What Breaks a Fast? A Clear Guide to Coffee, Tea, Lemon Water and More

October 3, 2026 avinashmittal

If you’re trying intermittent fasting, the rules can feel confusing. Can you have coffee? What about lemon water, diet soda or your morning creatine? Here’s a clear, evidence-based answer to what breaks a fast, item by item.

Quick answer: The simplest rule is that anything with calories breaks a fast. According to Johns Hopkins Medicine, water and zero-calorie drinks such as black coffee and plain tea are fine during your fasting window. Milk, cream, sugar, juice, broth and protein drinks all add calories and break a fast. Items with only a few calories, like a squeeze of lemon or a piece of sugar-free gum, are a gray area.

The Simple Rule: Calories Break a Fast

Intermittent fasting means switching between periods of eating and periods of not eating, for example eating within 8 hours and fasting for 16, as Johns Hopkins neuroscientist Mark Mattson explains. During the fasting period, the goal is to take in no calories. That’s why zero-calorie drinks are allowed and anything with calories technically ends the fast.

In real life, some people allow a tiny number of calories, such as a splash of lemon, and still get on fine. If you want a clear rule you never have to second-guess, stick to zero-calorie drinks.

What Breaks a Fast: Quick Reference Table

Item	Breaks a fast?	Why
Water (still or sparkling, unflavored)	No	No calories
Black coffee	No	Zero-calorie drink allowed during fasting, per Johns Hopkins
Plain tea (black, green or herbal)	No	Zero-calorie drink, as long as nothing is added
Coffee or tea with milk, cream or sugar	Yes	Milk, cream and sugar add calories
A squeeze of lemon in water	Gray area	Adds a few calories; lemonade or sweetened lemon water breaks a fast
Diet soda	No calories, but see below	Calorie-free, but WHO advises against sweeteners for weight control
Sugar-free gum	Gray area	Sugar alcohols in gum contain some calories
Creatine	Depends on the product	Check the label: unflavored products with 0 calories won’t add any
Juice, smoothies, bone broth	Yes	All contain calories
Protein shakes, collagen, BCAA drinks	Yes	Protein and amino acid products contain calories

Does Black Coffee Break a Fast?

No. Black coffee is a zero-calorie drink, and Johns Hopkins lists it among the beverages that are permitted while you’re fasting. Can you drink coffee while intermittent fasting? Yes, as long as it’s black. Adding milk, cream, sugar, flavored syrup or a sweet creamer adds calories, and that does break a fast.

Does Tea Break a Fast?

No. Plain tea, whether black, green or herbal, is a zero-calorie drink and is allowed during fasting. Watch out for sweetened bottled teas, chai lattes and anything with honey, milk or sugar, which all break a fast.

Does Lemon Water Break a Fast?

Technically, a squeeze of lemon adds a few calories from the juice, so under the strict rule it breaks a fast. In practice, the amount is very small, and many people treat a slice or a squeeze of lemon as fine. Lemonade, honey-lemon drinks or a whole glass of lemon juice are a different story: those clearly break a fast.

Does Diet Coke Break a Fast?

Diet sodas are calorie-free, so they don’t add calories during your fasting window. But if you’re fasting to lose weight, keep this in mind: the World Health Organization advised in 2023 against using non-sugar sweeteners to control body weight, because its review found they don’t provide a long-term benefit in reducing body fat. The WHO called the evidence low certainty and said the advice doesn’t apply to people who already have diabetes. Water, black coffee and plain tea are simpler choices.

Can You Chew Gum While Fasting?

Sugar-free gum is a gray area. It’s often sweetened with sugar alcohols, which, as the WHO notes, contain calories. A single piece adds very little, but several pieces add up. Regular gum with sugar breaks a fast. If you’re strict about your fast, skip gum until your eating window.

Does Creatine Break a Fast?

It depends on the product. Many creatine powders are plain and list 0 calories on the label, so they won’t add calories. Flavored or pre-mixed products can contain sugar or other ingredients with calories. Check the nutrition label: if it lists calories, it breaks a fast. You can also simply take creatine during your eating window.

What Breaks a Fast for Sure

Any food, including a small snack
Milk, cream, sugar, honey and flavored syrups
Juice, smoothies, sweetened drinks and alcohol
Bone broth and soups
Protein shakes, collagen, and BCAA or other amino acid drinks

Don’t skip prescribed medicines because you’re fasting. If a medicine needs to be taken with food, or you take medicine for diabetes, talk to your doctor before you start fasting.

Does It Matter for Weight Loss?

If your main goal is losing weight, total calories matter more than the exact fasting rules. In a 12-month trial published in the New England Journal of Medicine, 139 adults with obesity followed a calorie-reduced diet either within an 8-hour eating window or with no time limit. People in the time-restricted group lost 8.0 kg and those in the calorie-only group lost 6.3 kg, a difference that wasn’t statistically significant. The authors concluded that time-restricted eating wasn’t more effective than cutting calories alone.

In other words, intermittent fasting works for weight loss mainly because it helps some people eat less. A few stray calories during your fast won’t make or break your results, but what you eat in your eating window will. Pairing your plan with daily movement helps too: see our guide to how many steps a day to lose weight.

What to Eat to Break a Fast

There’s no single perfect first meal, but a balanced, moderate meal tends to work better than a huge one. Good options include protein (eggs, yogurt, beans, fish or chicken), vegetables or fruit for fiber, and some whole grains. Drink water with it, and try not to treat the end of your fast as a reason to overeat.

Who Shouldn’t Try Intermittent Fasting

Johns Hopkins advises against intermittent fasting for:

Children and teens under 18
People who are pregnant or breastfeeding
People with type 1 diabetes who take insulin, because of the risk of low blood sugar
Anyone with a history of eating disorders

If you have type 2 diabetes or take medicine that affects blood sugar, talk to your doctor first. Our guide to normal A1C levels explains how blood sugar control is measured.

Frequently Asked Questions

Does black coffee break a fast?

No. Black coffee is a zero-calorie drink that’s allowed during fasting. Milk, cream or sugar would break it.

Does tea break a fast?

Plain tea doesn’t. Sweetened or milky tea does.

Does lemon water break a fast?

A small squeeze adds only a few calories and is a gray area. Sweetened lemon drinks break a fast.

Can you drink water while intermittent fasting?

Yes. Water is always allowed, and staying hydrated is a good idea while fasting.

Does creatine break a fast?

Plain creatine labeled 0 calories doesn’t add calories. Flavored mixes may, so check the label.

The Bottom Line

What breaks a fast? Anything with calories. Water, black coffee and plain tea are safe choices; milk, sugar, juice, broth and protein drinks end your fast; and small extras like lemon or sugar-free gum are a gray area. For weight loss, what and how much you eat in your eating window matters most.