What you can drink while intermittent fasting (full list)
Water, coffee, tea, broth… and the traps you do not see coming. The definitive list of what to drink without breaking your fast.
Part of the complete guide What breaks a fast (and what doesn't)
What the science saysWhat can you drink while fasting? A clear list
During intermittent fasting you can have water (still or sparkling), black coffee, and tea or herbal teas with no sugar or milk: they bring almost no calories and do not interrupt the fast. Juice, sugary soda, milk, shakes and alcohol break it. Zero-calorie sweeteners are a gray zone: in some people they alter the insulin response.
- Sucralose taken before a glucose load raised the insulin area by 20% and the glucose peak in 17 people with obesity (Pepino 2013). [1]
- Coffee 3-4.5 h before a meal barely affects intake; caffeine 0.5-4 h before can reduce it acutely (Schubert 2017). [2]
- Fasts of 4-21 days on broth and juice (200-250 kcal/day) were well tolerated in 1,422 people; 93.2% felt no hunger (Wilhelmi de Toledo 2019). [3]
The golden rule
During your fast, the rule is simple: if it has calories, it breaks your fast. Anything with zero (or nearly zero) calories that does not spike insulin is fair game.
Drinks you can have ✅
- Water (still or sparkling). The foundation.
- Water with lemon, or cucumber and mint slices (no sugar).
- Black coffee, no sugar, no milk.
- Tea and herbal teas with no sugar (green, rooibos, mint, chamomile…).
- Very light bone or vegetable broth — useful on long fasts for the electrolytes (heads up: it does add some calories, so it is not a strict fast).
Drinks that break your fast ❌
- Juice (even fresh-squeezed: it is pure sugar).
- Regular soda.
- Coffee with milk or sugar, cappuccino, latte.
- Shakes, smoothies, plant milks.
- Alcohol.
The gray zone: diet soda and sweeteners
Zero-calorie sodas have no calories, so technically they do not break your fast. But the sweet taste can stir up appetite and insulin in sensitive people, and they bring nothing good to the table. If you use them, keep it occasional. Sparkling water with lemon is a better call.
Electrolytes: the long-fast trick
On fasts over 18-24 h, part of the discomfort (headache, dizziness) comes from losing sodium, potassium and magnesium. A pinch of salt in your water, or an electrolyte supplement with no sugar, helps a lot and does not break your fast.
How Ayúname helps
Ayúname reminds you to hydrate and tells you which phase you are in, so you know when broth or electrolytes make sense. Fewer doubts, more consistency.
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Frequently asked questions
Does sparkling water break a fast?
Can I have broth while fasting?
Does diet soda break a fast?
Scientific sources (4)
- Sucralose Affects Glycemic and Hormonal Responses to an Oral Glucose Load. Diabetes Care, 2013.
- Caffeine, coffee, and appetite control: a review. International Journal of Food Sciences and Nutrition, 2017.
- Safety, health improvement and well-being during a 4 to 21-day fasting period in an observational study including 1422 subjects. PLOS ONE, 2019.
- De novo lipogenesis, lipid kinetics, and whole-body lipid balances in humans after acute alcohol consumption. The American Journal of Clinical Nutrition, 1999.