Can You Drink Water While Fasting?

Short-term fasting has a long history in many cultures, whether because of religious beliefs or because the food was not always available. In the past few decades, fasting has become a popular way to lose weight, boost brain health, and slow down the aging process.

Key takeaways:

People restrict whole foods while fasting, but many questions remain about drinks. For example, can you drink water while fasting? If so, which drinks are allowed and which aren’t?

What is fasting?

Fasting is intentional food abstinence. However, fasting options differ. Water fasting means no foods are consumed during a 24 to 48-hour period. While intermittent fasting, you eat during a feeding window (while maintaining a regular diet) and fast for the rest of the time — 16:8 (16 hours fasting, 8 hours feeding time) is a popular choice. Some may choose to eat every other day or practice 5:2 fasting when they eat as usual for five days and limit their caloric intake for the other two days. “Fat” fasting allows water and pure fatty foods like coconut oil or MCT oil. Dry or absolute fasting restricts both food and liquid. A healthcare professional can help you choose the best type of fasting method to help you meet your health goals.

Can I drink water when intermittent fasting?

You can and should drink water while intermittent fasting. However, you avoid foods and drinking water only while dry fasting.

Those who practice fasting typically need more than the recommended daily water intake of two liters. This is because about one-fifth of water consumption comes from foods like fruits and vegetables, and people who fast eat fewer foods.

Studies on water fasting and intermittent fasting found that these practices promote many benefits. Here is a brief overview of water fasting: it promotes healthy body weight and may help slow the aging process. Furthermore, experts say that they also boost brain and heart health, promote healthy blood sugar levels, reduce inflammation, and may help prevent cancer.

During the Muslim holiday Ramadan, people do not eat or drink from sunrise to sunset for one month but are allowed to eat and drink outside the fasting period.

Can I drink water when taking blood tests?

Doctors recommend eating or taking some medications between 8-12 hours before a fasting blood test, including a fasting glucose test. However, you are free to drink water during the fasting period.

Doctors may recommend that you stop drinking water for some time (i.e., a couple of hours) before a medical procedure or surgery.

What can I drink when fasting?

It depends on the type of fast. Here is a brief overview of what you can drink when fasting. Strict water fasting means that you cannot have anything else other than water while fasting. Some other fasting methods allow plain coffee, tea, zero-carb flavored water, or vitamin water.

Water drinks

Lemon water

Lemon water is safe during fasting. In addition to staying hydrated, lemon water also contains some nutrients like vitamin C and small amounts of B vitamins, potassium, and iron.

Sparkling water

Like regular water, sparkling water is also a great choice while fasting. Man-made sparkling water is infused with carbon dioxide (seltzer water) or occurs naturally in mineral springs. Sparkling water contains essential minerals like magnesium, calcium, and potassium.

Flavored water

There are many options available in stores. Products like Zevia are sweetened with stevia, a natural, zero-carb alternative to sugar, which does not spike insulin levels. Brands like Bubbly offer unsweetened flavored sparkling waters. Flavored seltzer water is also popular and can be enjoyed while fasting. However, flavored water with added sugar should be avoided.

Vitamin water

Most formulas contain sugar and, therefore, should be avoided. However, consuming zero-carb versions during a fast is permitted.


The most common forms of fasting allow water, plain tea, and coffee. So-called “fat” fasting allows fats, as pure fats do not break the fast. However, drinks containing carbohydrates and protein are generally avoided while fasting because they break the fast.


Drinking tea (and caffeinated coffee) could help maintain the fast, as they reduce the appetite. Enjoy plain tea or sweetened with stevia.


Black coffee, coffee sweetened with stevia, or coffee flavored with cinnamon or cardamom are safe. On the other hand, drinks with sugar, maple syrup, honey, agave, milk, and alternative dairy products should be avoided during fasting. The “Bulletproof coffee” has added fats like coconut oil or MCT oil and can be consumed by those who practice “fat” fasting.

Other drinks

Drinks that contain carbs or proteins like coconut water, juices, hot chocolate, or alcoholic beverages like beer and wine will break a fast; thus, they should be all avoided while fasting.

Protein drinks

While carbohydrates are best known for breaking a fast, proteins can do so, also.

Protein shakes should not be consumed while water fasting. If you practice intermittent fasting, you cannot drink protein shakes during the fasting window, but they can be safely consumed along with other protein-rich foods as part of a healthy diet. Proteins are made of amino acids, and some supplements contain one or multiple amino acids. Some amino acids and related compounds like beta-alanine, betaine, D-aspartic acid, carnitine, and creatine can be consumed during fasting. On the other hand, branched-chain amino acids (BCAA) should not. Foods high in BCAAs include soy products, corn, chicken, baked beans, and lentils.

What drinks to avoid when fasting?

When on a strict water fast, you should drink only water — plain water, sparkling water, or zero-carb water with electrolytes. Some water fasts also include flavored water with lemon or peppermint leaves. Zero-calorie, zero-carb flavored drinks sweetened with stevia and sugar-free vitamin water are also good options. Aim for two liters of water or more every day.

All other drinks like protein shakes, milk (and its vegan alternatives), smoothies, alcoholic beverages, juices, or any drink that contain calories from carbohydrates and proteins should be avoided because they break the fast.

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