What do I do if I get diarrhea on a ketogenic diet?

By Dr. Stephen Phinney and the Virta Team

There are three common errors made with a poorly-formulated low carbohydrate diet that can cause stomach and intestinal upset and diarrhea: sugar alcohols, too much protein, and the wrong source of dietary fats.

Diarrhea is not a common side effect of a well-formulated ketogenic diet. If it occurs, it likely due to well-intentioned but incorrect food choices. But while sorting this out, it is important that you stay hydrated and replenish your electrolytes!

It is also important to note that there are many causes of diarrhea independent of a ketogenic diet, so contact your doctor if your diarrhea causes severe symptoms or lasts longer than a week.

You may need to take a closer look at what you are eating.

Ask yourself a few questions:

1. Are you a frequent consumer of sugar free beverages, candies, protein/diet bars, and sugar substitutes? These can cause diarrhea.

Sugar free and low carb products frequently contain sugar alcohols to give them a sweet taste while avoiding table sugar (sucrose). These sugar alcohols (xylitol, sorbitol, mannitol, maltitol, lactitol, and isomalt) have been known to cause gastrointestinal distress (Makinen, 2016). Of these, sorbitol is the least tolerated, but all of them can cause gas, nausea, and diarrhea if consumed above one’s level of tolerance. Thus, eating fewer products containing sugar alcohols may help with your diarrhea.

This video explains the connection between sugar alcohols and gastrointestinal distress:

2. Are you eating low carb, low fat, and high protein? Too much protein can lead to diarrhea.

Remember, a well-formulated ketogenic diet is low carb, high fat, and moderate protein. When cutting carbs, it can be tempting to increase your protein without increasing your fat, but the resulting high protein diet can lead to diarrhea (Speth, 1983). It is important to keep protein at about 10-20% of your daily energy need and add ‘good fat’ for satiety. More on what constitutes ‘good fats’ below. Read more on how much protein you need on a ketogenic diet

3. Are you choosing the right sources of dietary fat? Some oils can cause diarrhea.

While a little bit of omega-6 and omega-3 essential fats are required from our diet, more is not better. In particular, our digestive systems have a limited tolerance for vegetable and seed oils high in omega-6 fats. Early in our human research, we found out that feeding our patients a high fat diet made with soybean, corn, safflower, or sunflower oils promptly made them feel nauseated and caused diarrhea. Given that a well-formulated ketogenic diet eaten to maintain body weight provides 70-80% of one’s daily energy intake as fat, the majority of this fat intake needs to come from mono-unsaturated and saturated sources such as olive oil, high oliec versions of safflower and sunflower, coconut oil, lard, butter, cream, and high fat cheese.

Here are some fats and oils that we recommend:

Keto diet - acceptable fats and oils

Citations:

Makinen KK. Gastrointestinal Disturbances Associated with the Consumption of Sugar Alcohols with Special Consideration of Xylitol: Scientific Review and Instructions for Dentists and Other Health-Care Professionals. Int J Dent. 2016; 2016: 5967907.

Speth JD, Spielmann KA. Energy source, protein metabolism, and hunter-gatherer subsistence strategies. J Anthropol Archaeol 1983; 2:1–31.

Back to Keto FAQ


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49 Comments

  1. Avatar

    I had some GI issues when I first started on the keto diet. It took a bit of trial and error, but I found that removing sugar alcohols cleared it up right away! Now I use stevia…worse taste but totally worth it!

    Reply

  2. Avatar

    My issue was too much MCT oil. Once I cut back on that, and gave up diet soda, my issues resolved.

    Reply

  3. Avatar

    This fats and oils chart is really helpful. I’ve been frying in sunflower oil, and I think I need to switch to canola or avocado to help my diarrhea issues.

    Reply

  4. Avatar

    I believe that sunflower oil and canola oil have too much omega 6, which is harmful.
    Only butter, ccoconut oil and extra virgin olive oil have the right profile among different fats. Tthe right fats are essential for us and keep us healthy.

    Reply

    1. Virta Health

      Check out our chart above! We have some other fats that are acceptable, such as beef fat and avocado oil.

      Reply

  5. Avatar

    I’ve been on a keto diet for 2.5 years to help control my diabetes. In the past couple of months i’ve started feeling nauseous after meals. I’ve also had several episodes of diarrhoea and vomiting, together and separately. I’ve started cutting out things that might be causing it e.g. sugar alcohols, maltodextrin. The problem is that even the idea of fat of any kind makes me nauseous. I wonder if anyone has any suggestions? My doctor has run blood tests & a stool test but nothing has come back positive so far.

    Reply

    1. Virta Health

      Hello Miriam! Im happy to hear you went to your doctor for testing. Those symptoms sound like the keto flu. Here are some articles that will help. https://blog.virtahealth.com/keto-flu-how-to-avoid-it/ and https://blog.virtahealth.com/vitamins-supplements-on-keto/ I hope that helps!

