What Can I Drink While Fasting?
Video | Water | Carbonated Water | No-calorie Sweetened Water | Lemon Water | Coconut Water | Coffee & Tea | Cream, Milk, Half-and-Half | Coffee Fats (Coconut Oil, MCT Oil, Butter, Ghee) | Coffee Sweeteners (Honey, Agave, Sugar & Substitutes) | Diet Soda & Energy Drinks | ACV | Bone Broth
When you fast, you don’t eat. But can you drink? And if so, what can you drink while fasting? In this blog post, we’ll go over which drinks get the green light, which ones get the red light, and the ones that fall in between.
What Can You Drink While Fasting? Summary
What Can I Drink While Fasting? [Video]
In this video, you’ll learn…
- Which drinks you are allowed to drink freely during a fast!
- Drinks that you should drink only in moderation.
- Drinks that you should avoid while fasting and/or trying to lose weight.
Let’s start with water. Should you drink water while fasting? Yes. With no calories or nutrients to break your fast, plain water not only gets the green light but also supports your body and metabolism during your fasting hours.
What if the water you drink has carbonation added? Unsweetened carbonated waters also get the green light. In fact, you may find that bubbly waters, like sparkling water, club soda, mineral water, or seltzer, provide a bit of variety and enjoyment during your fast.
Sweetened Waters (Non-Caloric Sweeteners)
If your plain or carbonated water is sweetened with a non-calorie sweetener, you’ll want to take a step back and apply caution. Some non-caloric sweeteners have a glycemic index, which means that even though they don’t contain sugar, they cause your blood sugar to rise.
Studies have also linked these substances to altered gut health, glucose intolerance, and insulin resistance, which are all issues that can impact your ability to lose weight (1)(2).
Not all sugar substitutes are created equal. If you choose to consume one during your fast, you are best off going with naturally derived choices like stevia or monk fruit.
If you’re looking to jazz up your water in a more natural way, you may be wondering about adding lemon juice to your water. This gets the green light. While it will add a few calories, it is doubtful that a squeeze of lemon juice is enough to destroy the benefits gained over hours of fasting.
Lemon is a fruit, and so is coconut. So, is coconut water ok to drink while fasting? No. The reason has to do with the macronutrient content of coconut water. A cup of unsweetened coconut water has less than a gram of fat and more than 9 grams of carbohydrates. The natural sugars in coconut water make it off-limits during your fasting hours.
Don’t get coconut water confused with coconut oil. As we delve into coffee and tea, we’ll touch on that oil, which is pure fat.
Black Coffee & Tea
If you are a coffee or tea lover, you’ll be happy to know that both get the green light making them ok to consume during your fasting window. However, you may be surprised to learn that coffee and tea are not completely free of calories or carbs. Plants make carbohydrates through photosynthesis, so all plant foods contain carbs.
Coffee and tea are drinks that we get by brewing parts of plants, namely coffee beans, and tea leaves. During the brewing process, small particles make it into your cup. Therefore, a single 8-ounce cup of black coffee could contain a gram of carbohydrate.
So, how can coffee and tea be ok?
For one thing, any trace carbs that make it into your cup tend to be in the form of fiber, so their impact on your blood sugar is negligible. Also, coffee has been shown to support fat loss. It could be that the nutrients in the coffee combine with the metabolic boost that you get from the caffeine to give you the fat-burning advantage.
Long story short, feel free to pour yourself a cup of coffee or tea to pass the time during your fast.
If a plain cup of black coffee or tea doesn’t thrill you, you’re likely wondering what, if anything, you can add.
Cream, Half-and-Half, Milk
The most popular coffee or tea add-ins are cream, half-and-half, and milk. These ingredients get the green light, but just barely. It’s like getting to the intersection just as the light is switching from green to yellow. You’ll make it through, but if you try to push it, you’ll be in trouble. In other words, during your fast, you can enjoy one serving of these add-ins without noticeable consequences.
However, each of them contains calories, and calories are energy. Your body will use those easily accessed calories before returning to the less accessible calories stored in your fat cells. Therefore, if you are drinking three cups of coffee in the morning and adding cream, half-and-half, or milk to each cup, your calories are creeping up to a level that matches your body’s energy needs.
Cream, or heavy cream, is a better choice than milk or half-and-half because it consists primarily of fat. Dietary fat has little impact on your blood sugar and insulin level, so consuming fat calories during your fasting period will not knock your body out of fat-burning mode.
Milk (including plant-based milk such as hemp or almond milk) contains a mix of fat, protein, and carbohydrates, which gives it more potential to break a fast. If milk is your preferred add-in, you’ll be happiest with your results if you use full-fat milk rather than skim or low-fat milk.
Half and half is a mix of cream and milk, so its impact on your blood sugar will fall between that seen with cream and milk. It still provides calories that your body will use, but one serving will not wipe out the benefits gained during a fast that lasts 16 hours or so.
My husband, Keith, and I put half and half to the test by measuring our blood sugar and ketone readings after drinking it. I will point to the half-and-half blog post if you’d like to see those results.
Coffee Fats (Coconut Oil, MCT Oil, Butter, Ghee)
We know that mostly pure fats, like cream, do not significantly raise your blood sugar and insulin levels. Because of this, we say that they do not move your body out of fat-burning mode.
