Top 13 Signs To Stop Water Fasting

Water fasting is a type of fasting that involves consuming only water for a specific period of time, typically ranging from a few days to several weeks. This practice is believed to have various health benefits, including weight loss, improved insulin sensitivity, and a reduction in inflammation. However, as with any type of fasting, it is important to be aware of the potential risks and signs to stop water fasting.

In this article we will discuss the benefits of water fasting and the many signs that indicate it may be time to stop.

Benefits of Water Fasting

One of the most notable benefits of water fasting is weight loss. By drastically reducing the number of calories consumed, the body is forced to burn stored fat for energy.

This can lead to significant weight loss, especially in the first few days of the fast. Additionally, water fasting may also improve insulin sensitivity, which can lead to better blood sugar control and a reduced risk of diabetes.

One final potential benefit to water fasting, or fasting in general, is it’s affects on inflammation. Studies have shown that water fasting can lead to a reduction in inflammation markers, which may have a positive impact on conditions such as rheumatoid arthritis and other inflammatory conditions.

Despite its potential benefits however, water fasting is not without risks. It is important to be aware of the warning signs that indicate it may be time to stop the fast.

Related: Water Fasting and Workout Out: Good or Bad?

13 Signs to Stop Water Fasting

So, here are the top 13 signs to stop water fasting:

1. Fatigue

Weakness or fatigue is a common symptom during a water fast and is a sign that the body is not getting enough energy. Which is to be expected if you are drastically reducing your intake of calories and nutrients.

Whilst the body is quite adept at surviving a reduction in calorie intake, if you feel weak or fatigued it may be a sign that your body is not tolerating the fast well and it’s important to stop the fast and consult with a healthcare professional.

It’s also important to note that during a fast, the body’s energy is purportedly directed towards detoxification and repair processes, which, if true, may be the reason for the fatigue. Although this is debated.

2. Dizziness

Dizziness or lightheadedness is a symptom that can occur when the body’s blood sugar level drops too low.

This can be caused by a lack of carbohydrate intake as a result of the fast, and it can be dangerous if not addressed.

It can take some time for the body to switch to gluconeogenesis, where the body synthesizes its own glucose from non-carbohydrate sources, and adding this on top of the pressures of adapting to zero foods, let alone just a reduction in carb, can be cause for concern. 

3. Nausea or Vomiting

Nausea or vomiting is a common symptom during a water fast, and it may indicate that the body is not tolerating the fast well. It may also be a sign that the fast is too restrictive for the individual, and the body is not getting the nutrients it needs.

4. Constipation or Diarrhea

Constipation or diarrhea can occur during a water fast as the body adjusts to the lack of food intake.

We as humans not only hydrate ourselves from water, but we also receive a significant amount of hydration from the food we eat as well.

Suddenly restricting that could result in dehydration like symptoms and this should be addressed immediately if suspected.

5. Headaches

Headaches or migraines may occur during a water fast, and it may be a sign that the body is not getting enough electrolytes such as sodium.

These symptoms may also be caused by dehydration and can be very debilitating. Many athletes are at risk of electrolyte deficiency through activity.

If you are an active athlete who is also undertaking a water fast you need to make sure you’re replenishing electrolytes where possible.

 6. Irritability

Irritability or mood swings: Irritability or mood swings can occur during any overly restrictive diet. But these are more likely during a water fast due to the excessive nature of the restrictions.

These symptoms may also be caused by changes in blood sugar levels. If you are currently struggling with your mental health, you should avoid a water fast and seek medical direction if you feel you need to take part in a diet.

 7. Difficulty Concentrating

Difficulty concentrating or thinking clearly can occur during a water fast, especially during the early stages.

Many people who begin a classic 16:8 intermittent fast experience similar symptoms, and these can be exacerbated during a water fast. If your job requires sound mind it may be best to avoid a water fast.

If you wish to take part in one anyway and find you are struggling with concentration, then you should consider stopping the fast immediately.

8. Loss of Muscle Mass

Loss of muscle mass or muscle weakness can occur during a water fast, and it may be a sign that the body is breaking down muscle tissue for energy.

As muscle development is an anabolic process, there is always a risk of muscle loss during a dieting phase. Especially during a fast. As you are putting the body in a net-catabolic state.

During this phase the body is searching for convenient sources of energy. Glycogen is often the first place it looks, followed by stored calories (fat/triglycerides).

Often times, however, during prolonged periods of restricted eating the body will turn to muscle mass.

If you are concerned about a drop in muscle mass, you should consider breaking the fast and increasing your protein intake.

9. Heart Palpitations

Rapid heartbeat or palpitations: In response to an electrolyte imbalance you may start to experience heart palpitations, or a rapid heartbeat even at rest. This can be very debilitating and if experienced you should break the fast and seek medical attention to resolve the electrolyte imbalance.

10. Reduced Urination

Reduced urination or dark-colored urine: Reduced urination or dark-colored urine can occur during a water fast and may be a sign that the body is extremely dehydrated.


IMPORTANT: It’s important to consult with a healthcare professional before starting any fasting regimen and to stop fasting if you experience any of these symptoms or other adverse effects. Additionally, people with certain medical conditions or on certain medications should avoid water fasting.

Additional warning signs that you should stop a water fast includes:

11. Rapid weight loss

Losing weight quickly can be dangerous and can cause a variety of health problems.

Many of the risks have been listed above, but additional risks of rapid weight loss can include thinning hair, cramps, loss of menstrual cycles and more.

12. Low Blood Pressure

Low blood pressure: Extreme low blood pressure as a result of the sudden reduction in food may cause excessive dizziness and concentration problems.

If you find yourself faint a lot, break the fast immediately.

13. Gallbladder or Liver Problems

Gallbladder or liver problems: If you already have pre-exsting liver problems, or are sensitive to gallstones, you may exacerbate these by undertaking any fast, due to an increase in bile.

If you experience any issues, consult your doctor immediately.

Bottom Line

As you can see, despite it’s purported benefits, there are many signs to stop water fasting. If you or someone you know is attempting one, keep an eye on the above. And contact a medical professional if you have any concerns.

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Mike Julom, ACE CPT

Mike is an ACE Certified PT and a CrossFit Level 1 Trainer. He is an avid lover of all sports. Basketball, tennis, athletics, volleyball, soccer, squash, golf, table tennis, even darts, you name it! He's a very active CrossFit athlete and has been WOD'ing for over 7 years. With such an intense fitness regime, Mike has learned to take care of his body physically, nutritionally, and spiritually. Mike founded ThisIsWhyImFit as a way to share his vast knowledge of exercises, diets, and general fitness advice.

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