7-day Water Fasting: All you Need to Know About Targeting a 7-day Fast Weight Loss

  Mar 18, 2024
Reviewed by Shreya Pasricha

Fasting is nothing new; people have been doing it for centuries as a way to purify their bodies and minds. Water fasting is a method of drinking only water and consuming no food for a period of time. Water fasting is said to have many benefits, including weight loss, increased energy levels, improved brain function, and enhanced detoxification.

Water fasting is also said to improve skin health and reduce inflammation. However, water fasting also carries risks, including dehydration, electrolyte imbalances, and decreased blood sugar levels. It is important to consult a physician before embarking on water fasting, especially if you have an underlying health condition. Let’s delve into the benefits and risks of water fasting to determine if water fasting is right for you.

One-week water fast can be attempted by those who are familiar with the effects of shorter one or three-day water fasts; one-week water fast is more intense than a three-day fast, but is definitely easier for those who have experience with shorter fasts.

It is recommended that you consult with a physician or certified naturopath before undertaking a longer fast. If done carefully, a week-long fast can have tremendous physical, mental, and spiritual benefits.

What is the 7-day Water Fast?

The water diet for a week is an extreme version of the water fast, in which only water is consumed for an entire week.

Some water fasters allow non-caloric beverages such as green tea, herbal tea, club soda, or very low-calorie beverages such as black coffee during the fast.

This not only adds a little variety to what you can drink during a 7-day water fast, but it can also provide an energy boost due to the caffeine you may be accustomed to, while water alone can be very monotonous.

Some 7-day water fasters supplement their water with non-caloric, sugar-free electrolyte powders or electrolyte tablets or capsules.

However, during the rigorous protocol of the 7-day water fast, you are technically only allowed to lick pure pink Himalayan salt.

What are the Benefits of Water Fasting?

Several studies have been conducted on the effects of fasting, and water fasting has many potential benefits.

Some of the best-known potential benefits of water fasting include:

  • Weight Loss

    One of the most common reasons that people fast is for weight loss. By not eating any food, the body is forced to burn stored fat as energy. This process can lead to rapid weight loss, especially in the first few days of fasting. 

    How much weight can you lose on a one-week water fast? Well, it depends. Perhaps I should clarify that most of the change on the scale is due to water weight loss, not actual body fat loss.

    You cannot go without food for the rest of your life. At some point, you will have to eat again. At that time, the quality and quantity of your food will have a significant impact on whether or not your weight will return to normal.

  • Increased Energy Levels

    Another common benefit of water fasting that people claim to experience is increased energy levels. When fasting, the body begins to burn stored glycogen for energy. Glycogen is a type of sugar stored in the liver and muscles.

    After 12–24 hours of not eating, glycogen stores are depleted and the body begins to burn stored fat for energy. This process is known as ketosis, and some people say it leads to increased energy levels. Some people also experience fatigue. Different people experience and react to fasting differently.

  • Mental Clarity

    Many people report that they feel clearer-headed and more focused while fasting. This is thought to be due to increased ketone levels in the brain. Ketones are a byproduct of fat burning and provide a source of energy for the brain when glucose is not available. In some people, cognitive function improves in ketosis, while in others it declines.

  • Improved Digestion

    Fasting gives the digestive system a break. When fasting, the body does not have to work as hard to digest food. As a result, digestion improves and digestive problems such as bloating, heartburn, and constipation are said to be reduced.

  • Reduction in Inflammation

    Chronic inflammation has been linked to a variety of diseases, including heart disease, cancer, and Alzheimer’s disease. While moderate fasting may help reduce systemic inflammation, prolonged fasting can actually cause oxidative stress and inflammatory damage.

  • Longevity in Life

    Fasting has been shown to extend the lifespan of some species. Although further studies are needed to confirm these results in humans (which may not be possible), it is believed that the process of autophagy that occurs during fasting is involved in longevity.

    Autophagy is the body’s process of breaking down and reusing damaged cells and organelles. This process helps prevent the accumulation of toxins and may lead to improved cellular function.

  • Disease Prevention

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

    Some also believe that fasting improves brain health and protects against neurodegenerative diseases such as Alzheimer’s and Parkinson’s. This is due to the autophagy process that occurs during fasting, which is thought to help clean out damaged cells and promote the growth of new cells.

    Fasting has also been suggested to prevent cancer and slow tumor growth.

    Although these effects have not yet been proven, it is an interesting area for further study by scientists. Needless to say, despite acclaimed research, drinking so much water only comes with added benefits for your physical and mental health and well-being. 

    However, it is still a question that leaves many wondering if the 7-day water fasting results are a safe option or not. To ease your worries, the next session is compiled to assess the safety of this water diet and what effects it has on the individual’s health.

