Can you drink water while fasting

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Staying hydrated is the basic rule for keeping our bodies healthy to functioning, but you may be wondering, can you drink water while fasting? Yes! You can drink your purified water from a reverse osmosis system and not worry about an upcoming blood test or following a strict diet plan. 

Drinking purified water from a reverse osmosis system is a better way to purify your water than boiling it.

Intermittent fasting is a switch between steering away from food and certain drinks then eating regularly. It is also a technique to lose weight where you fast for a certain number of hours or eat one meal per day. One form of intermittent fasting is the 16/8 rule, where you eat for 8 hours and fast for 16. 

Fasting is also vital for medical procedures. It prevents your body from being affected by any foods you consume that may affect your insulin levels. 

But what are the drinks you can and cannot drink? Here is a quick guide to the does and don’ts of fasting.

How much water should I drink during intermittent fasting?

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It is safe to drink water while intermittent fasting because it does not affect blood sugar or insulin levels, and water has no calories. Only dry fasting is where you are not allowed to drink water. 

You can drink 8 ounces of water or more depending on your hydration levels during your fast since it is a clear liquid. However, Healthline notes that some medical professionals prohibit you from drinking 2 hours before a procedure.

Nonetheless, it is best to ask your doctor or the medical team for the exact guidelines for drinking water during fasting.

What drinks won’t break a fasting period?

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Other calorie-free drinks that won’t affect insulin levels are safe to consume during fasting aside from plain water. 

  • Black Coffee – You can drink coffee as long as it is calorie-free and can help increase your metabolism. Adding milk and sugar, however, can break your fast. But be careful with drinking too much coffee as caffeine can cause side effects such as jitters and irritability.
  • Unsweetened Tea – Tea is ultimately safe like coffee due to its calorie-free characteristics as long it is from tea leaves, bags, and flakes. Drinking bottled tea contains high levels of sugar, which breaks your fast.
  • Lemon Water – Lemon water is a highly regarded beverage for diet plans and contains low sugar, plus it is rich in antioxidants! Just make sure you are adding only natural flavors that contain no preservatives.
  • Sparkling Water – Carbonated water is naturally flavored and contains zero calories, implying it will not affect your metabolism. It also contains sodium and is quite acidic, so be careful with this. 

Special mention: Bone Broth – Some medical procedures may be lenient with bone broth, depending on the strictness of your diet. It does, however, contain some calories and fat. A small amount can be beneficial by providing minerals and vitamins. For intermittent fasting, however, bone broth is a no-drink.

Liquids to avoid during intermittent fasting

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Now that you know the drinks you can have during fasting, here are the beverages to stay clear from that have high levels of calories and sugar that can raise your blood glucose, completely breaking your fasting.

Apple Cider Vinegar

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A common misconception is that apple cider is a tonic you can consume during fasting. Because apple cider vinegar is made from apples, sugar, and yeast, it contains high amounts of calories that can increase your blood sugar. if consumed in large amounts.

However, if you just ingest small amounts, it is unlikely to negatively impact your fast.

empty stomach


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Alcohol contains heavy calories and can cause food cravings and hunger. Additionally, some alcoholic drinks may contain glucose, which will automatically break your fast plus, drinking alcohol on an empty stomach may not be the best idea.


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Soda, even diet soda, has heavy amounts of sugar and calories that offer no nutritional value, according to Women’s Health. It is also full of artificial sweeteners that can increase your appetite and food cravings. Aside from this, consuming too much soda encourages weight gain, hence being one of the top red flags for fasting.

Almond and Nut Milk

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Almond milk and nuts contain 30 – 80 calories per ounce. Although nut milks are generally low in carbohydrates, they do contain some glucose which can break your fasting plan. Additionally, Almond milk has high amounts of protein.


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Juice also contains high amounts of sugar and calories. Natural sweeteners like fruits, aside from lemons, are also considered to increase their sugar levels.

Coconut Water

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Although coconut is a refreshing beverage with many health benefits, it contains simple carbohydrates and high amounts of sugar that will immediately break your fasting.

Other mentions: The following also contain high glucose levels that can break your fasting.

  • Sports drinks
  • Kombucha and other sweet drinks
  • Lemonade
  • Smoothies
  • Energy drinks


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Aside from knowing what beverages you can and cannot drink during your fasting, here are some common questions you may be thinking

What happens when you drink water while fasting?

Drinking clear mineral water while fasting does not affect your sugar levels and helps your body function by allowing your blood to deliver oxygen to your organs.

Can you drink water while fasting for a glucose test?

If you’ve been wondering, can you drink water during fasting before a blood test? Definitely! Blood tests allow you to drink water since your body quickly digests it, and it makes collecting blood samples easier during the procedure.

However, you are not allowed to have any other drinks. Other medical institutions may require you to stop drinking water two hours before the blood test.

Consult your hospital or clinic regarding the guidelines for fasting to ensure you do not break it.


Now that you know the answer to whether can you drink water while fasting, you’re set to jot down your fasting plan. If you are doing intermittent fasting with a goal of weight loss, it’s best to seek the help of a professional to ensure it’s effective and you’re still receiving beneficial nutrients.

Read the nutrition facts panel before any fluid intake to ensure it contains no calories. Water may be the best and only exception in some fasting periods as it is easier for your digestive system to consume. Most of all, it’s a must to stay hydrated.


Benton, Emilia, and Ashley Martens. “Here’s Why You Can’t Drink Diet Drinks If You’re Doing Intermittent Fasting.” Women’s Health, 29 Nov. 2022,

Boyers, Lindsay. “What Can I Drink When Doing Intermittent Fasting? | Livestrong.” Livestrong, Leaf Group, 13 Nov. 2021,

“Fasting for a Blood Test: MedlinePlus Medical Test.” MedlinePlus, U.S. National Library of Medicine,

Link, Rachael. “Drinking Water While Fasting: Is It Recommended?” Healthline, Healthline Media, 22 Mar. 2021,

Quintero, Edibel. “Does Almond Milk Break a Fast?” HealthReporter, 14 July 2022,

Thomas, Wrona. “What Can You Drink during Intermittent Fasting?” Dr. Robert Kiltz, 30 June 2022,,will%20interrupt%20your%20fasted%20state.

“What Breaks a Fast: Everything You Need to Know.” Medical News Today, MediLexicon International,