Intermittent fasting works when you eat during specific time windows and fast during others. During your fasting window, you can drink certain beverages that won’t break your fast, and you can drink anything you want during your eating window. This guide tells you exactly what you can drink and when.
What happens to your body during fasting?
When you fast, your body shifts from burning glucose to burning fat for energy. This process starts about 12 hours after your last meal. Your body also increases human growth hormone levels and begins autophagy, where cells clean out damaged parts. Drinking the wrong beverages during your fasting window stops these processes.
Can you drink water during intermittent fasting?
Yes. Water is the best drink during fasting. You can drink as much plain water as you want during your fasting window. Still water and sparkling water both work. Water keeps you hydrated without adding calories or spiking insulin. Studies show that drinking cold water burns about 8 extra calories per glass because your body uses energy to heat the water to body temperature.
Most people should drink 8 to 12 glasses of water per day. Use your thirst as a guide, but drink extra water during your fasting window since thirst sometimes gets confused with hunger.
Can you drink black coffee while fasting?
Yes. Black coffee contains almost zero calories and won’t break your fast. Coffee also increases fat burning and reduces hunger. Studies show that caffeine boosts metabolism by 3 to 11 percent and increases fat burning by up to 29 percent.
Drink coffee without adding sugar, milk, cream, or artificial sweeteners. These additions add calories and spike insulin, which breaks your fast. If you need flavor, add a small amount of cinnamon.
Can you drink tea during intermittent fasting?
Yes. Plain tea works the same as black coffee. Green tea, black tea, white tea, oolong tea, and herbal tea all work during fasting windows. Like coffee, tea contains compounds that boost metabolism and reduce hunger.
Green tea contains catechins that increase fat burning. Studies show green tea extract increases energy expenditure by about 4 percent, though the effect is small. Drink tea without sugar, honey, milk, or artificial sweeteners.
Can you drink diet soda or zero-calorie drinks while fasting?
This one gets tricky. Diet sodas and drinks with artificial sweeteners technically contain zero calories, but they may still spike insulin in some people. When insulin rises, your body stops burning fat and exits the fasted state.
The research remains mixed. Some studies show artificial sweeteners don’t affect blood sugar or insulin, while others show they do. Individual responses vary based on genetics and gut bacteria.
If fat loss is your main goal, skip diet sodas during your fasting window. If you must have them, test your response by checking your blood glucose before and after drinking diet soda. If your glucose stays stable, diet drinks probably won’t break your fast for you.
What about bone broth during fasting?
Bone broth contains calories and protein, which means it breaks a true fast. One cup of bone broth has about 40 to 50 calories. This triggers an insulin response and stops autophagy.
Some people practice modified fasting where they consume up to 50 calories during the fasting window. This approach still provides some fasting benefits, though not as many as a strict water fast. If you struggle with hunger, bone broth can help you stick to your fasting schedule.
Can you drink lemon water while fasting?
Yes, if you use it correctly. Adding a squeeze of fresh lemon to water is fine. Half a lemon contains only 6 calories, which won’t significantly affect your fast. Lemon water can reduce hunger and add flavor to plain water.
Don’t add sweeteners to lemon water. Skip honey, sugar, and artificial sweeteners. The citric acid in lemons may also boost fat burning slightly, though this effect is minimal.
What about apple cider vinegar during fasting?
Yes, in small amounts. One tablespoon of apple cider vinegar contains only 3 calories. Mix it with water and drink it during your fasting window. Apple cider vinegar helps control blood sugar and reduces hunger.
Studies show that consuming vinegar with meals lowers blood sugar spikes by 20 to 40 percent. While research hasn’t tested this effect during fasting specifically, the low calorie content means it likely won’t break your fast.
Can you drink alcohol while intermittent fasting?
Alcohol breaks your fast. Even though spirits like vodka and whiskey contain zero carbs, they contain calories and your body prioritizes burning alcohol before fat. Alcohol also stops autophagy and other fasting benefits.
Save all alcoholic drinks for your eating window. Beer, wine, and mixed drinks all contain calories and will break your fast immediately.
What drinks should you avoid during fasting?