      Reply

      1. Avatar
        Mary Lee Stenstrom January 22, 2019 at 2:14 am

        Keto flu? After 2.5 years. No. Some other change? Aging, gall bladder? Something else

        Reply

    2. Avatar

      I have been on keto only 5 months and I find myself in a similar situation. No vomiting but definitely discomfortIn the gut and ( bloated belly ). Always after a meal. I am afraid to abandon keto but I need to figure out what is happening. Best of luck to you and I hope to follow your progress.

      Reply

    3. Avatar

      I started out eating three meals a day on my keto diet. After a couple weeks when my body got used to the diet, I too got sick to the smell of food. I decided to skip my meal. After that I started intermittent fasting and only eating one meal a day. I’m not sure if you can do that with your diabetes but it is worth looking into.

      Reply

    4. Avatar

      Have an endoscopy for sure to rule out an ulcer

      Reply

    5. Avatar

      I’ve only been on Keto diet for about 2-3 months and feeing exactly what you describe. Were you able to find out the problem?

      Reply

      1. Avatar

        I added vitamin d and it seems to help

        Reply

    6. Avatar

      That sounds like Gallbladder problems. A few people I have known who were on Keto had it aggravate their Gallbladders and they started vomiting. Took them a while to finally realize that is what it was, and had it removed.

      I doubt Keto gave them Gallbladder problems, just that it eventually exacerbated the situation.

      Reply

  6. Avatar

    I think the GI/diarrhea issues caused by different fats is not taken seriously by most. The MCT oil and bulletproof coffee trend has a lot of people suffering in the morning and not knowing why. Also, I remember Dr. Phinney telling a story about a study he was running where the participants were feeling absolutely gross and weren’t able to eat because of the oil used in the food he was serving (it was chicken or tuna salad made with low-quality mayo full of soybean oil with omega-6 if I remember right).

    Reply

  7. Avatar

    up your fiber and get on a probiotic for your gut -microbiome

    Reply

  8. Avatar

    Some times it can be a simple matter of good hand washing and cleaning the vegetables especially leafy greens in vinegar and water

    Reply

    1. Virta Health

      That’s a great point!

      Reply

  9. Avatar

    The only time that I have experienced diarrhea while living a ketogenic lifestyle has been due to a general sensitivity to sugar alcohols. As a result, I have to limit my intake of foods which contain these substances. Considering foods with sugar alcohols really shouldn’t be eaten in larger quantities/frequently anyway, this benefits my way of eating.

    Reply

    1. Virta Health

      Great point! It’s so important to recognize what foods are supporting us in our journey to better health and what foods may be holding us back from feeling our best.

      Reply

  10. Avatar

    Diarrhea is another possible side effect, especially during the first time on a low-carb diet, as your digestive system may need time to adapt to new way of eating. There are many steps to cure diarrhea, such as drinking plenty of fluids with electrolytes.

    Reply

  11. Avatar

    I’ve been on Keto for a month and have had direrreah the whole time. Is this normal?

    Reply

    1. Virta Health

      We aren’t able to provide direct medical advice through this channel. You may find our blog post on diarrhea helpful, though: https://blog.virtahealth.com/fix-diarrhea-keto/

      Reply

  12. Avatar

    I am tracking my intake and staying under 20% protein. I am only using Monk Fruit sweetener – so no sugar alcohol. & all of the fat in my diet has been cream, butter, lard and some Mayo. I am still experiencing diarrhea. Can I assume it is the mayonnaise? Would it help to switch to an olive oil mayo instead?

    Reply

    1. Virta Health

      I would compare the ingredients in your mayo to the ingredients listed in this post to see if you can identify any that may be problematic. There are some excellent mayos that are made with avocado oil that may be a good option for you.

      Reply

    2. Avatar

      Be sure to read labels. Even mayo listed as Olive Oil Mayo has been known to be largely soybean oil. I’ve found making my own (it did take a few attempt before I got it right) has made a big difference. I follow a very strict, clean eating keto and this has made a big difference to me.

      Reply

    3. Avatar

      I have been reading lots since I am a newly to keto and several people have said that they traced to to the monkfruit.

      Reply

  13. Avatar

    I have been eating all the right fats, my protein is always under %20 percent. The only thing from this list I can think would cause this for me is the sugar alcohol maybe? But I am consuming a lot less than I was off this diet. I’m having one diet coke a day and one serving of truvia in my coffee a day. Could that really be the cause? Or do I just need to adjust to the diet? Tomorrow will be my one week mark, I have to travel in about a week, I really don’t want to deal with this while traveling.

    Reply

    1. Virta Health

      It could be worth cutting out to see if it helps. Another trigger, for some people, can be an increase in dairy intake. If your dairy intake has increased significantly, you may want to cut back and see if that helps your symptoms improve.

