Blog Diets Fasting Water Fasting For A Week: Benefits And Dangers

Water Fasting For A Week: Benefits And Dangers

Fasting is nothing new; people have been doing it for centuries as a way to cleanse their bodies and minds. Water fasting is when you drink only water and consume no food for a set period of time. There are many claimed benefits of water fasting, including weight loss, increased energy levels, improved brain function, and enhanced detoxification. Water fasting is also said to help improve your skin health and reduce inflammation (11).

However, there are also some risks associated with water fasting, such as dehydration, electrolyte imbalances, and low blood sugar levels (10). It is important to speak to your doctor before embarking on a water fast, especially if you have any underlying health conditions. Let’s dive into the benefits and risks of water fasting so that you can decide if it’s right for you.

How To Do Water Fasting For A Week?

The idea behind water fasting is that you are giving your body a break from digesting food. When you consume only water, it’s thought that your body can focus on cleansing and repair.

There are different ways to do water fasting. The most common method is to fast for 24 hours, followed by a period of eating normally. This cycle can be repeated as often as you like, for a period of days, weeks, or even months.

Another way to do water fasting is to fast for 36 hours straight, followed by 12 hours of eating normally. This cycle can also be repeated as often as you like.

And finally, you can do a more extreme form of water fasting where you consume only water for 7 days or more. This type of fast is extremely dangerous and should only be attempted under the supervision of a medical professional.

You don’t just wake up one morning and go on a water fast. There’s a method to the madness. For 24 hour fasting, you will want to start by cutting out solid foods the night before. This means no dinner, just soup, broth or juice.

For 36 hour fasting, you will want to start by cutting out solid foods two meals before your fast.

See also
How to Fast for 40 Days? Should You Do It Anyway?

And for 7 days or more, you will want to start by gradually reducing your food intake over the course of a few days, until you are only consuming water.

Note that if you’re a beginner to the world of fasting, you should not attempt a fast that is longer than 24 hours. It’s best to start slow and work your way up as your body gets used to the idea of not eating solid food.

Always talk to your doctor before attempting any type of fast, as it is not safe for everyone.

Water Fasting for a week

How Much Water Should You Drink While Fasting?

It is important to drink plenty of water while you are fasting, as dehydration can quickly set in.

How much water you should drink depends on a number of factors, including your body weight, activity level, and the climate you live in.

As a general rule of thumb, you should aim to drink at least 8 glasses of water per day (12). If you are doing a more extreme fast, such as a 7-day fast, you may need to drink even more water than this. Talk to your doctor for more specific recommendations.

Drinking too much water can also be dangerous, so it is important to listen to your body and drink whenever you are thirsty.

It is also important to stay well-hydrated during the eating periods of your fast. This will help your body to better absorb the nutrients from the food you are consuming.

Read More: Endomorph Intermittent Fasting: How It Works

What Are The Benefits Of Water Fasting?

Some research has been conducted on the benefits of fasting, and there are many possible benefits of doing a water fast.

Some of the most well-known potential benefits of water fasting include:

Weight Loss

One of the most common reasons people fast is for weight loss. When you cut out all food, your body is forced to burn stored fat for energy. This process can lead to rapid weight loss, especially in the first few days of fasting (11).

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Intermittent Fasting for Men: Optimizing Male Wellness

How much weight can you lose from water fasting for a week? Well, it depends. We should probably clarify that most of the changes on the scale will be due to loss of water weight, rather than loss of actual body fat.

You can’t go the rest of your life without food. At some point, you’re going to have to eat again. When you do eat again, the food quality and quantity will play a big role in whether or not you gain all the weight back.

Increased Energy Levels

Another common benefit of water fasting that people claim to experience is increased energy levels (11). When you fast, your body starts to burn stored glycogen for energy. Glycogen is a form of sugar that is stored in your liver and muscles.

After 12-24 hours without food, your glycogen stores will be depleted and your body will start burning stored fat for energy. This process is known as ketosis and some people say it can lead to increased energy levels (11). Other people experience fatigue – different people have different experiences and reactions to fasting.

Water Fasting for a week

Mental Clarity

Many people report feeling more clear headed and focused while fasting. This is likely due to the increased levels of ketones in the brain. Ketones are a byproduct of fat burning which provide energy for the brain when glucose is not available. Some people report improved cognitive function when in ketosis, while others experience the opposite (11).

Improved Digestion

Fasting gives your digestive system a break. When you fast, your body doesn’t have to work as hard to digest food. Some say that this can lead to improved digestion and a reduction in digestive problems like bloating, heartburn, and constipation.

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Reduced Inflammation

Chronic inflammation is linked to a variety of diseases, including heart disease, cancer, and Alzheimer’s disease. Moderate fasting may help reduce inflammation throughout the body, but extended fasting can actually cause damage from oxidative stress and inflammation (11).

See also
Intermittent Fasting for Women Over 60: Discover the Benefits and How to Fast After 60


Fasting has been shown to increase lifespan in some species. While more research is needed to confirm these results in humans (which may not be possible), the autophagy process that occurs during fasting is thought to play a role in longevity (1).

Autophagy is when the body breaks down and recycles damaged cells and organelles. This process helps to prevent the buildup of toxins and might lead to improved cell function (3).

Disease Prevention

Fasting has also been suggested to help prevent a variety of chronic diseases, including type 2 diabetes, obesity, and heart disease (6).

