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Keto and IBS: 7 Reasons to Give the Ketogenic Diet a Shot

IBS is a painful digestive system disorder that involves diarrhea, constipation, or both. 

It’s the most common GI condition, but the causes aren’t entirely clear. However, plenty of people report relief after trying the keto diet.

Read on to learn what probably causes IBS, what you can do about it, and how the ketogenic diet may help.

What is IBS?

Irritable bowel syndrome (IBS) is no fun. The main symptoms of IBS are abdominal pain and discomfort paired with diarrhea or constipation, or all of the above. Other symptoms include bloating, cramping, and malabsorption of nutrients.

IBS affects up to 15% of people in first-world countries, and it affects women twice as often as men[*][*]. It’s now the most commonly diagnosed gastrointestinal condition[*].

There are four different categories for this diagnosis:

  • IBS-C refers to IBS where constipation is the most common symptom.
  • IBS-D means IBS where diarrhea is the main issue.
  • IBS-M is a mix of the two digestive issues (again, no fun).
  • IBS-U sufferers experience constipation and diarrhea rarely, meaning their main symptoms are pain and hypersensitivity.

Because it’s diagnosed according to symptoms rather than causes, not every case has the same origin. One person with IBS-D might have it for a different reason from another person with the same diagnosis.

What Causes IBS?

Medicine still hasn’t pinned down the exact cause (or causes) of irritable bowel syndrome. It’s only diagnosed in patients who don’t have obvious structural or biochemical problems that can be observed in their guts.

However, it’s not exactly a mystery syndrome. There are quite a few clues that point to patterns in IBS patients.

Studies show that gut bacteria are different in people with IBS[*]. That’s one reason the low-FODMAP diet reduces discomfort for up to 75% of people with IBS[*]. However, it’s not entirely clear whether the microbiome changes happen before or after IBS symptoms begin.

A more recent connection to IBS symptoms is the diagnosis of small intestinal bacterial overgrowth or SIBO[*]. SIBO is diagnosed when there’s an overgrowth of gut bacteria from your colon into your small intestines, and it can cause many of the same symptoms as IBS.

Another factor behind IBS is high stress levels. Often, people experience their first symptoms after a stressful life event[*]. And others have difficult childhood histories[*].

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Twice as many IBS sufferers struggle with anxiety compared to the general population[*]. Scientists also think that these changes in neurotransmitter levels can lead to a heightened sensitivity to pain, one of the hallmarks of irritable bowel syndrome[*].

Other research suggests that inflammation and autoimmune activity also play a role in IBS[*][*].

Basically, IBS is most likely a combination of bad gut bacteria, changes in pain response, chronic low-grade inflammation, and immune activation[*]. Any one or two of these factors may not result in symptoms, but put a few of them together, and you’ve got IBS waiting to happen.

7 Reasons The Keto Diet Might Help With IBS

Reports of the ketogenic diet easing or even reversing IBS symptoms are cropping up among doctors, diet websites, and even Reddit threads. 

Testimonials aren’t the same as hard data, but luckily there’s some solid evidence that helps explain why keto might be one way to obtain relief from IBS.

#1: The Keto Diet Changes Your Gut Bacteria

As we already covered, people with IBS have different gut bacteria. Doctors think these gut bacteria changes are a major factor behind IBS symptoms[*].

Some excellent research proves that keto can change your gut bacteria. Not only that, these microbiome changes are associated with relief from conditions like epilepsy and multiple sclerosis[*][*].

Keto results in a healthier microbiome, reducing bad bacteria and promoting beneficial strains[*]. Could these changes help IBS sufferers find relief, too? 

It turns out you don’t need to guess or rely on personal testimonies because a small study recently found out the answer is yes[*].

The patients were fed a very-low-carb diet with just 20 grams of carbs per day, which definitely fits the definition of the keto diet. During the four-week study period, all of the participants responded well, and 77% of them experienced full relief from going keto[*].

The researchers didn’t measure or address any microbiome changes, but based on other studies, it’s a safe bet that improvements in gut bacteria had something to do with the benefits.

#2: Keto is Wheat-Free

While people with IBS share common symptoms, not everyone has the same symptom triggers.

One such trigger is food intolerance, like wheat sensitivity. In these cases, scientists think gluten isn’t to blame — it’s probably other components in wheat[*].

The ketogenic diet eliminates grains, including wheat, so it’s an excellent choice if wheat is your IBS trigger. And just as importantly, going keto ensures you get plenty of nutritious whole foods to replace the empty calories you’re ditching.

#3: Low FODMAPs? Easy on Keto

FODMAPs are “Fermentable Oligo-, Di-, Mono-saccharides And Polyols.” Essentially, they’re different types of fermentable dietary fiber that feed your gut bacteria. 

Since IBS patients’ gut bacteria are out of balance, too much fiber can worsen the imbalance. That’s the reason a remarkable 75% of people with IBS get at least some relief from symptoms by following a low-FODMAP diet[*].

