What Breaks a Fast Before Blood Work?
Water, and whatever your lab told you. A fasting blood test usually means 8 to 12 hours with water only — no coffee, no gum, no smoking, no exercise — and that is stricter than any of the five fasting goals on this page. Follow the instruction your clinic gave you over anything here, and read the section below for why the answer changes before surgery.
Show all five goals · Print your fast-safe list
128 foods and drinks, at the serving people actually use — a splash, a teaspoon, one packet.
Five answers per food below. Pick one goal above and each row collapses to a single verdict with its reason.
Nothing in the list matches that.
This is a curated list rather than a search of every food in existence, so the rule of thumb has to cover the rest: if it has calories, it breaks a strict fast. If it has protein, it breaks an autophagy fast. If it is under about ten calories with no protein and almost no carbohydrate, it will not stop fat loss. Try the closest thing on the list, or read the long answer.
Five goals, five answers
"Does it break a fast" has no single answer, because the word means five different things to the five people asking it. Every item here is judged five times, and each line says which question it is answering. No item on this page breaks all five, and that is the whole reason a single yes or no is always wrong about something: bulletproof coffee ends a weight-loss fast outright and helps ketosis; sugar-free gum is fine on four goals and clearly breaks the fifth.
- Strict clean fast
- Any measurable calorie counts. The only one of the five with a clean edge.
- Fat loss
- The question is insulin and energy, not the label. Under roughly ten calories with no protein and little carbohydrate changes nothing.
- Ketosis
- Carbohydrate is the one macro that reliably stops ketone production. Fat does not — it feeds it.
- Autophagy
- No human study has established a calorie or protein threshold, so most of this column honestly reads "nobody knows".
- Gut rest
- The fasted-state motility pattern, which feeding interrupts — and so do some things with no calories in them at all.
What each verdict means
Every verdict also carries how well it is known — established, probable, contested, or not studied in humans. A "breaks it" backed by a calorie count and a "breaks it" backed by a mechanism story are not the same claim, and a tool that prints them identically is hiding the more useful half.
Nothing on this page is a verdict somebody typed. Each one falls out of the item's published numbers, or out of a named mechanism the numbers cannot show, through the rules set out below — which is why the figures are printed next to every answer. A figure can be checked against a source, and an opinion cannot. The same five answers ship inside the Fasted app, and a test holds the two to each other so they can never drift apart.
How many calories break a fast?
There is no established number. No peer-reviewed source sets a 50-calorie threshold, and no human study has quantified how much energy it takes to switch fasting physiology off. The 50-calorie rule is folklore, and the pages repeating it are mostly quoting each other.
What the literature does have points the other way, which is the part almost nobody prints. In a study of 1,422 people, therapeutic fasting on 200 to 250 calories a day still showed glucose falling to low-normal and ketones rising — the metabolic switch, documented, at four or five times the calorie figure people are anxious about. A fasting-mimicking diet reaches a large ketone elevation and an IGF-1 drop at roughly 750 to 1,100 calories a day. Meanwhile the strictest convention in the field, used in the TREAT trial, is water, black coffee or tea and no sweeteners at all. Those are not contradictions. They are four different fasts, and each one is answering a different question.
So the useful question is not how many calories. It is which of your goals a particular thing interferes with, and by what mechanism — which is what the 128 entries below answer.
The one calorie figure worth remembering is a labelling rule rather than a fasting rule: under 21 CFR 101.9 a serving under five calories may be printed as zero. "0 calories" can mean up to 4.9, which is why a sweetener sachet bulked with dextrose and one bulked with erythritol carry identical front-of-pack wording and different answers.
What breaks a fast other than eating?
On a strict fast or a weight-loss fast, nothing you do not swallow. On gut rest, several things — and this is the reason gut rest earns a column instead of being folded into the others.
Chewing gum is the clearest case, and it carries the best evidence on this page. A Cochrane review of 81 randomised trials in 9,072 people found that chewing gum after abdominal surgery shortened the time to first flatus by 10.4 hours and to a first bowel movement by 12.7. Chewing measurably drives the gut with nothing swallowed at all. Black coffee does something similar at two calories: gastrin release, more gastric acid, gallbladder contraction, and colon motor activity rising within four minutes, an effect its researchers put as comparable to a 1000-calorie meal.
Toothpaste and mouthwash do not break anything, because you spit them out. Smoking and vaping put no calories in your stomach, which is not the same as being good for you, and there is no reading of this page where nicotine is an aid to fasting. Medication is its own question and it is answered below.
One caveat that belongs with all of this: the fasted-state motility pattern is real and feeding really does interrupt it, but the review that describes it says plainly that its physiological role is "incompletely understood". Gut rest is a mechanism here, never a promised health benefit, and the 4-to-5 hour meal spacing used in clinical practice is convention grounded in that physiology rather than a trial result.
Does medication break a fast? Ibuprofen, and the rest
A tablet does not break a fast. Pills, capsules and tablets carry no meaningful calories — the labelling rules that flag a sugar load inside a dose only trigger at quantities orders of magnitude above anything in a tablet. So the fasting arithmetic is not the question, and this page gives medication no verdict card, because a verdict card would be answering the wrong thing.
