does intermittent fasting cause diarrhea

Does Intermittent Fasting Cause Diarrhea?

Written by Andrew Brewer. ⚕️Reviewed and fact checked by our medical team.

does intermittent fasting cause diarrhea

As you start your intermittent fasting journey, your body will undergo a series of changes. You’ll feel hungry, but your body will adjust to your new eating habits over time. In some cases, you may face indigestion, including bloating, gas, and diarrhea. It’s rare, but it does happen, so here’s what you can do if you get diarrhea during intermittent fasting.

Key Takeaways

  • Diarrhea can occur during intermittent fasting due to a variety of reasons, including consuming high-fat meals or too much caffeine, sweeteners, or electrolytes.
  • To prevent and treat diarrhea during intermittent fasting, it’s important to be mindful of what you eat and drink, consider adding probiotics and fiber to your diet, and avoid caffeine and other potential triggers.
  • While diarrhea is not a common side effect of intermittent fasting, persistent or severe diarrhea can lead to dehydration and nutrient deficiencies, which can have serious consequences. It’s important to seek medical attention if you experience severe or prolonged diarrhea during intermittent fasting.

What Causes Diarrhea during Intermittent Fasting?

Diarrhea can lead to dehydration, so you must address the problem quickly if you start to come down with it during intermittent fasting. You can get diarrhea when you break your fast or while you’re fasting for different reasons.

If you come down with diarrhea after eating, your body is likely reacting to the food you’ve chosen. High-fat meals can cause diarrhea because your body may not be able to digest them like it used to. Eating too much too fast can also trigger a response in your body to purge. Overall, it’s important to be aware of how you’re breaking your fast to prevent getting sick. You may feel like you’re starving, but your body needs time to readjust to the nutrients you’re feeding it after an intermittent fast.

If you’re feeling sick during a fast, consider what you are drinking. You may be drinking too much caffeine or using too many zero-calorie sweeteners. Even an excess of electrolytes can cause diarrhea during a fast, so it’s not always about what you’re eating that can cause your body to go out of whack. As you fast, your body is purging everything left in it, which may lead to diarrhea at first.

Overall, being mindful of what you’re eating and drinking during and after intermittent fasting can impact how your body reacts. If you feel sick, it’s important to drink a lot of water and fluids to prevent getting dehydrated. While a single bout of diarrhea is unlikely to cause health problems, long-term digestive issues can lead to more serious issues.

How to Treat Diarrhea During Intermittent Fasting

In addition to drinking a lot of water, you may want to consider adding probiotics to your diet. This can be through foods or supplements, and they can help restore balance to your stomach and GI tract by introducing more good bacteria into your system. Most probiotics have zero calories, so they won’t break your fast. Instead, they’ll help you start feeling better if you’re suffering from stomach issues like diarrhea, constipation, gas, and bloating.

Introducing more fiber can also help prevent diarrhea, helping food run more smoothly through your system. What you eat is just as important as when you eat, so increasing the protein, fiber, and healthy fats can lead to healthy bowel movements, while fatty, greasy, and oily foods can do the opposite.

Lastly, you may want to stay away from the caffeine, including coffee, tea, and energy drinks, even if they have zero calories, until you get your diarrhea under control. Excess caffeine and sweeteners can cause diarrhea if consumed too quickly during intermittent fasts because your body has nothing else to help soak it up.

Is Diarrhea a Guarantee During Intermittent Fasting?

No, diarrhea is not a common side effect of intermittent fasting. Instead, it’s likely a result of what you’re putting into your body during fasts and while eating. Be mindful of eating too much too fast after breaking your fast, integrating high fiber, protein-rich foods rather than fat-filled and greasy meals – no matter how much your body has been craving it! Doing so after an intermittent fast will only cause your body to go into shock, including developing diarrhea.

Don’t forget to check our recommended fasting apps to make your intermittent fasting journey easier.


  • Can intermittent fasting cause diarrhea?

In some cases, intermittent fasting can cause diarrhea as your digestive system adjusts to the changes in your eating patterns.

  • How does intermittent fasting cause diarrhea?

Intermittent fasting can cause diarrhea because it changes the balance of gut bacteria in your digestive system, which can lead to digestive issues like diarrhea.

  • Are there any other factors that can cause diarrhea during intermittent fasting?

Yes, other factors such as consuming too much caffeine or other diuretics during fasting periods, dehydration, and consuming high-fiber foods during eating periods can also cause diarrhea.

  • What can I do to prevent diarrhea while doing intermittent fasting?

You can prevent diarrhea by gradually easing into intermittent fasting, staying hydrated during fasting periods, avoiding diuretics and high-fiber foods, listening to your body, and adjusting your fasting schedule as needed.

  • When should I be concerned about diarrhea while doing intermittent fasting?

If you experience a severe or persistent diarrhea, it is important to seek medical attention as it may indicate a more serious underlying condition.

Andrew Brewer

Andrew Brewer

Andrew Brewer started to give people the guidance that he never received when he was first starting. His goal is to make your goals achievable and to offer you only the best fasting apps that the internet has to offer. You're not on your own - Andrew and the entire family of reviewers at are here with you every step of the way!