How To Do A 7 Day Water Fast + What To Expect

A 7 day water fast is very extreme and a much stricter iteration of fasting diets compared with standard time-restricted eating intermittent fasting, such as intermittent fasting 18/6, where you fast for 18 hours in the day and then permit eating during six hours or even alternate day intermittent fasting, where you only consume food every other day.

Studies have shown that extended fasting, such as water fasting for a week or more, can result in positive effects like weight loss, body fat loss, reduced levels of perceived stress, increased ketogenesis, and decreased blood sugar levels. 

However, there are also many potential risks associated with 7 day water fasting.

In this article, we will discuss how to do a 7 day water fast and the potential risks that come along with it.

We will cover: 

  • What Is a 7 Day Water Fast?
  • Is 7 Day Water Fasting Safe?
  • How To Do A 7 Day Water Fast
  • What Happens During a 7 Day Water Fast?
  • What to Eat After a 7 Day Water Fast

Let’s dive in! 

A person drinking a glass of water.

What Is a 7 Day Water Fast?

A 7 day water fast is an extreme version of water fasting that involves consuming only water for one full week.

Some people who practice water fasting permit non-caloric beverages like 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 are able to drink during a 7 day water fast, as only water can get quite monotonous, but it also can provide the energy boost from caffeine that you might be accustomed to.

Some people who do 7 day water fasting also supplement their water with noncaloric, unsweetened electrolyte powders or electrolyte tablets or capsules.

However, during strict 7 day water fasting protocols, you are only technically allowed to lick pure pink Himalayan salt.

Himalayan salt.

Is 7 Day Water Fasting Safe?

It’s not particularly uncommon for people to periodically do a 2 to 3-day water fast, but a full 7 day water fast is quite intense and not recommended nor safe for many people. 

Fasting for a week may result in adverse health and metabolic changes such as dehydration, a loss of lean muscle mass, hyperuricemia, hyponatremia, protein-sparing, sodium, and potassium-sparing, decreased serum calcium and magnesium levels, and acidic urine.

Additionally, a 7 day water fast or long-term caloric and nutritional restriction can result in symptoms such as headaches, nausea, vomiting, constipation, the inability to regulate body temperature, muscle loss, lightheadedness, shakiness, poor healing, blurry vision, difficulty sleeping, mood instability, and adverse nutritional deficiencies.

If you are going to embark on a 7 day water fast, it is imperative that you speak with your doctor beforehand and seek medical clearance and guidance before you begin.

Someone speaking with their doctor.

How To Do A 7 Day Water Fast

So, how do you do a 7 day water fast?

As mentioned, the first step is to speak with your healthcare provider so that you can do a medically-supervised water fast.

The next steps are to physically prepare your body and mentally and emotionally prepare your mind to water fast for a week. 

In terms of physically preparing your body for a 7 day water fast, although it is certainly possible and permissible to jump right in and just begin water fasting, it’s often a good idea to practice with a shorter water fast before you take on a full week of fasting.

For example, you might try a 24-hour water fast one week before your 7 day water fast or a few days of 20/4 intermittent fasting (extending your overnight fast for a full 20 hours and then only allowing the consumption of food during a 4-hour window during the day) for a week or two before the week-long water fast.

An empty plate.

Although not mandatory, these “mini” fasts will give your body a taste of what it will feel like to have no caloric intake even when your energy is low, and hunger signals may try to stimulate you to eat.

If you do not regularly practice intermittent fasting or do any kind of water fasting protocol, it can be a shock to the system and a difficult transition to suddenly abstaining from all food and energy intake for a full week.

Even if you decide you do not want to do any kind of fasting experimentation before you begin your 7 day water fast, it’s a good idea to be mindful of your food choices in the 48 to 72 hours before you begin your water fast.

Avoid processed foods, particularly those high in sugar and artificial sweeteners, as these can trigger appetite.

Focus on eating nourishing, unprocessed foods such as vegetables, fruits, lean proteins, nuts, seeds, and eggs. 

A pan of cooked vegetables.

Although there’s a natural tendency to want to “stock up“ or binge with a big meal heading into a 7 day water fast, overeating can actually make the sudden drop in caloric intake feel more challenging, and it can compromise some of the potential health and weight loss benefits of water fasting that you’re striving for.

In addition to the physical preparation for water fasting for a week, you will need to prepare your mind for what is about to happen. 

There’s no way around it: abstaining from all food and caloric beverages for a full week is extremely challenging. 

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

Whether you like to meditate, journal, pray, play music, listen to podcasts or audiobooks, take walks, or do some form of art to help you relax and center yourself, it’s a good idea to have a few tools and strategies in your self-care arsenal that you can use during tough times with your water fast.

Actually doing a 7 day water fast is simple—drink only water (and/or plain tea or black coffee if you want) for a full seven days.

You cannot eat any type of food or sweetened beverage during the fast.

If you experience any type of concerning symptoms, you should consult your doctor right away.

Pour a glass of water.

What Happens During a 7 Day Water Fast?

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

12 Hours Of Water Fasting

After about 12 hours of fasting, your body will start to run out of stored muscle and liver glycogen, so you will shift into a state of ketosis. This involves breaking down and oxidizing fat for energy instead of carbohydrates.

18 Hours Of Water Fasting

Although ketosis begins after about 12 hours of fasting, by 18 hours, your body is primarily burning fat for fuel, so you are generating much higher levels of ketones. 

These ketones are serving as the main fuel source for your cells rather than glucose.

A glass of water with electrolyte powder.

24 Hours Of Water Fasting

After a full 24 hours of water fasting, the process of autophagy is said to begin.

Autophagy is the process of cellular debridement, in which dead and damaged cells are removed and cleaned up around your body. 

Viable cellular components and proteins might be recycled, while damaged and misfolded proteins, such as those linked to neurodegenerative diseases like Alzheimer’s, are destroyed, helping protect your body from such diseases and other sources of oxidative damage and premature aging.

After 48-60 Hours Of Water Fasting

After 2 days of water fasting, your level of human growth hormone (HGH) may have increased up to fivefold over normal resting levels.

Around the 60-hour mark of a water fasting protocol, your insulin levels will have dropped to their lowest level, and your cells’ sensitivity to insulin will peak.

After 72 Hours Of Water Fasting

Once you have been water fasting for three days, your body will start destroying old immune cells and generating new, healthier immune cells.


What to Eat After a 7 Day Water Fast

After your 7 day water fast is over, it’s important to carefully and strategically plan what you are going to eat.

A dangerous condition known as refeeding syndrome can occur if you eat too much too soon after fasting for so long.

Refeeding syndrome is caused by the rapid changes in electrolytes and water balance that can occur once you finally give your body some nutrients.

Certain electrolytes, such as potassium, magnesium, and phosphate, are required for digesting and absorbing nutrients, particularly carbohydrates.

The levels of these electrolytes can drop significantly during a 7 day fast, substantially impairing your ability to process incoming nutrients once you break your fast.

You need to gradually ease back into eating and choose foods to break your fast that are lower in carbohydrates and gentle on the stomach. 

Typically, fermented foods, bone broth, and cooked vegetables are a good starting place, but it’s important that you get individualized guidance from your healthcare team.

Ultimately, it’s important to work closely with your doctor and strongly consider safer alternative approaches to dieting.

If you want to take your fasting project on little by little, check out our guides to 24-hour and 36-hour fasting first.

Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, and contributes to several fitness, health, and running websites and publications. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.