Which Water Suits You Best for Water Fasting for 1 Week?

Water is the essence of life, and it is essential to consume it in adequate amounts to maintain good health. Water fasting is a popular trend among health enthusiasts, which involves abstaining from food and consuming only water for a specific period. The duration of water fasting can vary from a few days to several weeks, depending on the individual’s goals and health status.

When it comes to water fasting, choosing the right type of water is crucial. There are several options available, such as tap water, bottled water, mineral water, distilled water, and purified water. Each type of water has its benefits and drawbacks, and it is essential to understand which water suits you best for water fasting for one week.

Tap water is the most common type of water consumed worldwide. It is readily available, and most people have access to it. However, tap water may contain chemicals, such as chlorine and fluoride, which can be harmful to the body when consumed in large quantities. Therefore, it is best to avoid tap water during water fasting.

Bottled water is another popular option for water fasting. It is convenient and readily available in most stores. However, not all bottled water is created equal. Some brands may contain contaminants, such as bacteria and chemicals, which can harm the body. Therefore, it is essential to choose a reputable brand that undergoes rigorous testing and has a good track record.

Mineral water is a type of water that contains minerals, such as calcium, magnesium, and potassium. These minerals are beneficial for the body and can help replenish lost nutrients during water fasting. However, mineral water can be expensive, and not everyone may get to have it.

Purified water is a type of water that has undergone a filtration process to remove impurities and contaminants. It is a safe and healthy option for water fasting, as it does not contain any harmful chemicals or bacteria. However, purified water may lack essential minerals, which can be a drawback for some individuals.

Purified water and distilled water are not the same, although they are both types of purified water. Distilled water is made by boiling water and collecting the steam, which is then condensed back into the water. This process removes all persisting impurities, including chemicals, leaving behind pure H2O. Purified water, on the other hand, can be made through various methods, such as reverse osmosis, deionization, or carbon filtration. While these methods also remove impurities, they may not remove everything, and some minerals may still be present. Therefore, distilled water is considered the purest form of water, while purified water may still contain some trace minerals.

In conclusion, choosing the right type of water for water fasting is essential for maintaining good health and achieving the desired results. It is best to opt for purified water, as it is safe and does not contain any harmful chemicals or bacteria. However, if you have access to mineral water, it can be a good option to replenish lost nutrients during water fasting. Whatever water you choose, make sure to consume adequate amounts and stay hydrated throughout the fasting period.

Is Water Fast for a Week Safe?

While it is not particularly uncommon for people to regularly engage in a 2-3 day water fast, a complete 7-day water fast is quite intense and is neither recommended nor safe for many people.

Fasting for a week may result in adverse health and metabolic changes, including dehydration, loss of lean body mass, hyperuricemia, hyponatremia, protein conservation, sodium conservation, potassium conservation, decreased serum calcium and magnesium levels, and acid urine.

In addition, a 7-day water fast or prolonged caloric and nutritional restriction may result in headaches, nausea, vomiting, constipation, temperature dysregulation, muscle loss, lightheadedness, tremors, poor healing, blurred vision, difficulty sleeping, mood instability, and nutritional deficiencies.

It is imperative to consult a physician and seek medical clearance and guidance before embarking on a 7-day water fast.

What are the Dangers of a 7-Day Water Fast?

Although it’s always encouraged to drink more water, there are ways that can be detrimental to your health if you’re just consuming water instead of food. It is your responsibility to keep yourself aware of both the positives and negatives of this diet, as your health is always the priority.

Water fasting for 1 week can cause dangerous side effects that may include,

  • Dehydration

    Contrary to popular belief, drinking only water for days does not mean that you will not become dehydrated. Rather, you can become severely dehydrated because electrolytes such as sodium and potassium are also needed to regulate fluid balance.

  • Malnutrition

    A  week-long water fast can also lead to malnutrition. This is because the body does not receive the nutrients and calories it needs for fuel. This can result in weakness, fatigue, and dizziness.

    There is also a risk of organ failure and other serious health problems.

  • Electrolyte Imbalance

    Fasting can also cause an electrolyte imbalance in the body. This is because sodium and potassium are lost through urine and sweat and cannot be replaced by food. This imbalance can lead to dangerous situations such as heart arrhythmias and seizures.

  • Kidney Damage

    Another possible danger of a week-long water fast is damage to the kidneys. This is because the kidneys have to work harder when they are not eating or drinking and can be affected by water and electrolyte disturbances, which can cause strain and damage.

    Water fasting is especially dangerous if you have or are at risk of kidney problems.

