One of the hardest side-effects to mitigate on the keto diet is the potential for diarrhea.
We all have heard about how Jenna Jameson or Halle Berry have achieved their dream bodies using the keto diet...
But, the one thing that these stories never mention is the unwanted adverse event that often comes with starting a high fat diet - upset stomach.
The surprising side-effect that isn't so uncommon after all.
This is a way how your body is adjusting to your new lifestyle, burning fat for energy.
There are various reasons why your body can react with diarrhea: from fat intake to supplementation.
In this article, we give you 4 exact tips on how you can calm down the firehouse and start enjoying the ketogenic journey again.
Does keto really cause diarrhea?
You either have just started your ketogenic journey or you have been enjoying high-fat lifestyle for months now, and all of the sudden your stomach starts blowing up and wants you to officially move into the bathroom.
This is can be very uncomfortable and scary. And you may start wondering if this is what ketosis really looks and feels like? Not quite.
When you change your diet so drastically, as keto does, you don't only change your food but also your gut flora or microbiome (bacteria). (1)
It's normal to experience a period of digestive tract issues like diarrhea, while you dramatically have raised the fat intake and cut out all the carbs from your menu.
Common causes of diarrhea
In general, there are 3 main reasons why you may be experiencing diarrhea during the keto diet: increased fat/MCT intake, sugar alcohols, and excessive magnesium supplementation.
- Increased fat/ MCT intake - This is probably the first and the most common reason why your body is experiencing sudden diarrhea. It's your body’s way to adjust to the high-fat content that you have started to eat. This is especially true if you are taking added fats like MCT oil or coconut oil (2). These products are known to be the source of diarrhea by their own, if taken too much too sudden. Your gut isn't used to it yet. Your body is using bile to break down fats. So, if you increase fat intake, your body needs to make more bile which is also a lubricant for the colon. And since your colon is more lubricated, well, you get the picture. 
- Sugar alcohols - The keto approach is focused on high fats and focusing on reducing the amount of carbs eaten from the menu. With carbs, you will remove everything sweet from your diet, because well, at the end of the day all sweets are very high carb. Sugar is also the easiest way to kick yourself out of ketosis, no matter how much or how little you consume. The only choices you have left with are sugar-free and low-carb products, which most are pumped up with sugar alcohols which give them the sweet sweet heavenly taste. The most popular sugar alcohols are xylitol, sorbitol, mannitol, maltitol, lactitol, and isomalt. They have also known to be causing gastrointestinal distress.
All of these can cause gas, nausea, and diarrhea if consumed more than your body can tolerate. Simple conclusion, the less you eat sugar alcohols, the better it will help your diarrhea. Most sugar alcohols don't stimulate insulin release in the body. One reason for that is that half of these sugar alcohols are not properly absorbed through the digestive tract. The more you eat them the more symptoms it will cause in your GI tract.(2,3)
- Magnesium supplementation - This is the main reason why many experience diarrhea during keto at first. It has nothing to do with the keto diet itself, rather the supplementation of magnesium i. Supplementing with Magnesium Citrate irritates the bowels and induces diarrhea. Diarrhea, abdominal cramps and bloating are common side effects of exceeding the suggested daily quantity of magnesium supplementation. (4)
- Other - There can be other reasons why you are experiencing diarrhea, which has nothing to do with the ketogenic diet. For example, you may be experiencing food allergies, SIBO (small intestinal bacterial overgrowth), food intolerance or something completely else.
Is diarrhea a keto-flu symptom?
Well, not exactly.
While yes, diarrhea can be one of the side-effects of the keto flu, in addition to fatigue, decreased appetite, headaches, nausea and brain fog (5)
But the keto-flu typically disappears during a couple of weeks (if you follow the recommendations - focus on increasing your electrolytes (sodium, potassium, magnesium, calcium) and do not cheat. (6)
This happens because your body is transitioning to the fat burning mode and is getting used to the new metabolism of using nutrients. (7)
After the transitioning phase, usually, the keto-flu related diarrhea symptom will fade.
Any time you drastically change your diet, your GI tract will most likely to react.This will happen when you follow either a raw or high-fiber diet as well. This is due to the changes in your microbiome, that help us metabolize our food. (8)
So, what it comes down to is what are your circumstances. If you are experiencing diarrhea during the keto flu process, then yes, it is a side effect.
If you have already been in ketosis for a long time and suddenly experience GI issues, then the reason can be somewhere else.
