When Intermittent Fasting, What Can I Drink? Full List

Plain water, sparkling water, black coffee and unsweetened tea keep an intermittent fast going on any schedule. They have between 0 and about 2 calories a cup and no sugar. The harder part of what you can drink when intermittent fasting is everything else. Sweeteners, milk, lemon, broth and “healthy” bottled drinks each sit somewhere between safe and fast-breaking, and the answer can change with your goal.

When intermittent fasting, what can I drink?

Intermittent fasting limits food, and water is allowed on every schedule from 12:12 to one meal a day. Still water, tap water and plain sparkling water have no calories. Soda water and club soda are the same. Tonic water is a different drink, with about 34 calories and 9 g of sugar per 100 ml. A 330 ml bottle has about 112 calories.

Plain tea comes next. A 240 ml (8 fl oz) mug of black, green or herbal tea comes to roughly 2 calories. A cup of black tea has about 47 mg of caffeine and green tea about 28 mg, while chamomile and other herbal teas have none. Oolong and white tea brewed plain belong with black and green tea. Plain matcha whisked into water counts as green tea.

Fruit, hibiscus and other herbal blends count as herbal tea when they are a plain infusion. Some blends add dried fruit or sugar, so check the ingredients. Chai is spiced black tea, so count any milk and sugar added to it.

Black coffee comes to about 2 calories a cup, and most fasts stay intact with it. Milk, sweeteners and bulletproof coffee each change that, as the coffee and add-ins guide shows item by item.

How the drinks compare for each fasting goal

Why you fast changes the verdict. The site sorts every drink by four goals: blood sugar, weight loss, gut rest and autophagy. That framework is this site’s own, with no medical body behind it. The weight-loss verdicts lean on a rule of thumb, though no health body has made it official. On that rule, a drink below about 50 calories leaves a weight-loss fast intact.

Drink and serving	kcal	Weight-loss goal	Autophagy goal	Gut-rest goal	Blood-sugar goal
Sparkling water	0	Safe	Safe	Safe	Safe
Herbal tea (240 ml)	about 2	Safe	Safe	Safe	Safe
Black or green tea (240 ml)	about 2	Safe	Safe	Safe	Safe
Diet cola (330 ml can)	about 7	Grey	Grey	Grey	Grey
Lemon water (juice of 1 wedge)	about 1	Safe	Grey	Safe	Safe
Apple cider vinegar (1 tbsp in water)	about 3	Safe	Grey	Grey	Safe
Unsweetened almond milk (240 ml cup)	about 40	Grey	Breaks	Grey	Grey
Bone broth (240 ml)	often about 40	Grey	Breaks	Breaks	Safe
Kombucha (240 ml)	40 to 60	Grey	Breaks	Breaks	Breaks
Coconut water (240 ml)	about 45	Grey	Breaks	Breaks	Breaks

Plain black, green and herbal tea are all marked safe for all four goals. Bone broth varies by brand, from about 15 to over 100 calories a cup.

Diet drinks, lemon water and other grey areas

Diet cola has about 2 calories per 100 ml, so a 330 ml can of diet soda or Coke Zero has about 7. Nobody has settled whether its sweeteners nudge insulin, and the effect may differ from person to person. Seven calories barely registers on a weight-loss fast. Even so, the site gives diet drinks a grey verdict on every goal, since the drink is sweet. The World Health Organization’s 2023 guideline also recommends against non-sugar sweeteners as a way to manage weight, a conditional recommendation. Some people find sweet tastes make them hungrier, but the research on that is mixed.

Zero-sugar energy drinks follow the same sweetener logic, with caffeine on top. Count that caffeine towards the 400 mg a day that is safe for healthy adults. Flavoured “zero” waters with no sugar and no sweetener on the label are safe for every goal. A sweetener makes them grey, the same as diet cola.

The juice of one lemon wedge has about 1 calorie, and half a lemon has about 5. A tablespoon of apple cider vinegar has about 3. Both are acidic, and acidic drinks can wear tooth enamel. Drink them with meals or through a straw, and don’t brush straight afterwards.

Jeera (cumin) water is made by soaking cumin seeds and straining them out. A teaspoon of the seeds has about 8 calories if you eat them, and the strained water has less. No measured figure exists for the drink itself. The weight-loss and “detox” claims made for jeera water are not established.

Drinks that break a fast

Drinks with sugar, a lot of milk, protein or alcohol break a fast. These common ones are all well over the 50-calorie rule of thumb.

Drink (serving)	Calories	Sugar
Orange juice (240 ml)	about 108	about 20 g
Regular cola (330 ml can)	about 139	about 33 g
Tonic water (330 ml)	about 112	about 29 g
Regular energy drink (250 ml can)	about 108	about 26 g
Sports drink (500 ml bottle)	about 130	about 26 g

Milky drinks add up fast. A tablespoon of milk has about 6 to 9 calories, so a splash in tea counts the same way as a splash in coffee. Unsweetened almond milk is about 40 calories a cup and oat milk about 108. A whey shake made with one scoop brings about 120 calories. Stirring 12 g of chia seeds (about a tablespoon) into water adds about 58.

Alcohol breaks a fast on calories alone. A 355 ml (12 fl oz) can of regular beer has about 150 calories and a 150 ml glass of red wine about 125. A 25 ml measure of 40% spirits has about 55. In a small study of 8 men, a drink containing 24 g of alcohol cut the body’s fat burning by 73% for some hours. Keep any alcohol inside your eating window.

How much water should you drink while fasting?

The European Food Safety Authority puts adequate total water at 2.0 litres daily for women and 2.5 litres daily for men. That counts water from drinks and food together. Food usually supplies about 20% of it, and on a fasting day you miss part of that share. Drink a little more than usual. Thirst and the colour of your urine are the guide, and pale yellow is the aim.

More is not always better. Drinking too much water can upset the body’s sodium balance. Low blood sodium (hyponatraemia) can make brain cells swell and is a medical emergency. If you have been told to limit fluids because of a heart or kidney condition, keep to your doctor’s advice. A little salt in water is an option on longer fasts, and the electrolytes guide sets out how much salt is sensible on a fast.

Fasting is not right for everyone. Ask a doctor before fasting if you are pregnant or breastfeeding, or under 18. Type 1 diabetes, and diabetes treated with insulin or sulfonylureas, also need a doctor’s advice first. The same goes for any fast that runs past 24 hours. Whatever you drink, we advise against fasting when you are underweight, or after an eating disorder.

For any drink not listed here, search the drink-by-drink fasting database and check its verdict for your goal.