During intermittent fasting, the simplest drinks are water, black coffee, and unsweetened tea.[1] Sparkling water or seltzer can also be a low-calorie option when it has no sugar or meaningful calories.[2]
Drinks with sugar, milk, cream, juice, alcohol, protein, collagen, MCT oil, or other calorie-containing add-ins belong in the eating window.
Key takeaways
- Water is the simplest fasting-window drink because it has no calories.[2]
- Black coffee and unsweetened tea are common fasting-window options.[1]
- Sweetened drinks, juice, smoothies, alcohol, milk, cream, and protein drinks belong in the eating window.
- Diet drinks may have few or no calories, but they should not be framed as the strongest fasting default.[3][4]
- If fasting causes dizziness, dehydration symptoms, medication conflicts, or feeling unwell, stop or adjust the plan and get guidance when needed.[5]
Table of Contents
Fasting-window drink list
| Drink | During a clean fast? | Practical note |
|---|---|---|
| Plain water | Yes | Strongest default |
| Sparkling water or seltzer | Usually yes | Choose no sugar and no meaningful calories |
| Black coffee | Usually yes | Keep it unsweetened |
| Unsweetened tea | Usually yes | Hot or iced is fine if unsweetened |
| Lemon water | Depends | A small squeeze is different from lemonade; keep it minimal if you use it |
| Diet soda | Depends on your rules | Not the strongest everyday default |
| Coffee with milk or cream | No for a clean fast | Use during the eating window |
| Juice or smoothies | No | Treat as eating-window drinks |
| Alcohol | No | Do not use as a fasting-window drink |
| Protein shakes | No | Treat as food or a meal component |
If you want the clearest fasting boundary, choose water first.
Coffee and tea during intermittent fasting
Black coffee and unsweetened tea can fit many fasting routines.[1] The boundary changes when you add calories or sweetness.
Keep in the fasting window:
- Black coffee
- Plain espresso
- Unsweetened black tea, green tea, herbal tea, or iced tea
Move to the eating window:
- Lattes and cappuccinos
- Coffee with cream, milk, sugar, honey, syrups, collagen, or MCT oil
- Sweet tea
- Bottled tea with added sugar
If coffee makes you jittery, worsens reflux, or triggers urgent digestion, reduce it or keep it inside the eating window.
What about diet drinks and sweeteners?
Non-sugar sweeteners may add few or no calories and generally do not raise blood sugar levels, but that does not automatically make every diet drink helpful for fasting.[4] Sweet taste may also make the routine harder for some people if it increases cravings or snacking.
A practical hierarchy:
- Water
- Unsweetened tea or black coffee
- Unsweetened sparkling water
- Diet drinks only if they help you stay consistent and do not trigger more cravings
Check labels instead of relying only on a "diet" or "sugar-free" claim.
Drinks to keep in the eating window
Keep these drinks inside the eating window because they contain calories, sugar, alcohol, protein, or meal-like ingredients:
- Juice
- Smoothies
- Soda and sweet tea
- Sports drinks and many energy drinks
- Alcohol
- Milk or sweetened plant milks
- Protein shakes
- Bone broth, if your fasting rules define calories as breaking the fast
- Coffee with cream, milk, sugar, collagen, MCT oil, or syrups
Sugary drinks can add calories without making meals more filling. Replacing sugary drinks with plain water can help reduce calorie intake.[2]
How GoFasting can support drink consistency
GoFasting can help you log fasting windows and water intake, then review patterns as you adjust your routine. That can be useful if your fasting window looks fine on paper but your water intake is low.
Tracking can support consistency, but it does not determine whether fasting is medically appropriate.
If food or drink choices are the harder part of the routine, these connected questions can help: What other drinks can you drink?.
FAQ
Can you drink during intermittent fasting?
Yes. You can drink during fasting, but for a clean fast, keep drinks to water, black coffee, or unsweetened tea.[1]
What can I drink while intermittent fasting?
Water, sparkling water without sugar or meaningful calories, black coffee, and unsweetened tea are the simplest options. For more food and drink context, read What can I eat while intermittent fasting?.
Does lemon water break a fast?
A small squeeze of lemon in water is different from lemonade. If you want the cleanest fasting window, choose plain water. If lemon water helps you drink more and contains minimal calories, decide based on your fasting rules.
Can I drink diet soda while intermittent fasting?
Diet soda may have few or no calories, but it is not the strongest default drink. If it increases cravings or makes fasting harder, choose water, black coffee, or unsweetened tea instead.[4]
Can I drink alcohol while intermittent fasting?
Alcohol belongs in the eating window, not the fasting window. It may also be harder to tolerate without food and can work against hydration and routine consistency.
Bottom line
The clearest fasting-window drinks are water, black coffee, and unsweetened tea. Keep calorie-containing drinks, sweetened drinks, alcohol, protein drinks, and creamy coffee in the eating window. When in doubt, choose water and keep the routine simple.
Medical disclaimer
This article is for general educational purposes only and is not medical advice. Talk with a qualified health care professional before starting intermittent fasting if you have a medical condition, take medications, are pregnant or breastfeeding, are underweight, have a history of an eating disorder, or feel unwell while fasting.
References
- Johns Hopkins Medicine. Intermittent Fasting: What Is It, And How Does It Work? https://www.hopkinsmedicine.org/health/expert-qa/intermittent-fasting-what-is-it-and-how-does-it-work
- CDC. About Water and Healthier Drinks https://www.cdc.gov/healthy-weight-growth/water-healthy-drinks/index.html
- Harvard T.H. Chan School of Public Health. Healthy Drinks https://nutritionsource.hsph.harvard.edu/healthy-drinks/
- FDA. Aspartame and Other Sweeteners in Food https://www.fda.gov/food/food-additives-petitions/aspartame-and-other-sweeteners-food
- Cleveland Clinic. 6 Tips for Fasting Safely https://health.clevelandclinic.org/tips-for-fasting-the-healthy-way