How Much Water Should I Drink While Fasting

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How Much Water Should I Drink While Fasting

The question “how much water should I drink while fasting” often comes up when deciding to partake in intermittent fasting.

Currently one of the mainstream strategies for shedding unwanted pounds and improving your overall health, intermittent fasting involves abstaining from eating food for a set time period but not from drinking water.

A crucial part of surviving your fast is staying hydrated. Drinking enough water is essential, especially when partaking in a prolonged fast.

This article aims to help you learn more about the role of water in your body, how much you should drink, and why it’s essential in your fasting journey.

How Intermittent Fasting Works

Intermittent fasting is an excellent way of enhancing your diet by changing the way you eat without changing what you eat. There are several intermittent fasting methods, but they all follow the rule of a set time to fast and a set time to eat. These are generally called your fasting period and eating window.

It has been suggested through research that fasting can provide health benefits such as inflammation, blood pressure, and improvement in weight loss1.

When you follow an intermittent fasting regime, your body’s metabolism switches to burning fat to produce energy. You likely eat regular meals with snacks in between, providing your body with plenty of energy without having to burn any stored fat.

By going without food for a prolonged period, intermittent fasting encourages your body to tap into your fat storage more quickly and efficiently for energy. This is known as metabolic switching.

The Benefits Of Intermittent Fasting

While weight loss is a key component of why people start intermittent fasting, it is not always the primary purpose for most.

Fasting has been shown to provide promising health results. The other benefits of fasting include the following:

  • Lowering Cholesterol
  • Improving Glucose Control
  • Reduces Liver Fat
  • Disease Resistance
  • Improved Mental and Physical Performance

Why Is Water Important?

Your body’s major systems depend on water to function and survive. The human body can survive longer without food than without water.

About 60-70% of your body weight consists of water. A loss of just 4% of total body water leads to dehydration, and a loss of 15% can be fatal2.

Here are the reasons why water is such an essential element in your health:

  1. Regulates Body Temperature – your body loses water through sweat during physical activity and in hot environments. To maintain your body temperature, staying hydrated is crucial. Sweating is how your body keeps you cool, but your body temperature will rise if you don’t replenish the water you lose. This is because your body loses electrolytes and plasma when it’s dehydrated. If you’re losing fluids, it’s vital to increase your fluid intake so that you can restore your body’s natural hydration level.
  2. Removes Waste Products and Toxins – adequate water intake enables your body to excrete waste through perspiration, urination, and defecation. Water helps your kidneys remove waste from your blood and keep the blood vessels that run to your kidneys open and filter them out3.
  3. Protects Your Tissues, Spinal Cord, and Joints – water helps protect your spinal cord, and it acts as a lubricant and cushion for your joints. This will help you enjoy physical activity and lessen the discomfort caused by conditions like arthritis.
  4. Water Aids in Digestiondrinking water before, during, and after a meal will help your body break down the food you eat more efficiently4. This will help you digest food more effectively and get the most out of your meals.
  5. Improves Blood Oxygen Circulation – drinking water will help carry nutrients and oxygen to your entire body. Reaching your daily water intake will improve your circulation and have a positive impact on your overall health.

Why Is Water Important When Fasting?

The number one rule in intermittent fasting is not to consume any calories. As water contains no carbohydrates or calories, it is the perfect drink for intermittent fasting. Another fasting method known as dry fasting restricts water, but this is less commonly followed as it can lead to dehydration.

While fasting, you aren’t getting the nutrients from the food that gives your body energy. You will likely begin to feel sluggish, especially if you’re trying fasting for the first time. If you’re dehydrated, it can also cause fatigue and tiredness.

The only way to prevent dehydration is by drinking water. The more water you drink, the better you’ll feel.

Staying hydrated with water will also help balance your digestion and curb some of your hunger. When paired with fasting, drinking water can significantly help with cleaning waste from your body.

Water Fasting

Water fasting is much like intermittent fasting, but instead of simply restricting calories for a certain set of hours, water fasting limits all solid foods except water. Mostly, water fasts can last anywhere from 24 hours to 72 hours.