      Reply

  14. Avatar
    Mary Lee Stenstrom January 22, 2019 at 2:15 am

    Keto flu? After 2.5 years. No. Some other change? Aging, gall bladder? Something else

    Reply

    1. Avatar

      Could be bile issues, fat malabsorption. Try one of the digestive enzymes ,HCL, lipase, pancrelipase, ox bile. Each is slightly different, but work towards the same end….helping digest fats better.

      Reply

  15. Avatar

    I bevive it is bacterial imbalance in your gut. The good bacteria in you gut feed of of glucose. When you go on keto the good bacteria goes down and bad goes up. If not corrected can cause leaky gut. To fix that start drinking bone broth will help repair the gut. And start eating fermented foods, like sauerkraut, kimchee, sour pickles. Also having some sea greens will help with both.

    Reply

    1. Avatar

      Hi Mike! Can you tell me which brand of sauerkraut you eat? I read it has to be unpasteurized.

      Reply

      1. Avatar

        Try Bubbies. It is an excellent line of fermented foods. The sauerkraut and kosher pickles are my “go to” for daily fermented snacks.

        Reply

      2. Avatar

        Bubbie’s Sauerkraut in the refrigerator section of your health food store. Its the best. Try the kosher picked too. these are some of my favorite fermented treats.

        Reply

  16. Avatar

    I’ve been low carb/dirty keto for almost a year, had some high fat intake related diarreah early on that cleared up. My dr ran a series of Zoomer tests recently and found a strong reaction to dairy. I backed off on dairy and within a week started having issues with upset stomach and diarrhea ever since. Maybe I should watch my percentages?

    Reply

  17. Avatar

    I need to change my “American” diet to something healthy. I’ve been told to try AIP (autoimmune paleo) because I have hyperthyroidism. My nephew and his wife do Keto and have had a lot of success with it. My hyperthyroidism already gives me issues with diarrhea so I’m wondering if switching to Keto/Paleo with the suggestions in this article would help me or if my autoimmune condition will make it harder to overcome this issue.

    Reply

    1. Virta Health

      It’s difficult to say how someone will respond to ketosis or if they will have issues with diarrhea. Many people do fine in nutritional ketosis and, if you follow the information in this blog, should help minimize an increase in loose stools.

      Reply

  18. Avatar

    Maybe too much magnesium supplementation or a form of magnesium that causes diarrhea…

    Reply

  19. Avatar

    I just started the keto diet and I am experiencing diarrhea all day … After I eat or drink what should I do

    Reply

    1. Virta Health

      I’m sorry but we aren’t able to provide specific medical advice via this forum. Please reach out to your healthcare provider to discuss.

      Reply

  20. Avatar
    Bridgett Braunscehidel April 10, 2019 at 3:01 am

    So I’ve been keto for a week and having diarrhea the last 2 days…thinking it’s the Propel I drink? Thought I was being proactive getting the electrolytes- didn’t realize I could also be getting sugar alcohols. Thoughts?

    Reply

    1. Virta Health

      That could definitely cause GI issues!

      Reply

    2. Avatar

      If you are worried about electrolytes, my suggestion is pickle juice. Yes, it’s a bit strong. At first, I had to dilute it 1/2 – 1/2. But it made a big difference in how I felt. Now, I can down an ounce or two as needed.

      Reply

  21. Avatar

    I can pretty much answer a very solid no to all of those questions and I still have diarrhea. My diet is super dialed in right now. I don’t touch fat bombs or MCT everything is from food not processed astronaut bs. It’s not like chronic diarrhea just loose….

    I am supplementing a lot of fiber because on lower carbs I tend toward Constipation. I guess I would rather have the train moving fast than not at all.

    Reply

  22. Avatar

    Hi is keto good for type 2 diabetic and diverticulitis as I suffer from both but my diverticulitis has been out of control lately even before I went onto keto but even on keto it’s still not any better any help or advice would be greatly appreciated

    Reply

    1. Virta Health

      Hi Will! We can’t provide specific medical advice, however ketones can help to block inflammation, which may be helpful in diverticulitis.

      Reply

  23. Avatar

    On the Keto diet for about 2yrs. About every 6 wks I would have a bile attack. I would vomit bile & diarrhea of bile. I finally stopped the diet & it cleared up. I was taking 1 tbs organic coconut oil, 1 tbs MCT oil, 3 times daily. I did lose 20 # , felt great but these bile attacks were terrible. Checked gallbladder, liver & pancreas, all fine. Cortisol & liver enzymes fine. I want to get back to keto diet but don’t want to go through the bile attacks. Am I doing something wrong or do I need to add something?

    Reply

    1. Virta Health

      Hi Bo! We can’t provide specific medical advice via this forum. However, some people have had success using bile salts and eating smaller, more frequent meals throughout the day. Dr. Phinney suggests consuming dietary fats mostly as emulsions (e.g., low polyunsaturated mayonnaise, cream, sour cream, Greek yogurt), and to spread the fat intake throughout the day rather than large amounts with any one meal on this post: https://blog.virtahealth.com/ketogenic-diet-no-gallbladder/

      Reply

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