Why Do I Get Diarrhea After Intermittent Fasting?

Intermittent fasting has become a popular trend for weight loss and overall health. However, some people experience uncomfortable side effects such as diarrhea. Understanding why this happens can help individuals adjust their fasting routine and avoid this unpleasant symptom.

Diarrhea after intermittent fasting can be caused by a variety of factors including changes in gut microbiota, dehydration, and the body’s reaction to certain foods. By identifying the root cause of this issue, individuals can make informed decisions about their fasting routine and ensure a more comfortable and successful experience.

Intermittent fasting can cause diarrhea as your body adjusts to the changes in your eating patterns. Fasting can affect your gut bacteria and cause an increase in bile production, which can lead to diarrhea. To prevent diarrhea, start with shorter fasting periods and gradually increase the duration. Make sure to stay hydrated and eat plenty of fiber-rich foods during your eating windows.

Why Do I Get Diarrhea After Intermittent Fasting?

Why do I get diarrhea after intermittent fasting?

Intermittent fasting has become increasingly popular as a weight loss strategy. However, some people experience diarrhea after fasting. In this article, we will explore the reasons why this happens and what you can do to prevent it.

What is intermittent fasting?

Intermittent fasting is a dietary pattern that involves restricting food intake for certain periods. There are different types of intermittent fasting, but the most common ones are the 16/8 method, where you fast for 16 hours and eat during an 8-hour window, and the 5:2 method, where you eat normally for 5 days and restrict your calorie intake to 500-600 calories for 2 days.

Benefits of intermittent fasting

Intermittent fasting has been linked to several health benefits, such as weight loss, improved insulin sensitivity, reduced inflammation, and improved brain function. However, it is not suitable for everyone, especially pregnant or breastfeeding women, people with a history of eating disorders, and those with certain medical conditions.

Why does intermittent fasting cause diarrhea?

Diarrhea is a common side effect of intermittent fasting, and there are several reasons why this happens. One of the most common reasons is that fasting can disrupt the balance of gut bacteria, leading to diarrhea and other digestive issues.

Another reason is that fasting can cause changes in the secretion of digestive enzymes and hormones, which can affect the absorption of nutrients and lead to diarrhea.

VS: Constipation

On the other hand, some people may experience constipation after intermittent fasting. This is because the lack of food can slow down the digestive system, leading to constipation. To avoid this, it is important to drink plenty of water and consume fiber-rich foods during the eating window.

How to prevent diarrhea during intermittent fasting

If you are experiencing diarrhea after intermittent fasting, there are several things you can do to prevent it. Firstly, make sure you are drinking enough water during the fasting period to stay hydrated. Secondly, try to consume foods that are easy to digest during the eating window, such as lean protein, fruits, and vegetables. Avoid foods that are high in fat or fiber, as they can trigger diarrhea.

Benefits of staying hydrated

Staying hydrated during intermittent fasting has several benefits, such as reducing hunger, improving digestion, and preventing constipation. Aim to drink at least 8 glasses of water per day, and more if you are exercising or in a hot climate.

When to see a doctor

If you are experiencing severe or persistent diarrhea after intermittent fasting, it is important to see a doctor. This could be a sign of an underlying medical condition, such as inflammatory bowel disease or celiac disease.

Table: Foods to avoid and foods to consume during intermittent fasting

Foods to avoid Foods to consume
High-fat foods Lean protein
High-fiber foods Fruits
Spicy foods Vegetables
Caffeine Water

In conclusion, diarrhea is a common side effect of intermittent fasting, but it can be prevented by staying hydrated, consuming easy-to-digest foods, and avoiding triggers such as high-fat or high-fiber foods. If you are experiencing severe or persistent diarrhea, it is important to see a doctor to rule out any underlying medical conditions.

Frequently Asked Questions

Intermittent fasting is a popular way of losing weight, but it can sometimes lead to digestive issues such as diarrhea. Here are some possible reasons why this may occur:

What Causes Diarrhea During Intermittent Fasting?

Diarrhea can occur during intermittent fasting due to various reasons such as:

1. Rapid changes in the diet: When you start intermittent fasting, your body may not be used to the sudden changes in your eating pattern. This can cause your digestive system to react and lead to diarrhea.

2. Dehydration: Fasting can cause dehydration, which can lead to diarrhea. It is important to stay hydrated during fasting periods to avoid this.

How Can I Prevent Diarrhea During Intermittent Fasting?

To prevent diarrhea during intermittent fasting, you can:

1. Gradually introduce fasting: Start with shorter fasting periods and gradually increase the duration as your body gets used to it.

2. Stay hydrated: Drink plenty of water and other fluids during fasting periods to avoid dehydration.

Can Certain Foods Trigger Diarrhea During Intermittent Fasting?

Yes, certain foods can trigger diarrhea during intermittent fasting, such as:

1. High fiber foods: These can be difficult to digest and may cause diarrhea during fasting periods.

2. Spicy foods: Spices can irritate the digestive system and cause diarrhea.

When Should I Seek Medical Help for Diarrhea During Intermittent Fasting?

If you experience severe or persistent diarrhea during intermittent fasting, you should seek medical help. This could be a sign of an underlying medical condition that needs to be treated.

Additionally, if you experience other symptoms such as fever, abdominal pain, or blood in your stool, you should also seek medical attention immediately.

Can Medications Help with Diarrhea During Intermittent Fasting?

In some cases, medications may be prescribed to help with diarrhea during intermittent fasting. These may include over-the-counter anti-diarrheal medications or prescription medications to treat underlying medical conditions.

However, it is important to consult with your healthcare provider before taking any medication, especially during fasting periods.

Diarrhea After Fasting: What Are The Causes And Cures


In conclusion, experiencing diarrhea after intermittent fasting is a common occurrence. It is a result of the body’s adjustment to the changes in eating habits. However, it can also be a sign of an underlying health condition that requires medical attention.

To avoid diarrhea while on intermittent fasting, it is essential to stay hydrated, consume fiber-rich foods, and avoid consuming large amounts of food during the eating window. Additionally, gradually easing into intermittent fasting can help the body adjust more easily and minimize the occurrence of diarrhea.

Remember, everyone’s body is different, and what works for one person may not work for another. It is essential to listen to your body, be patient, and make necessary adjustments to ensure that your intermittent fasting experience is a positive one. By doing so, you can reap the numerous health benefits associated with intermittent fasting while avoiding unwanted side effects like diarrhea.

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