Though rare, it should be noted that you should not overdrink and risk water intoxication, which is called hyponatremia.

How Your Body Regulates Water

Water balance is achieved in the body by ensuring that the amount of water you consume in food and drink (and generated by metabolism) equals the amount of water excreted. On a typical day, the average adult consumes between 2-3 liters of water. The amount of water lost each day is similar in amount.

While almost a liter of water per day is lost through your skin, lungs, and feces, your kidneys are the major site of regulated excretion of water. Your kidney is your body’s greatest balancing act.

Its role is to regulate the amount of water in your body. If you happen to be dehydrated, your kidneys will conserve water, and your urine will be more concentrated. If you’re hydrated, your kidneys will produce a more dilute urine to rid your body of excess water.

To avoid dehydration, these are the ways through which you can detect when your body needs more water:

  • Thirst – your thirst is an automatic water level detection capacity of your brain. It is the signal that prompts you to crave water when you are running low on it.
  • Urine – most of the water you lose is through urine. When you have not drank enough fluids, your kidneys try to save as much water as they can and cause your urine to be darker in color (more concentrated). Dark yellow urine is a sign that you are dehydrated and that you must drink more fluids to prevent dehydration5.

How Much Water Should I Drink While Fasting?

Every metabolic reaction in your body leads to the loss of water. Other factors that increase your fluid needs include hot weather, high altitude, a high-fiber diet, and increased losses from caffeine and alcohol intake.

Any water loss needs to be replaced as often as possible for your body to keep functioning correctly. In general, men need at least 12 cups of fluid daily, while women require a minimum of 9 cups.

These days, most professionals in the nutrition and health industry agree that there is no need to have an exact figure attached to the amount of water that your body needs. It is believed that the brain mechanism that controls the need to rest and eat is strong enough to give you an accurate signal when your body requires a refill of water6.

However, when doing intermittent fasting, a well-hydrated body (meaning drinking more than the minimum amount) is an important key to a successful and safe fast. Experts recommend drinking at least 85 fl. oz (2.5 liters) daily.

Another way to determine the required amount is to drink according to your body weight. To help determine this, drink 0.5-1 fl. oz. per pound (30-40 milliliters per kilogram) of your body’s weight.

Can Water Help You Lose Weight?

If your fasting intent is to lose weight, you need to drink water not only for your health but also to lose weight successfully. Your body can mistake thirst for hunger, which can lead to increased intake if you are not mindful.

Water can help provide a feeling of fullness because water adds volume. Consistent fluid consumption may prevent you from snacking and taking extra portions.

Substituting water for higher-calorie beverages can also help decrease calories. Thus, drinking more water while fasting just might help you lose those extra pounds.

Kinds Of Water

  • Mineral Water – mineral water is one of the best drinks one can consume while fasting. Choosing mineral water over tap water is recommended. Mineral water is healthier than distilled or tap water because it contains naturally occurring minerals.
  • Sparkling Water/Carbonated Water – similar to mineral water, sparkling water also contains minerals and vitamins, restoring the mineral and electrolyte deficiency during fasting. Furthermore, the refreshing taste of sparkling water can help you feel rejuvenated.
  • Lemon Water – plain lemon water has no calories and will not break your fast. Additionally, lemon water has vitamin C, an antioxidant that fights free radicals and lowers inflammation.

What Drinks Won’t Break Your Fast?

It isn’t only water that’s acceptable to drink when intermittent fasting. You won’t need to limit yourself by drinking water since other liquids are also permitted.

