Water fasting to loose weight… Does it work?

By Krystal Dollery
Sep 21 2022

Water fasting to loose weight… Does it work?

Can Water Fasting Help with Weight Loss?

Angry because you are on the losing side of negotiations with the bathroom scale? We have all been there! This is usually followed by an evaluation of lifestyle habits and some sort of bargaining.

Naturally, our first line of defense is to blame the food as a culprit and look for simple ways to cut back. 

Let’s be honest, none of us actually likes cutting out the food we love, especially for an extended period of time. If we did, we would not be going through the five stages of grief as we toss our favorite snacks in the trash and curse our Ding Dong addiction. It’s not fun. With any restriction, we like to consider what the basic necessities are in order to functionally thrive while simultaneously achieving our goal. 

This brings us to the age old question: Does water fasting to loose weight work?

Water fasting to loose weight

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What is water fasting?

Intermittent fasting has been a pretty popular term in the weight loss industry over the last couple of years so it’s no surprise that the combination of water fasting and intermittent fasting has come to the forefront. 

Water fasting is when daily consumption is limited to only drinking water for a specific amount of time. By doing this, we are preventing ourselves from our urge to binge eat and take in excessive calories, the dirty little devil responsible for tipping the scales in favor of gravity and chronic diseases such as heart disease,coronary artery disease, and other metabolic diseases.

Benefits of water fasting?

Before succumbing to such gross palatic deprivation of a water fast, it’s worth examining if the juice (or lack thereof) is worth the squeeze. In other words, what are the health benefits of water fasting?

Water fasting creates a calorie deficit–the tried and true weight loss approach that’s responsible for success on a global scale. 

Our bodies require energy, from the calories in food, to function. Excessive energy is stored as fat, whereas a lack of energy nudges the body to dip into its reserves of body fat to operate and this is how we burn fat. By water only fasting, our bodies are forced to use stored fat rather than calories we are actively giving it.

Another one of the health benefits of water fasting is it helps us feel full by filling up the tank.

A full belly is a happy belly, we are less likely to binge eat if our stomach is not signaling to the brain that the tank is running low.

Water fasting keeps us hydrated. 

We lose water through a variety of ways: sweat; urination; tears from the fact we have to cut out the cookies. Water fasting is a surefire way to ensure that the lost fluid is replenished. 

Water fasting aids in the management and prevention of chronic diseases.

Risks for many chronic diseases such as high blood pressure, heart disease, and cardiovascular disease can be reduced by water fasting. Furthermore, insulin sensitivity, blood pressure, and diabetes mellitus have been shown to improve with medically supervised water fasts.

Health complications to water fasting for weight loss

Water fasting should be monitored by a healthcare provider in order to prevent potential medical conditions or the development of eating disorders. 

Pregnant women should seek medical supervision if considering a water fast to burn fat as the risks of chronic disease and nutrient deficiencies outweighs the benefits of water fasting.


Wait, but you just said…huh? The tricky business with water fasting is making sure we are consuming enough water. By cutting out solid foods from a healthy diet, we are also cutting out alternative sources of water we may have been unknowingly ingesting.

It’s crucial to seek out professional medical advice from a licensed healthcare provider before and throughout your water fast for medical supervision. 

Water intoxication

Much like getting chocolate wasted, we can also get water wasted from water fasting. In other words: too much of a good thing can cause some major risk factors. 

Water poisoning is the opposite of dehydration, it’s when a water fast leads us to drink so much we flush out important electrolytes needed for brain performance and health benefits. This is among the more serious health conditions to consider during your fasting period as it’s a potentially fatal condition. 

It’s always wise to consult with wellness professionals before you engage in water fasting for disease prevention and evaluation of medical conditions which may be affected by a water fast. 

Frequent urination

Pretty self explanatory and, although not a major health condition, it’s definitely not pleasant as it may cause digestive discomfort. The increase of uric acid has been linked to gout flare ups. 

Nutrient Deficiencies

Continuous energy restriction from prolonged fasting poses many health risks, one of which is the lack of nutrition from the significant reduction of food in the water fasting process. 

