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What Can You Drink During Intermittent Fasting?

"Nora Minno is an award-winning New York-based registered dietitian, certified dietitian nutritionist, and certified personal trainer specializing in wellness communications and marketing. For over ten years, she has consulted for several national publications and CPG companies, offering the latest advice in nutrition and fitness, and appears regularly on the Emmy-nominated Daily Burn 365 as well as the DailyBurn HIIT app."

Intermittent fasting has become a popular method for those looking to reap certain health benefits without having to count calories or follow a specific meal plan. IF allows for flexibility within your dietary choices, however, it’s important that you maintain your fasting state during your designated fasting windows. 

While the idea of not eating for a certain window of time might seem difficult, if you pick a plan that works for your lifestyle and sleep patterns, it may be easier than you think!

Also, with most popular plans allowing for certain beverages to be consumed during your fasting window, you can use drinks to stay hydrated and power through your fasting phase! 

When it comes to what you can and cannot drink while fasting, the general rule of thumb is:

  • Yes to zero-calorie and zero-sugar beverages
  • No to caloric and sweetened beverages.

Consuming beverages with sugars or even protein or fat, can evoke a metabolic response from your body and push it out of its fasting state. Therefore, it’s important to choose beverages that don’t contain carbohydrates, protein, or fat and are virtually calorie-free.

There are some people that choose to follow a dry fasting plan either for health or religious reasons, therefore beverages are not consumed during the fasting windows on these plans.

However, if you follow an intermittent fasting or time-restricted eating plan, such as the 16:8 plan, you can also use certain beverages to help you stay hydrated and power through your fasting window.

Below are some common questions when it comes to which beverages are allowed during the fasting period on an intermittent fasting plan.

Can you drink water during intermittent fasting?

Drinking water during your fasting window is not only allowed, but highly recommended! Since water is naturally calorie-free, it will not interrupt your body’s fasting state and it may even help manage feelings of hunger.

Staying adequately hydrated is important to support many functions of the body including:

  • General energy levels
  • Physical performance
  • Brain function[1]
  • Digestion[2]

Both plain and carbonated water can be consumed during your fasting window. If you opt for flavored seltzer water, just make sure that it is sugar-free and calorie-free.

Does lemon water break a fast?

We already know that water is a go when it comes to intermittent fasting, but plain water overtime can get boring. So, what about adding a little boost of flavor to your water with lemon juice?

Since natural lemon juice is very low in calories and contains about 0.3 grams of sugar per quarter lemon[3], most experts agree that lemon juice is ok to drink during your fasting period and will not interrupt your body’s fasting state.

It’s important to note that if you want to add lemon water to your fasting beverage rotation, you should use fresh-squeezed lemon juice to avoid any added sugars. It’s also important to stick with about 1/4 lemon per 8 fl oz of water to avoid consuming too many calories or sugar that may interfere with your fast.

Another fun way to add a hint of flavor to your water is by infusing it with other low/ no calorie vegetables and herbs such as:

  • Cucumbers
  • Lime
  • Basil
  • Mint

Can you drink coffee while fasting?

The moment all of you coffee-lovers have been waiting for: yes, you can drink coffee during your fasting period! A typical cup of black coffee[4] contains 2.4 calories and 0 grams of sugar per 8 fl oz, therefore it should not interrupt your fasting state.

It is important to note, however, that adding things like sugar, cream, or any calorie-containing syrups to your coffee could interrupt your fast, therefore it is recommended to drink your coffee black.

If you need a little sweetness or flavor in your coffee, but don’t want to interrupt your fast, you could try adding a no-calorie sweetener or calorie-free & sugar-free flavored syrup in small quantities.

 Can you drink tea while fasting?

Most brewed teas, such as green tea, are naturally calorie-free, therefore, they ok to drink during your fasting period.

As with coffee, if you add things like milk, honey, sugar, or cream, you could jeopardize your fasting state, therefore it is recommended to drink tea plain. If you need a hint of flavor, try adding in a squeeze of fresh lemon juice or make your own tea flavor by using a blend of different tea bags.

If you opt for iced tea over hot tea, especially one that is packaged, be sure to check the label to make sure you are choosing an unsweetened iced tea without added sugars or calories.

Does drinking diet soda break a fast?