  1. Black Coffee – coffee is another calorie-free drink and since the calorie count is basically none, there is no risk of breaking your fast. However, you shouldn’t drink multiple cups of coffee, especially while fasting, as the effect of the caffeine will be heightened by your empty stomach. According to research7, a small amount of caffeine could be beneficial to aid in burning fat during a fast. Just be sure to take black coffee not add sweeteners or cream.
  2. Tea – if you’re not a fan of black coffee, tea will become your best companion during moments of hunger in your fast. Tea also suppresses appetite and helps fight off unhealthy cravings. It will help you feel full, so you don’t mess up your limited eating period. Unsweetened tea is preferred, and the common types of tea consumed are green tea or black tea. Make sure you choose a tea that contains no added sugar, sweeteners, or additional ingredients such as artificial flavoring.
  3. Apple Cider Vinegar – diluting a small amount of apple cider vinegar in a cup of water won’t break your fast. Apple cider has been linked to other benefits complementing fasting as well such as supporting in weight loss and lower blood sugar.

What Should You Avoid Drinking During A Fast?

Avoid any drinks containing sugar or calories as these will break your fast. Try sticking to the drinks previously mentioned.

But if you do decide to drink the drinks listed below, if possible, only take them during your eating periods.

  • Soda
  • Energy Drinks
  • Fruit Juices
  • Gatorade
  • Sweetened Iced tea
  • Kombucha
  • Alcohol

Tips For Drinking More Water

You may find it challenging to drink enough water and that is pretty common even without fasting. To help you manage and drink enough water, here are some tips you can follow:

  • Bring a water bottle with you wherever you go. This way, you can drink whenever the need strikes.
  • Keep track of your intake. Aim to take in optimum amounts every day, a minimum of half your body weight in ounces.
  • Pace yourself to approach half of your recommended consumption by midday. You can always finish about an hour before you plan to sleep.
  • For some variety, add a few slices of cucumber, lemon, ginger, or a few leaves of mint.

Is Intermittent Fasting For Everyone?

Despite the benefits of intermittent fasting, it is not a practice that should be followed by everyone. If you fall into any of the following conditions, it is best that you do not start intermittent fasting:

  • Diabetes
  • Eating disorders (such as anorexia or bulimia nervosa)
  • Use of medications that require food intake
  • Active growth stage, such as in adolescents (children 18 and under)
  • Trying to conceive, pregnancy, breastfeeding

‍The Bottom Line

Keeping your body hydrated is imperative to your success in fasting. Ideally, you need to drink more water when you are fasting than when you’re not fasting, averaging between 2 to 3 liters a day.

You must ensure that, while fasting, your average water consumption is maintained to support your fast and prevent complications. Dehydration is one such complication while on a fast, and it can add extra symptoms if you are someone who feels the effects of fasting.

To add some flavors to your water, other drinks can also be consumed during fasting periods as long as they are low in calories and do not contain any sugar.


1 Samudera, W. S., Fernandez, G. V., Fitriyah, R., Arifin, H., Wulandari, S. M., & Permana, R. A. (2020). The Benefits of Fasting to Improve Health Conditions and to Prevent Cardiovascular Disease. Jurnal Ners, 14(3), 383–387. https://doi.org/10.20473/jn.v14i3.17168

2 Sargen, M. (2019, September 26). Biological Roles of Water: Why is water necessary for life?. Science in the News.

3 6 Tips To Be “Water Wise” for Healthy Kidneys. (2015, April 28). National Kidney Foundation Inc.. https://www.kidney.org/content/6-tips-be-water-wise-healthy-kidneys

4 Picco M.D., M. (n.d.). Healthy Lifestyle Nutrition and healthy eating. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/digestion/faq-20058348

5 Urine colour chart. (n.d.). NSW Government. https://www.health.nsw.gov.au/environment/beattheheat/Pages/urine-colour-chart.aspx

6 Brown, J. (2020, May 20). How much water should you drink a day?. BBC. https://www.bbc.com/future/article/20190403-how-much-water-should-you-drink-a-day

7 Vandenberghe C, St-Pierre V, Courchesne-Loyer A, Hennebelle M, Castellano CA, Cunnane SC. Caffeine intake increases plasma ketones: an acute metabolic study in humans. Can J Physiol Pharmacol. 2017 Apr;95(4):455-458. doi: 10.1139/cjpp-2016-0338. Epub 2016 Nov 25. PMID: 28177691.


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