Fasting has also been theorized to improve brain health and protect against neurodegenerative diseases like Alzheimer’s and Parkinson’s disease. This could be due to the autophagy process that occurs during fasting, which helps to clear out damaged cells and promote new cell growth (4).

Fasting has also been suggested to help prevent cancer and slow the growth of tumors (9).

These benefits are far from proven, but they are interesting areas for further study by scientists.

Read More: Intermittent Fasting Side Effects And What You Can Do About Them

Water Fasting for a week

What Are The Dangers Of Water Fasting For A Week?

When water fasting for a week, you may experience some dangerous side effects, such as:


Contrary to popular belief, drinking water only for days doesn’t mean you can’t get dehydrated. In fact, you may become severely dehydrated because your body also needs electrolytes like sodium, potassium, and others to regulate fluid balance (10).


Water fasting for a week can also lead to malnutrition. This is because you’re not consuming any nutrients or calories, which your body needs for fuel. As a result, you may experience weakness, fatigue, and dizziness (10).

You may also be at risk for developing serious health problems, such as organ failure.

See also
The Simplest Intermittent Fasting Guide of 2023

Electrolyte Imbalance

When you fast, your body may also experience an electrolyte imbalance. This is because you lose sodium and potassium through urine and sweat, and you aren’t replacing them by eating food. If not addressed, this imbalance can lead to dangerous consequences, such as heart arrhythmia or seizures (8).

Kidney Damage

Another potential danger of water fasting for a week is kidney damage. This is because your kidneys have to work harder and are affected by the fluid and electrolyte disturbances when you’re neither eating nor drinking, which can lead to strain and damage (5).

If you have kidney problems or are at risk for developing them, water fasting is particularly dangerous.

Muscle Wasting

Another danger of water fasting for a week is muscle wasting. This is because your body will start breaking down muscle for energy since it’s not getting any from food. As a result, you may experience weakness and muscle loss (10).


Gallstones are another potential complication of water fasting for a week. This is because the burning of fat for fuel can cause the release of cholesterol into the bile to increase, which can lead to the formation of gallstones (7).


Diarrhea is another common side effect of water fasting for a week. This is because your digestive system probably isn’t used to not processing food, and as a result, when you break your fast, you may experience diarrhea (10).

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Headaches are another potential side effect of water fasting for a week. This is likely due to dehydration and electrolyte imbalance (10). If you experience a headache while fasting, be sure that you are drinking plenty of fluids and see a doctor if the pain is severe.

Binge Eating

Once you break your fast, you may be tempted to overeat or binge eat. This is because your body will be craving food after days of not eating. While this isn’t necessarily dangerous, it can lead to weight gain and other complications.

See also
Fasting Detox: Foods And Drinks To Detoxify Your Body Safely

People with a history of eating disorders or who are struggling with their weight may want to avoid water fasting for a week.

Orthostatic Hypotension

Orthostatic hypotension is a condition that can occur when you stand up too quickly. When you’re dehydrated, your blood pressure may drop, which can cause you to feel lightheaded or dizzy (2).

If you experience this while water fasting, be sure to drink more fluids and sit or lie down if you feel dizzy. Talk to your doctor and consider breaking your fast.

Water Fasting for a week

What To Do For Weight Loss And Overall Health, Instead Of Water Fasting For A Week

If you’re looking to lose weight or improve your overall health, there are better ways to do it than water fasting for a week. Instead, try making changes to your diet and lifestyle.

  • Cut out processed foods, sugary drinks, and refined carbohydrates. These foods are high in calories and low in nutrients, so they can contribute to weight gain.
  • Increase your intake of fruits, vegetables, and lean protein. These foods are packed with nutrients and can help you feel full longer.
  • Exercise regularly. This can help you burn calories and improve your overall health.

Note that the most effective approach to lifestyle changes is small, gradual changes that you can stick with over the long-term. Crash diets, like water fasting for a week, are not sustainable and can actually be harmful to your health.

If you’re looking to water fast for health reasons, talk to your doctor first. Water fasting is a potentially dangerous practice, and it’s not right for everyone. Your doctor can help you understand the risks and benefits and determine if water fasting is right for you.

The Bottom Line

Water fasting for a week can lead to some dangerous side effects, such as dehydration, malnutrition, electrolyte imbalance, and kidney damage.


This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!


  1. Alternate-day fasting protects the rat heart against age-induced inflammation and fibrosis by inhibiting oxidative damage and NF-kB activati (2010, 
  2. Association Between Dehydration and Falls (2020, 
  3. Autophagy: cellular and molecular mechanisms (2010, 
  4. Effect of 48 h Fasting on Autonomic Function, Brain Activity, Cognition, and Mood in Amateur Weight Lifters (2016, 
  5. Fasting the month of Ramadan by Muslims: could it be injurious to their kidneys? (2007, 
  6. Fasting therapy for treating and preventing disease – current state of evidence (2013, 
  7. Gallstones (n.d., 
  8. General characteristics of patients with electrolyte imbalance admitted to emergency department (2013, 
  9. Intermittent fasting in the prevention and treatment of cancer (2021, 
  10. Is fasting safe? A chart review of adverse events during medically supervised, water-only fasting (2018, 
  11. Is Water-Only Fasting Safe? (2021, 
  12. Water: How much should you drink every day? (2020,
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