  • Muscle wasting

    Another danger of a week-long water fast is muscle wasting. This is because the body begins to break down muscle as a source of energy due to the lack of intake from the diet. This can result in loss of strength and muscle loss.

  • Gallstones

    Gallstones are another potential complication of a week-long water fast. This is because burning fat as fuel increases the release of cholesterol into the bile, which can lead to the formation of gallstones.

  • Diarrhea

    Diarrhea is another common side effect of a water fast for a week. This is because the digestive system is probably not accustomed to not processing food, and as a result, the fast may result in diarrhea.

  • Headaches

    Headache is another possible side effect of a week-long water fast. This may be due to dehydration and electrolyte imbalance. If you experience a headache during the fast, make sure you are drinking enough water, and see a doctor if the pain is severe.

  • Binge Eating and Drinking

    Once the fast is over, you may be tempted to overeat or binge eat. This is because, after days of not eating, your body will crave food. This is not necessarily dangerous but can lead to weight gain and other complications.

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

  • Orthostatic Hypotension

    Orthostatic hypotension is a symptom that can occur when one suddenly stands up. When dehydrated, the blood pressure drops and the person may feel lightheaded or dizzy.

    If you experience these symptoms during a water fast, drink more water and sit or lie down if you feel dizzy. Consult your physician and consider interrupting your fast.

    Well, certainly that’s a lot of detrimental effects that can distress your body if the water fast for a week doesn’t bode well with you. However, there’s no need to fret. The next section provides you with safe and healthy options to lose weight instead of intense water fasting for a week because staying healthy is the end goal here.

How to Approach Weight Loss Instead of a Week’s Worth of Water Fasting?

If you are looking for a 7-day fast weight loss plan or to improve your overall health, there are better ways to do so than doing a week-long water fast. Instead, make some changes to your diet and lifestyle.

  • Cut back on processed foods, sugary drinks, and refined carbohydrates. These foods are high in calories and low in nutrients, which can cause weight gain.
  • Increase your intake of fruits, vegetables, and lean protein. These foods are rich in nutrients and help you feel fuller longer.
  • The most effective way to change your lifestyle is to make small, incremental changes that can be sustained over time; drastic diets, such as a week-long water fast, are not sustainable and can actually be detrimental to your health.

If you are going to do water fast for health reasons, consult your doctor first. Water fasting can be a dangerous practice and is not suitable for everyone. Your physician can help you understand the risks and benefits and determine if water fasting is right for you.

Although the water fast for 1 week can be intimidating and have detrimental effects on the body, a water fast is still a good way to detox if done in moderation, for instance, not more than 3 days. 

Meanwhile, if you’re still convinced to at least give the water fasting for 7 days a try, don’t worry. I would still advise you to approach water fasting with caution and moderation. If done in moderation and with proper guidance from your physician, it can also provide amazing benefits to your mental and physical well-being.

How to Prepare for a 7-day Water Fast?

In traditional medicine, such as naturopathy, long-term fasting is recommended for a variety of health benefits. In such cases, fasting is done under the supervision of a qualified physician and can be done as directed by the physician. It can also be done at home with at least five days of fasting experience. Ideally, it should be done at a naturopathic center under the guidance of a certified instructor.

Note that fasting is equally important. After fasting, it may take approximately 4–5 days to return to a normal diet. Therefore, be prepared for the entire process to take 11–12 days.

  • The first step is to prepare yourself for the practice. First, it is important to overcome the fear of trying a long fast. Build your confidence with the guidance of an expert. 
  • It is also a good idea to understand the basic principles of fasting and the various physical reactions during fasting. There are many books on natural healing that can help. 
  • Also, read about the experiences of people who have tried long fasts and learn about their experiences. This will give you the confidence to try fasting.

A healthy person can go weeks without eating. So fasting for a week is not difficult if done carefully. Once the fast is complete, you will experience the great health benefits associated with fasting. However, if you are suffering from a serious illness, consult your doctor before fasting. 

People with specific contraindications, such as tuberculosis or other infectious diseases, should not fast for long periods of time. Pregnant women should also avoid long-term fasting.

How to do a 7-day Water Fast?

Simply put, the 7-day water fast is simple: drink only water for 7 days.

As mentioned earlier, the first step is to consult with a healthcare professional so that you can prepare yourself for the practice in order to overcome your fear and, furthermore, undertake a medically supervised water fast.

The next step is to prepare yourself physically, mentally, and emotionally for a week of water fasting.

While it is certainly possible and permissible to begin a water fast out of the blue to prepare physically for a 7-day water fast, it is a good idea to practice with shorter water fasts before attempting a week-long fast.

For example, one week before a 7-day water fast, try a 24-hour water fast, or one or two days before a 1-week water fast. Try a 20/4 fast (20 hours of extended fasting at night, with food intake only 4 hours during the day) for several days.

