The Highway To Hydration: What Are The Benefits Of Water Fasting?

Discover the Health Benefits, Risks, and Inner Workings of Water Fasting

Table of Contents

What is water fasting?

Everyone knows that eight glasses of water a day is the minimum you need to stay hydrated and for your body to function the way it should. What if those eight glasses were all you consumed in one day?


Water fasting is a practice where you don’t eat any solids or food. In some cases, small amounts of juice or broth are consumed, but most strict practitioners stick to plain water. Fasting is an ancient practice, and many religions follow different versions of it.


During Ramadan, members of the Islam community fast from sunrise to sunset, and do not consume water. People who practice Christianity fast during Lent. Modified versions of Lent involve abstaining only from certain foods. Buddhists and Hindus often have noon to noon fasts, consuming small amounts of food exclusively in the mornings. Medicinal forms of fasting date back to ancient Chinese, Indian and even Greek and Roman cultures! It’s rumored that Pythagoras once fasted for forty days before his exams at the famous Alexandria school, but that particular practice might not help you ace your finals.

A sculpture representing the Buddha after his famous fast, Credit: WIkipedia/World Imaging

In more recent times, activists and political figures have undertaken extreme forms of water fasting in order to express political discontent, typically known as a “hunger strike”. Women suffragettes in the U.S and U.K undertook hunger strikes in order to garner attention for voting rights. Alice Paul was a suffragette who famously led her fellow prisoners in protest. At Occoquan workhouse, a prison in Virginia, Paul and others fasted for two weeks! This symbolic sacrifice can be a powerful way to raise awareness.


From spiritual beliefs to advocacy, the reasons people fast are varied and complex. Researchers have been examining the risks and benefits of such practices, and many of these traditions do seem to have certain health benefits.

Is water fasting good for you?

The primary reason fasting is thought to have so many different health benefits and impacts is because of its effect on metabolism . The human body is a complex machine, with a ton of moving parts! Eating is vital for the body to function. The nutrients and energy we get from food help our heart beat, muscles move and brain to think. Since food influences every part of the body, any change in food intake changes the way almost every part of our body functions.


Metabolism involves two main processes – building up and breaking down. Human bodies are incredible recyclers. Every molecule is a part of dozens of structures before it gets discarded. Food gets broken down to first make energy, and then the remaining molecules are built up into muscles, bones and fat.

same molecules
The same molecules are reused in many structures

During a fast, the priority for the body is figuring out where to get energy from when there’s no longer any food coming in. It begins to break down muscles and fat tissue to get protein and energy. This is why weight loss is often the primary effect of a fast. Over a long fast, metabolism might slow down so that the body can conserve energy. This leads to many of the side effects of hunger, like headaches, dizziness and brain fog. One study examined different fasting protocols, and found that on average only one third of the weight lost was fat. The other two thirds was muscle mass. However, even after the fast is completed and normal diet resumes, weight loss can be maintained.


Since the body is breaking down existing tissues for energy, a process called autophagy is triggered. Old cells are remade into new ones. This seems to have an anti-ageing effect, as well as improve heart health. Research is still ongoing as to why autophagy benefits the body, but it seems to have something to do with the clearing out of damaged, old cells. It’s like spring cleaning!


Water fasting might also be excellent for people who may develop diabetes. Irregularity in insulin production and the body’s ability to respond to it are the main causes of diabetes. During a fast, the body is working overtime to strictly maintain blood sugar. This might improve the functioning of insulin, a hormone that is responsible for controlling blood sugar. Fasting might be a promising treatment for diabetes.

Is water fasting safe?

Although water fasting does seem to have some benefits, it’s important to recognise the risks too.


The first few hours or days after a long fast are crucial. After the body adjusts to very little or no food, suddenly having a feast can lead to shock. It’s important to start slowly, with soups, broths or smoothies. Sudden intake of large amounts of food can affect the brain, heart, and lungs, and even cause mortality in severe cases.

During Ramadan, Muslims typically break their fast with a date. Dates are high in sugar, making them an energy rich but small meal with which to break a fast, Credit: Wikimedia/ORGANIChouse

Funnily enough, water fasting can sometimes cause dehydration! If you’ve ever played a tournament or run a marathon, you know the importance of consuming electrolyte drinks rather than water. Consuming only water can lower the amount of salts and sugars in the blood, and this altered balance between water and salts is actually what causes symptoms of dehydration. Sports drinks and electrolyte salts can lower the risk of dehydration, as well as complications when resuming food.


For those with minimal muscle mass, a sudden loss of muscle caused by fasting can cause further problems. Additionally, those with diabetes, gout, or eating disorders should avoid water fasting, or do it under the care of a medical professional if it is absolutely necessary.


Whether it’s for religious reasons, political advocacy, or for the health benefits, water fasting needs to be safe. Always consult with a doctor or primary-care physician before undergoing changes in diet.

Flesch Kincaid Grade Level: 9.1


Flesch Kincaid Reading Ease: 57.6


Autophagy: The breaking down of old cells and tissues


Metabolism: The chemical reactions that help the body function, broadly categorized as “building up” and “breaking down”


  • Yamini Srikanth
    : Author
    Yamini's (he/they) interests lie in environmental education, science communication and trying to build a better world. When not languishing in front of his laptop, they can be found outside, poking at any insect, bird or plant. They love making science accessible, especially to those who aren't encouraged to pursue it. Yamini hopes that the young women who read Smore love learning from their articles and get just a little bit more excited about science!

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