It goes without saying that medical supervision is highly recommended when considering water fasting as some eating disorders, low blood pressure, drops in blood sugar, and uric acid induced gout flare ups may potentially be affected. Although water fasting may help in lowering blood pressure, this is only helpful in instances when blood pressure is already high. 

How much water should I drink to lose weight?

So how much water should we consume to achieve our goal and dance on that line between tinkling and tipsy when doing a water fast?

Many factors come into play when water fasting, especially when we consider things like activity level, heat, the body’s metabolism and how many calories we are burning. We don’t want to drink so much that we are forced to constantly duck out of the work meeting (or maybe we do?) to “water the flowers,” but we do want to drink enough to stay hydrated and full. 

For some, this may be two liters, for others it may be more. Many will suggest a full gallon when water fasting, but remember that that suggestion is based on the idea that we are replenishing our electrolytes through food.

 A good rule of thumb for water fasting is to take your current weight and divide by two in order to get an estimated amount of ounces recommended for you, however, medically supervised water fasts will routinely monitor and recommend amounts of fluid appropriate for your individual needs.

How long should I fast to lose weight?

Like with all attainable goals, water fasting for weight loss should be approached with the marathon mindset. Sure, you can sprint out the gate and you may be successful, but why risk a chance at failure when you are already attempting something as difficult as water fasting? 

Start out slow, get your feet wet, so to speak.

 Jumping into outrageous 20/4, 7 day water fasting is a recipe for disaster. Instead, try the one-day-at-a-time, intermittent fasting approach: water fasting for one day then taking a day off, followed by two days of water fasting and a day off your water fast, steadily increasing to the desired timeline. 

The recommended amount of time for a water fast is up to 72 hours, as any longer may pose health risks if not evaluated by a medical professional. 

Helpful tips:

Setting small attainable goals will not only boost your self-confidence, but it will help build mental endurance for a longer water fasting goal. If you’re pressed for time and have Jedi willpower, it’s absolutely doable to tackle a full 72 hour water fast right out the gate, however expect it to be uncomfortable. It’s wise to prepare the body for such a drastic change by slowly decreasing food intake in the days prior to water fasting. 

Use of a food diary is an excellent way to track the gradual tapering of calories in preparation for your water fast as well as to prevent developing an eating disorder and other unhealthy eating habits.

The Nitty Gritty for Water Fasting Weight Loss

So now that we know the how-to’s and the what-for’s, it’s time to evaluate a water fast as an effective means for weight loss. 

It’s not the water fast per say that is causing weight loss, rather the caloric restrictions by the lack of food consumption imposed by only taking in water. We know the not-so-secret secret of losing body fat is to create a calorie deficit and by consuming a calorie-free diet of only water, we will be doing exactly that, but how realistic and successful is it? 

It’s estimated that a 3,500 calorie deficit per week will result in approximately one pound of fat loss. 

Your activity level and the length of the water fast are going to play a large role in that total deficit. A short term water fast is unlikely to produce the necessary requirements to fulfill this demand; however, after healthy preparation or long term water fasting, there may be an opportunity to burn stored fat. 

Take into account that our bodies will be flushing water rapidly, so this will account for a change in the scale; unfortunately, we don’t operate on water and sunshine so this change to our body weight is likely to reverse upon “refeeding” as our bodies replace the lost fluids. Bear in mind, the sudden loss of water can be attributed to blood pressure problems.


Although there may be some overall health benefits of water fasting that may increase your life span, water fasting can also negatively affect your blood pressure, blood sugar, and kidney function which in turn may shorten your life span.

While water only fasting can pose long term benefits, when implemented in a healthy manner and over an extended period of time, the more immediate weight loss benefit favors the temporary shedding of water weight to achieve a leaner look rather than immediate fat loss. In other words, don’t expect a significant change in your body mass index or muscle mass.

If you’re looking for a way to lose weight quickly but not permanently, with extreme calorie restriction, water fasting may be the more appealing answer; however, adjusting eating habits for a more balanced diet is ultimately the best method of losing weight and poses more health benefits. 

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