On the low-FODMAP diet, you reduce or eliminate the following high-FODMAP ingredients:

  • Inulin
  • Beet fiber
  • Corn fiber
  • Soy fiber
  • Citrus fiber
  • Carrageenan
  • Guar gum
  • Pectin
  • Cellulose
  • Sorbitol
  • Mannitol

In extreme cases, a low-FODMAP diet also eliminates whole foods like garlic, onion, bell pepper, apples, and avocado, to name a few. 

Because you avoid processed foods on keto and eat real foods that are high in protein and fat and lower in fermentable fibers, it’s easy to combine keto with a low FODMAPs approach to enjoy the many other benefits of keto.

#4: Low Chemical Diet? Also Easy on Keto

Although the majority of people with IBS respond well to reducing FODMAPs, it doesn’t work for everyone. In these cases, doctors think that chemicals from processed foods may trigger IBS symptoms[*].

Here’s what you need to watch out for if you suspect food additives are causing your IBS[*]:

  • Salicylates
  • Amines
  • MSG
  • Benzoates
  • Sulfites
  • Nitrites
  • Sorbic acid
  • Artificial colors
  • Artificial sweeteners

Additionally, some people may need to eliminate FODMAPs and the above food chemicals from their diets to get their IBS under control[*].

As with wheat and FODMAPs, going keto mostly eliminates these ingredients from your diet. However, it’s smart to consult a nutritionist or dietitian if you’re dealing with irritable bowel syndrome, because they can teach you to recognize all of these chemicals when you read food labels.

#5: The Keto Diet Reduces Inflammation (and Changes Your Neurotransmitters)

According to research, people with IBS have more inflammation than the average person[*]. These inflammatory changes relate to symptoms like increased sensitivity to pain[*]. 

Inflammation could also be one reason IBS patients are more likely to get Alzheimer’s and other forms of dementia[*][*].

High blood sugar is one cause of inflammation. When you eat a high-carb meal or snack, the resulting spike in blood glucose can lead to greater inflammation in your body[*].

However, by going keto, you can lower your blood sugar[*]. And when you’re in ketosis, your body also makes ketones like beta-hydroxybutyrate, which further reduce inflammation[*].

Anxiety, which is common in people with IBS, is also tied to inflammation[*]. The keto diet can change neurotransmitter levels related to stress and anxiety, which is another reason why it’s an excellent choice for IBS[*].

#6: More Short-Chain Fatty Acids

Short-chain fatty acids like butyrate, found in butter, are another useful way to lower inflammation in your gut[*]. 

You can pretty much eat as much grass-fed butter as you want on keto. It’s not just tasty — if you have IBS, it might help ease your symptoms[*].

In people without IBS, their microbiome converts dietary fiber into short-chain fatty acids (SCFAs) like butyrate. But studies show that if you have IBS, your SCFA levels are lower than average[*][*]. That’s another reason eating a high-fat diet can be a winning strategy to address IBS.

Not only that, butyrate actually works even better for gut health paired with beta-hydroxybutyrate (a ketone)[*]. To harness both of these compounds, eat a lot of grass-fed butter and go keto or low-carb and use a ketone supplement that contains BHB (or do both!).

#7: Keto Lowers Insulin Levels

You might already know that staying sensitive to insulin is essential for optimal performance, remaining slender, and preventing chronic diseases like cancer and heart disease. 

But did you know that lower insulin levels may also improve IBS symptoms? It’s true[*].

One 2016 study found that insulin resistance may be a piece of the IBS puzzle[*]. That’s because it’s associated with inflammation, and also because too much insulin can change your gut bacteria for the worse[*].

Luckily, the ketogenic diet is an incredibly efficient way to increase your insulin sensitivity[*]. Because insulin resistance is nearly always caused by eating too many carbs, keto is a no-brainer if you want to reverse this problem.

The Takeaway: The Keto Diet May Help With IBS Symptoms

The causes and symptoms of IBS are complex, but that doesn’t mean it’s impossible to find relief.

If you think you’re struggling with IBS but aren’t sure, talk to your doctor and ask for a referral to a gastroenterologist if needed. Other conditions like celiac disease, Crohn’s, and bowel obstruction have similar symptoms, so you need to be sure of the cause rather than self-diagnose.

Should you end up with an IBS diagnosis, a dietitian or nutritionist can also be a big help to implement a low-FODMAP diet or low-chemical approach. Scientific evidence strongly supports low-FODMAP and low-chemical diets for reducing symptoms. While these strategies don’t work for everyone, they’re definitely worth a try.

The keto diet is 100% compatible with both of these approaches. Not only that, but it also leads to better gut bacteria, reduced inflammation, production of beneficial ketones, healthy weight loss, and lower insulin levels. Win-win!

And if you feel like you’ve already tried everything with no luck, it’s probably time to give keto a shot, because lots of people with IBS report dramatic improvements on a low-carbohydrate diet.


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