Although not required, this “mini” fast allows your body to experience what it feels like to not take in calories, even when your energy is low, and hunger signals stimulate you to eat.

If you do not normally fast or water fast, suddenly abstaining from all food and energy intake for a week can be a shock to your system and a difficult transition.

Even if you decide before beginning a 7-day water fast that you do not want to experiment with fasting, it is still a good idea to be mindful of your food choices for 48 to 72 hours before beginning your water fast.

Avoid processed foods, especially those high in sugar and artificial sweeteners, such as sodas, as they can increase your appetite. Concentrate on eating nutrient-dense, unprocessed foods such as vegetables, fruits, lean proteins, nuts, seeds, and eggs.

A woman choosing apples over donuts

While it is natural to be tempted to “buy and eat” or “binge” as you approach the 7-day water fast, overeating can make the rapid decrease in caloric intake seem more difficult. It has the potency to undermine the health and weight loss benefits of water fast.

In addition to physically preparing yourself for a week of water fasting, you need to prepare your mind for what is about to happen.

Abstaining from all food and caloric drinks for a week can be extremely challenging.

You will experience physical and emotional sensations that will test your mental strength and discipline.

It is a good idea to have some self-care tools and strategies to help you relax and reflect, such as meditation, journaling, prayer, music, podcasts or audiobooks, walks, and art.

During the fast, you are not allowed to eat any type of food or drink sweetened beverages.

If you experience any worrisome symptoms, consult your doctor immediately.

What Happens During a 7-Day Water Fast?

There are several reported phases that the body goes through during a 7-day water fast. Here are the phases of the fast.

  • 12-hour water fast

    After about 12 hours of fasting, the body enters a state of ketosis as it begins to use up stored muscle and liver glycogen. This is done by breaking down and oxidizing fats instead of carbohydrates for energy.

  • Water fasting for 18 hours.

    Ketosis begins with about 12 hours of fasting, but by 18 hours, the body begins to burn fat as its primary fuel source and produces more ketone bodies.

    These ketones, but not glucose, serve as the main source of fuel for the cells.

  • 24-hour water fast

    At the end of the 24-hour water fast, the autophagy process is said to begin.

    Autophagy is a cellular cleaning process that removes dead or damaged cells and cleans the body.

    Valid cellular components and proteins are recycled, while damaged or misfolded proteins, such as those associated with neurodegenerative diseases such as Alzheimer’s, are destroyed. Further aiding in protecting the body from such diseases and other causes of oxidative damage and premature aging.

  • After 40-50 hours of water fasting

    After 2 days of water fasting, your human growth hormone (HGH) levels may have increased up to 5 times above normal resting levels.

  • After 60 hours of water fasting 

    Insulin levels drop to their lowest level, and cellular sensitivity to insulin reaches its peak.

  • After 72 hours of water fasting

    After three days of water fasting, the body begins to destroy old immune cells and produce new, healthy immune cells.

    It is evident that due to this process, the body goes through an intense detox and clarifies the bodily systems. It is still up to personal discretion if these 7-day water fasting results are actually worth risking the safety of your body from all the risks mentioned above.

What to Eat After You’re Done with 7-day Water Fasting?

After completing a 7-day water fast, it is essential to reintroduce food gradually to avoid any digestive issues. Start by consuming small portions of easily digestible foods such as steamed vegetables, bone broth, and fruit. Avoid consuming processed and high-fat foods, as they can cause discomfort and digestive problems. 

Incorporate probiotics and fermented foods such as yogurt, kimchi, and sauerkraut to replenish the gut flora. It is also essential to hydrate your body by drinking plenty of water and consuming electrolyte-rich drinks such as coconut water. 

Coconut with a straw

Gradually increase your food intake over the next few days and listen to your body’s signals to avoid overeating. By following these guidelines, you can ensure a smooth transition back to a regular diet after a water fast.


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Ans: 10% of body weight

Ans: Adverse health and metabolic conditions such as dehydration, loss of lean muscle mass, hyperuricemia, hyponatremia, protein-sparing, sodium, and potassium-sparing, decreased serum calcium and magnesium levels, and acidic urine

Ans: 4-6 Kg of fat reduction within 1 week

Ans: A prolonged limitation on food consumption can ultimately lead to a decrease in lifespan.

Ans: You should not exceed your water fast for more than 24 hours to a maximum of 3 days.

Ans: 48 hours

Ans: There is no guarantee that fat will be reduced in specific areas or that waist measurements will decrease.

Ans: If water is your primary (or sole) source of nourishment, your body will experience a deficiency in vital nutrients.