Never drink these during your fasting window:
1. Regular soda and sweetened drinks
2. Fruit juice
3. Smoothies
4. Milk and non-dairy milk alternatives
5. Protein shakes
6. Sports drinks
7. Energy drinks with calories
8. Flavored coffee drinks
9. Bubble tea
10. Sweetened tea
All of these contain calories, spike insulin, or both. They immediately stop fat burning and end your fasted state.
How do different drinks affect insulin?
Insulin is the hormone that stops fat burning. When you eat or drink calories, insulin rises. Here’s how different drinks affect insulin:
Water: Zero effect on insulin
Black coffee: Minimal to zero effect
Plain tea: Minimal to zero effect
Diet drinks: May spike insulin in some people
Lemon water: Minimal effect
Apple cider vinegar: May lower insulin response to meals
Bone broth: Moderate insulin spike
Protein shakes: Large insulin spike
Fruit juice: Very large insulin spike
What can you drink during your eating window?
During your eating window, drink anything you want. This includes all the drinks banned during fasting plus nutritious options like:
1. Whole milk or plant-based milk
2. Fresh vegetable juice
3. Protein shakes
4. Smoothies with whole fruits and vegetables
5. Kefir or kombucha
Focus on drinks that support your nutrition goals. Whole food smoothies with protein and healthy fats keep you full longer.
Does the type of intermittent fasting change what you can drink?
The basic rules stay the same across all fasting protocols. Whether you follow 16:8, 18:6, 20:4, or alternate day fasting, stick to zero-calorie drinks during fasting windows. The longer you fast, the more important it becomes to avoid anything that might break your fast.
During extended fasts of 24 hours or more, you may need to add electrolytes to your water. This prevents headaches, fatigue, and muscle cramps.
What about adding electrolytes to water?
Yes, but choose carefully. Plain electrolyte powders without sweeteners or flavors work during fasting. Look for products with just sodium, potassium, and magnesium. These minerals don’t contain calories and help you stay hydrated.
Avoid electrolyte drinks with added sugars, artificial sweeteners, or calories. Most commercial sports drinks contain too much sugar to use during fasting.
How much caffeine can you have while fasting?
Most people can safely consume up to 400 milligrams of caffeine per day. That equals about 4 cups of coffee. Spread your caffeine intake throughout the day rather than drinking it all at once.
Too much caffeine causes jitters, anxiety, and sleep problems. Start with less if you’re sensitive to caffeine. The appetite-suppressing effects of caffeine work best when you drink it during your fasting window.
Can drinks help reduce fasting hunger?
Yes. Certain drinks reduce hunger during fasting:
Sparkling water creates a feeling of fullness
Coffee and tea suppress appetite naturally
Cold water takes longer for your stomach to empty
Apple cider vinegar helps control blood sugar
Drink these when hunger hits during your fasting window. Most hunger pangs during fasting are mild and pass within 15 to 20 minutes.
FAQ: Common questions about fasting drinks
Does coffee with MCT oil break a fast?
Yes. MCT oil contains calories and stops autophagy, though it may not spike insulin much. Save it for your eating window.
Can I drink kombucha while fasting?
No. Kombucha contains calories from the fermentation process. One cup has about 30 to 50 calories.
What about flavored sparkling water?
Check the label. Natural flavors without calories or sweeteners are fine. Avoid versions with added sugars or artificial sweeteners.
Does chewing gum break a fast?
Most gum contains sugar or artificial sweeteners that may break your fast. Skip it during fasting windows.
Can I drink bulletproof coffee while fasting?
No. Bulletproof coffee contains butter and MCT oil, which add hundreds of calories. This breaks your fast completely.
Will drinking too much water break my fast?
No. You can’t break a fast by drinking too much plain water, though drinking excessive amounts in a short time can be dangerous.
Can I drink coconut water during fasting?
No. Coconut water contains natural sugars and calories that break your fast.
Does cream in coffee break a fast?
Yes. Even a small amount of cream contains calories and fat that trigger an insulin response.
The simple rule for fasting drinks
Stick to water, black coffee, and plain tea during your fasting window. Everything else either breaks your fast or might break your fast depending on your individual response. When your eating window opens, drink whatever supports your health goals.
The drinks you choose during fasting make the difference between struggling through hunger and sailing through your fast with energy. Water forms the foundation, coffee and tea add variety and appetite control, and that’s all you need for successful intermittent fasting.
