:05:40] Will Bulsiewicz: Yeah, they're very much intertwined. And you know, we have research Jonathan showing that people who are constipated, produce more bowel gas. So I think it's worth noting that people with irritable bowel syndrome and chronic constipation may experience difficulties with regard to gas and bloating and these challenges that exist. 

It can come from many different sources which could include difficulty relaxing their bottom. Difficulty having a good, complete evacuation or bowel movement, no matter what it is. If you're suffering from constipation. There's a high likelihood that you're gonna be suffering from gas and bloating at the same time. 

[00:06:18] Jonathan Wolf: So in these cases, if you can remedy the constipation, you can hopefully offset some of the unpleasant side effects of bloating.  

[00:06:24] Will Bulsiewicz: Yeah. That's actually what I typically will strive to do as a gastroenterologist from my perspective, I want to get them into a rhythm and get their bowels more regular. And if you can accomplish that, what I typically have seen is that the gas and bloating goes away.

[00:06:37] Jonathan Wolf: Got it. And so I guess fiber also can fit into this, right? So fiber can hold onto water. Can soften stool, you know, a high fiber diet, in general, is correlated with quicker transit times of food, generally helping people with more regular bowel movements.  

[00:06:53] Will Bulsiewicz: Uh, yes, but. There's a bit of a caveat. So, I mean, I am the world's biggest fan of fiber, but I also believe in keeping it real. 

And you know, the thing you have to understand is that people who have mild constipation will generally improve when they increase their fiber intake.

And oftentimes they can do little things, like take a walk through their neighborhood, or have a few glasses of water, all that gets them there. But the people who have more moderate or severe constipation, the people that are suffering with sort of a daily challenge when it comes to constipation. 

These people actually may find that fiber makes their constipation worse. So my approach to this situation, it's not to say that fiber is bad. It's more so to say that I like to focus on getting their bowels moving first, and then I will ramp up the fiber second. So move the bowels first. And then the fiber helps to maintain the bowel rhythm. Once you've done that.  

[00:07:45] Jonathan Wolf: Speaking of fiber, you know, and gut health. What about the role of our gut microbiome? So we've got these trillions of bacteria munching away on our food. Presumably, that's gonna generate a lot of gas.  

[00:07:56] Will Bulsiewicz: Yeah. So our gut microbiome plays an important role in processing and digesting our food. 

And this is. Particularly true with high-fiber foods. So when the gut microbiome is impaired or injured, it may struggle to process and digest when this happens. This is when you can experience side effects like gas and bloating.  

[00:08:16] Jonathan Wolf: So Will, we've discussed a lot about our bodies, but what about the things we eat? How do external factors like the food we choose lead to gas and bloating? ,  

[00:08:26] Will Bulsiewicz: This is a part of the equation. You know, certain foods are more common in terms of producing gas and bloating. So we need to be aware of those.  

[00:08:35] Jonathan Wolf: And from your experience, Will, what would you think are the two biggest areas of concern? If somebody is experiencing chronic gas and bloating and listening to this. 

[00:08:43] Will Bulsiewicz: I have advice that I routinely would give to people who come in with gas and bloating, like literally on the first visit. And that would be to eliminate non-fermented dairy and artificial sweeteners.  

[00:08:58] Jonathan Wolf: Fascinating. We just did an episode about artificial sweeteners and we're probably gonna do some more in the future. So can we start with those?  

[00:09:04] Will Bulsiewicz: Yeah. People have traditionally thought of artificial sweeteners as being benign. I mean, I've certainly been guilty of this myself. 10 years ago. I was dropping a couple of packets of Splenda into every single coffee.  

[00:09:14] Jonathan Wolf: That's a lot of sweeteners  

[00:09:16] Will Bulsiewicz: Yeah. Yeah. And I've moved on. I drank my coffee black now, I've gotten used to it. But the thing is they're not absorbed by the intestinal system. They don't contain calories and for these reasons, people think of them as just being completely benign, but actually, it's a lot more complicated than that.

They still come into contact with our gut microbes. And because they're coming into contact with our gut microbes, they can be fermented or they can have different effects on our digestive system that ultimately cause gas and bloating also people should be aware they can cause diarrhea. 

[00:09:44] Jonathan Wolf: So that makes sense on sweeteners. What about dairy? Why would you look to eliminate that?  

[00:09:49] Will Bulsiewicz: Well, I think, first of all, Jonathan, let me sort of making a distinction. There are dairy products that are fermented, and then there are dairy products that are not fermented and fermented dairy products are things like hard cheeses, kefir, or yogurt. 

And the fermentation process is unique because the microbes, the bacteria that are living as a part of the ferment, consume the lactose.  

[00:10:13] Jonathan Wolf: And Will, could you just, what is lactose?  

[00:10:16] Will Bulsiewicz: Lactose is a sugar. So it's the rare example where an animal product, you know, in this case, dairy, actually contains a carbohydrate. 

So lactose is a sugar that is specifically found in cow milk. Around 70% of the world is intolerant to lactose. So what that means is that, I mean, there's a certain amount that they can tolerate. It's not an allergy, but when they exceed what their body is capable of consuming.

Then the digestive symptoms kick in, and they get gas and bloating. And once again, somewhere to the artificial sweeteners, they may get diarrhea. So, you know, for these people, if they were to lower their intake of these lactose-containing dairy foods, they would find their digestive symptoms would improve very quickly. 

[00:11:15] Jonathan Wolf: Brilliant. So there we have it, it turns out like so much on this podcast that gas and bloating is a lot more complex than just having tight trousers and that there are a lot of reasons why you might experience it. So when we sum this all up, Will, if somebody is experiencing gas and bloating, What steps do you think they should take to remedy the situation? Help us to pull it all together. 

[00:11:36] Will Bulsiewicz: I think for the person who's at home, what I really want to encourage you to do is to think about these four specific things because it could be a combination of them. So do a personal intake. If you're suffering from gas and bloating, do you sip through straws? Chew gum, drink, carbonated drinks, and eat fast. 

Do you have constipation? Do you eat foods that are known to cause a lot of gas and bloating? And the last thing is, is there any sort of history of irritable bowel syndrome or damage to the microbiome? This will help you to sort of getting closer to what's going on. And then once you understand that, then you can create plans that are more targeted in terms of your approach. 

[00:12:16] Jonathan Wolf: And Will, I find I do experience some bloating and gas sometimes, particularly when I'm ramping up some new food that Zoe thinks is great for me, but has lots of fiber in it. Do I just need to avoid that food?  

[00:12:29] Will Bulsiewicz: No. So the answer is not to avoid. We don't wanna avoid what we want we want to include that food, but we also wanna understand that our body may take time to adapt to it. 

So if you haven't been eating that food in the past, then you're just not ready to consume large quantities of it, but you absolutely could be in the future. So you just start low and you go slow and over time by increasing the amount and giving your body a chance to adapt to what you're doing. You're gonna find that you're able to tolerate it. 

[00:12:56] Jonathan Wolf: So there you have it. I think some fantastic advice, including don't exclude start small and build up because diversity, I think is what you and so many other experts are talking about. We can't promise to remove gas or bloating at Zoe, but if you'd like to understand more about your own gut bacteria and how to improve your overall health, you can certainly try Zoe's personalized nutrition program and get 10% off by going to join

I'm Jonathan Wolf  

[00:13:23] Will Bulsiewicz: And I'm Will Bulsiewicz.  

[00:13:29] Jonathan Wolf: Join us next week for another ZOE podcast.