Maybe you have cheated and your body is reacting?
Maybe you have strained your body with too much MCT at once?
Or maybe your body does not digest certain foods well. You may have a food intolerance. (9)
How long does it last?
If your GI upset is related to the keto diet or the keto flu, with good preparation, you can avoid this or help decrease your side effects. Usually after the transition period when your body adapts to using fat as fuel, the unwanted side effects subside.
After that, your body should have been effectively been transitioned to ketosis and will be running on fat.
If your diarrhea persists after the keto-flu then this is a clear sign that the problem is somewhere else.
There can be many reasons for simple food intolerance to allergies or something else.
You can try the elimination diet to rule out some specific food. (10)
If you are still having issues, then contact your Doctor or Registered Dietitian.
How to treat it?
Now you know all the potential reasons why you are experiencing keto diarrhea. There are only a few ways to combat diarrhea while sticking to a strict keto diet.
You can find relief by adding certain foods, or supplements toyour diet as well as removing some supplements you are currently taking and foods eaten.
When you eliminate certain problem foods, it can be more effective than adding other foods or supplements to the diet.
What to take
- Soluble Fiber - This would be in the form of a supplement as it is difficult to get this kind of fiber in the diet (it is mainly found in white rice, bananas, and potatoes for instance.) It is recommended to trial benefiber or metamucil, both derivatives of psyllium husk, which can add more bulk to your stool. It is important to only consume 1 serving of the fiber in only 2 ounces of water instead of the recommended 8 oz of water. This will help you have less loose stools. You can also find soluble fiber in foods like chia seeds and flaxseeds. (11)
» Check out organic Psyllium Husk here
- Decreasing fiber in your diet - Avoid eating raw vegetables if you are experiencing diarrhea. Cook all vegetables and avoid raw salads. When you cook your foods, you decrease the insoluble fiber content of the foods, which is what increases your GI transit time. (12)
- Probiotic rich foods - These are a good way to restore your digestive tract health. First, we would suggest eating probiotic foods that contain live and active bacterial cultures. The side-benefit comes thanks to the fermentation process which makes it easier to digest. Some examples of probiotic foods are sauerkraut, probiotic yogurt , kefir cheese and pickles. They are awesome at helping your gut bacteria grow. If probiotic foods are not just your game, then you can also check out probiotic supplements. (13)
» Check out natural probiotics here
What to stop doing
- Magnesium Citrate supplements - If you are supplementing with magnesium citrate, then it may be beneficial to put that supplement on pause until your diarrhea has subsided. This is because it draws additional water into the colon (14)
- Coconut oil products (incl. MCTs) - Coconut oil is rich in MCTs which are digested really fast and used for energy. Adding MCTs to your diet will help to reach and maintain ketosis, but because they are so rapidly digested, it can also cause abdominal cramps and diarrhea. This is especially true if you have just started taking MCT supplements. During the diarrhea phase, ease up on the MCTs and MCT rich foods to take the load of your body. When you are feeling like million bucks, then SLOWLY add them back into your diet. (15)
- Certain vegetables - Another big reason is that your body is probably not used to digesting the number of leafy greens and other veggies. Some vegetables can be harder on your belly than others. Consider cutting down on onion, garlic, artichokes, leeks, brussels sprouts, cabbage, and cauliflower. Prefer lettuce, cucumber, tomato, bean sprouts, bell pepper, and zucchini. Once you feel better, try bringing these foods back on your menu. (12)
If any of the above didn't work for you then it may be related to allergies or food intolerances. The best way is to do an allergy test and try an elimination diet that removes common allergens and intolerances from your menu. Some of them are for example wheat, eggs, fish, dairy, nuts, peanuts, soy, some veggies, and shellfish.
If you are seeing positive changes then start adding foods back to your diet one by one. Monitor how you feel and how your body reacts. If you suddenly feel any reactions to these foods, then chances are that you have either allergy or food intolerance.
If anything didn't work, then there maybe is time to look at the truth and consider that maybe the keto diet is just not for you. As you already know, the best diet and best results will come from a diet that you feel comfortable sticking into while not experiencing daily firehouse on the toilet.
Alex is the founder of Bodyketosis, an author, low-carb enthusiast, and a recovering chubby guy who reclaimed his health using the ketogenic lifestyle. The need for the keto life began after his aunt and cousin were diagnosed with type 2 diabetes and he was next in line. Through personal experience and extensive scientific research, Alex offers insightful tips for everything keto.