Insulin is somewhat of a gatekeeper. Its job is to move nutrients into storage. So when you consume nutrients, insulin moves them out of your blood and into cells that can use them or cells that can store them. In other words, when insulin is high, conditions are suitable for nutrient storage, including fat storage. When it is low, you are in fat-burning mode.
The understanding that dietary fat does not knock you out of fat-burning mode is important to those who practice intermittent fasting. This is why you see people adding pure fats, like coconut oil, MCT oil, butter, and ghee, into their coffee to make “bulletproof coffee” style concoctions. These pure fats are handled the same way as cream.
A single serving gets the green light, but get ready to apply the brake.
If you are having multiple cups of coffee and, therefore, multiple servings of fat, your body will use those easily accessed calories before returning to the less accessible calories stored in your fat cells, stalling weight loss.
Coffee Sweeteners: Honey & Agave
If sweetness is what you’d like in your coffee or tea, you may be wondering if honey or agave syrup is an acceptable add-in during your fast. No. These sweeteners get the red light. Agave nectar or agave syrup contains a high amount of fructose, which is a type of sugar that is metabolized by your liver and easily turned into fat.
Fructose is the same natural sugar found in fruit. However, unlike fruit, agave doesn’t have fiber to balance the absorption of fructose. So, even though agave is natural sugar, it should be avoided.
Raw honey contains some beneficial compounds, but it is also high in fructose. While the decision to use honey is up to the individual, you’ll be happiest with your results if you avoid honey during your fasting period.
Coffee Sweeteners: Sugar & Sugar Substitutes
Adding sugar to your coffee will sweeten it but get the red light when fasting. In fact, this is a habit to avoid at any time of the day.
As I mentioned earlier, sugar substitutes get the yellow caution light. It can be argued that not all non-caloric sweeteners are created equal. I would concur that stevia, monk fruit, and others that are derived from natural substances are better options than artificial sweeteners, like Splenda, Equal, and Sweet-n-Low.
However, beyond the debate over their health value, there is one overarching reason why I recommend reducing or eliminating all sugar substitutes from your diet. That reason is that their intense sweetness keeps your addiction to sweets alive. Sugar-free beverages are still sweet. If you continually consume them, you constantly feed your sweet tooth, making it much easier to slip back into poor eating habits.
Diet Soda & Sugar-Free Energy Drinks
We’ve already made a case for avoiding drinks sweetened with sugar. Diet sodas and sugar-free energy drinks are not healthy alternatives. These non-caloric drinks contain many additives and are sweetened with artificial sweeteners tied to health issues, like insulin resistance and thyroid problems.
However, we’ll give them the yellow caution light for this reason: If they help you break your sugar habit, they can be used as a temporary stepping stone to ending your addiction. Just keep in mind that you’ll be happiest with your overall health results if you wean yourself off of these diet drinks.
Apple cider vinegar has been touted as a natural remedy for everything from better health to weight loss, and there is scientific evidence to support many of these claims (3).
Because of its many benefits and the fact that it is free of calories, apple cider vinegar diluted in a glass of water gets the green light. It is acceptable to take it during your fasting window or right before a meal. Some people also claim that taking it during their fast helps control hunger.
Bone broth is rich in amino acids, which are the building blocks of protein. Consuming protein will disrupt your fast. However, I’ll give bone broth the yellow, proceed with caution light.
If you are just getting started with intermittent fasting and feeling fatigued or hungry, bone broth can support you as you work toward becoming more comfortable with your new eating schedule.
Also, while fasts lasting longer than a day should only be done under your doctor’s supervision, bone broth may help protect muscle mass and control hunger during a prolonged fast, thanks to its high protein content.
Remember that fasting is effective for weight loss because it robs your body of easy energy, forcing it to tap into harder-to-access body fat. Fasting also has benefits beyond weight loss. Consuming calories during your fast may interrupt certain healing processes, like autophagy.
Therefore, if you are looking to use fasting for health benefits as well as weight loss, you will be happiest with your results if you stick with our green light drinks, which include plain or carbonated water, with or without a wedge of lemon, water mixed with apple cider vinegar, and plain coffee or tea.
If you are curious about what is happening inside your body during a day of fasting, you can download my fasting effects timeline. Having this timeline handy will act as a great motivator as your progress with your fasting lifestyle.
Thank you for reading and have a wonderful week!
(1) Suez, Jotham, et al. “Non-caloric artificial sweeteners and the microbiome: findings and challenges.” Gut microbes 6.2 (2015): 149-155.
(2) Ruiz-Ojeda, Francisco Javier, et al. “Effects of sweeteners on the gut microbiota: a review of experimental studies and clinical trials.” Advances in nutrition 10.suppl_1 (2019): S31-S48.
(3) Mitrou, Panayota, et al. “Vinegar consumption increases insulin-stimulated glucose uptake by the forearm muscle in humans with type 2 diabetes.” Journal of diabetes research 2015 (2015).
About the Author
Becky Gillaspy, DC, is the author of The Intermittent Fasting Guide and Cookbook. She graduated Summa Cum Laude with research honors from Palmer College of Chiropractic in 1991.