Most diet sodas are free of calories and carbohydrates, therefore they should not interrupt your body’s fasting state.

While there is limited research regarding diet soda and intermittent fasting specifically, there is extensive research showing that aspartame, sucralose, and other non-nutritive sweetener consumption does not raise blood glucose or insulin levels.[5][6][7][8]

Before consuming a diet soda in your fasting state, be sure to check the nutrition facts panel to ensure that the soda is in fact calorie and sugar-free to ensure that you do not interrupt your fast.

Can you drink milk while fasting?

Milk, even skim milk, should be avoided during your fasting period.

All varieties of cow’s milk contain lactose, which is a naturally occurring sugar. As you know by now, it’s important to abstain from carbohydrates during your fasting period to avoid triggering a metabolic response in your body.

In addition to carbohydrates, milk also contains fat and protein, which can also push your body out of its fasting state by triggering a metabolic response.

There are several milk alternatives, such as almond milk, oat milk, and soy milk that do not contain lactose but may contain carbohydrates or calories from other macronutrients. If you absolutely need a little something for your coffee or tea, you could try adding in a small splash of unsweetened almond milk since it clocks in with the lowest calorie content of about 30 calories per 8 fl oz[9]. If you’re going for a stricter fasting plan, then it’s best to avoid all varieties of milk all together.

Does drinking apple cider vinegar break a fast?

If you have gotten used to drinking your morning shot of apple cider vinegar, then good news –  you can drink apple cider vinegar during your fasting window!

Apple cider vinegar is calorie-free and carbohydrate-free, therefore will not interrupt your fasting state.

Many have turned to drinking a daily dose of apple cider vinegar due to research suggesting that it may help improve blood sugar levels after a carbohydrate-rich meal[10][11] or for other reasons. While research on the effects of apple cider vinegar is limited, if you choose to consume apple cider vinegar daily, you can rest assured that it won’t interrupt your fast!

What about alcohol while intermittent fasting?

Alcoholic beverages, including wine, spirits, and beer all contain calories, therefore should be avoided during the fasting period.

If you choose to drink alcoholic beverages during your eating window, you should do so in moderation to help avoid dehydration and other negative effects that might occur as a result of overconsumption of alcohol. Remember, alcoholic beverages provide little to no nutritional benefit, therefore focusing on more nutrient-dense foods and beverages during your eating window can help you maximize the limited time you have to ensure that your body is getting adequate amounts of key nutrients.

Drinking during your eating window….

To boil it all down, there have been many benefits associated with intermittent fasting and time-restricted eating including weight loss[12], improved glucose sensitivity[13], and improved lipid profiles.

It’s important to keep your body in its fasting state during your fasting windows, so if you choose to drink during your fasting window, be sure to choose no or low-calorie beverages – there might be more options than you think!

Ok to Drink Avoid During Fasting Window
Water Milks or Creamers
Lemon Water Protein Shakes
Cucumber Water Sugar-Sweetened Sodas or Teas
Coffee (unsweetened) Juices
Tea (unsweetened) Smoothies
Apple Cider Vinegar Alcohol
Seltzer water (unsweetened) Sports Drinks
Flavored water (unsweetened)  

[1] Mild dehydration impairs cognitive performance and mood of men

[2] Constipation in older adults

[3] FoodData Central Search Results: Lemon Juice

[4] FoodData Central Search Results: Coffee, brewed

[5] Metabolic effects of aspartame in adulthood: A systematic review and meta-analysis of randomized clinical trials

[6] Aspartame Consumption for 12 Weeks Does Not Affect Glycemia, Appetite, or Body Weight of Healthy, Lean Adults in a Randomized Controlled Trial

[7] A 12-week randomized clinical trial investigating the potential for sucralose to affect glucose homeostasis 

[8] Glycemic impact of non-nutritive sweeteners: a systematic review and meta-analysis of randomized controlled trials

[9] FoodData Central Search Results: Almond milk, unsweetened, plain, shelf stable

[10] Vinegar consumption can attenuate postprandial glucose and insulin responses; a systematic review and meta-analysis of clinical trials

[11] Vinegar as a functional ingredient to improve postprandial glycemic control-human intervention findings and molecular mechanisms

[12] Impact of intermittent fasting on the lipid profile: Assessment associated with diet and weight loss

[13] Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes

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