The real question is whether the medicine needs food. Labels say "take with food" for several different reasons: sometimes food is the only way a dose absorbs, sometimes it is there so the drug does not upset your stomach, and sometimes the timing is tied to a meal deliberately. If a medicine needs food, the food wins. It breaks the fast, and that is the correct outcome.
Ibuprofen is the one people search for. The practical advice is to take NSAIDs inside your eating window with food; our guide to taking medication while fasting works through the drug classes one by one. It is worth knowing that whether food actually prevents the gastrointestinal injury is not settled — the effect has only been studied in animals, with results that cut both ways, and the injury mechanism is systemic rather than local, so this page will not tell you food protects your stomach lining.
Never skip, delay or split a dose to protect a fast. If the timing is a problem, that is a conversation with your prescriber or your pharmacist, not a decision to make from a website. Nothing here is advice about your prescription, and the one category where getting it wrong is genuinely dangerous — medicines that lower blood sugar, taken without the meal they were prescribed alongside — belongs with a clinician rather than in a table.
What breaks a fast before blood work?
Water, and whatever your lab told you. The standard instruction for a fasting blood test is 8 to 12 hours with water only — no coffee, no gum, no smoking, no exercise. That is stricter than any of the five goals on this page, and where it differs from them, it wins. Follow the instruction your clinic gave you.
The interesting part is that medicine does not give one answer either. Before surgery, the widely used rule allows clear liquids up to two hours beforehand, and black coffee with no milk counts as a clear liquid — milk in it does not. Before a fasting blood draw, the same cup of black coffee is out. Two medical rulebooks, opposite answers about the same cup on the same morning. That is not sloppiness; it is the same insight this whole page is built on, which is that "does this break a fast" cannot be answered until you say which fast you mean.
Worth knowing separately: for a routine lipid panel, fasting is mostly unnecessary by the 2016 European consensus, and many labs no longer ask for it. That is a decision for whoever ordered the test, not one to make yourself — and it does not change the answer for a glucose or an insulin measurement.
Every food and drink, answered
128 items at the serving people actually use, grouped by where the question usually comes up. Each entry gives the three verdicts, the reason, and the published figures behind them.
Coffee & tea
Does black coffee break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled established
Two calories in a mug. Nothing in coffee moves insulin; what breaks fasts is what people put in it.
8 fl oz (240 ml) · 2 kcal · protein 0.3 g · carbohydrate 0 g · fat 0 g
Does espresso break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled established
A single shot is about one calorie. Same answer as black coffee, in less water.
1 shot (30 ml) · 3 kcal · protein 0 g · carbohydrate 0.5 g · fat 0 g
Does decaf coffee break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Not settled established
Effectively zero. Useful late in a fast when caffeine would cost you the night.
8 fl oz (240 ml) · 0 kcal · protein 0.2 g · carbohydrate 0 g · fat 0 g
Does black tea break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Plain brewed tea is two calories. Milk and sugar are the whole question.
8 fl oz (240 ml) · 2 kcal · protein 0 g · carbohydrate 0.7 g · fat 0 g
Does green tea break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Two calories, and the one drink with a plausible case for helping rather than just not hurting.
8 fl oz (240 ml) · 2 kcal · protein 0.5 g · carbohydrate 0 g · fat 0 g
Does herbal tea break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Near zero. Check the box for added fruit sugars in flavoured blends.
8 fl oz (240 ml) · 2 kcal · protein 0 g · carbohydrate 0.4 g · fat 0 g
Does matcha break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
You drink the leaf, so you get its calories. Small, but not zero the way brewed tea is.
1 tsp powder (2 g) · 6 kcal · protein 0.6 g · carbohydrate 0.7 g · fat 0.1 g
Does instant coffee break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled established
A touch more than brewed, because you swallow the solids. Still trivial.
1 tsp (1.8 g) · 4 kcal · protein 0.2 g · carbohydrate 0.7 g · fat 0 g
Does cold brew break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled established
Black cold brew reads the same as hot coffee. Bottled versions often are not black — read the label.
8 fl oz (240 ml) · 3 kcal · protein 0.3 g · carbohydrate 0.5 g · fat 0 g
Does chicory coffee break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled established
Roasted root, so a few more carbohydrates than coffee. Small enough not to matter for most goals.
8 fl oz (240 ml) · 5 kcal · protein 0.1 g · carbohydrate 1.1 g · fat 0 g
In your coffee
Does heavy cream break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Doesn't break it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
The most-searched borderline item on the internet, and it is not borderline: a tablespoon is fifty calories of fat.
1 tbsp (15 g) · 51 kcal · protein 0.4 g · carbohydrate 0.4 g · fat 5.4 g
Does splash of cream break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
A genuine splash is a third of a tablespoon. Seventeen calories of almost pure fat: it will not spike insulin, but it is not nothing either.
1 tsp (5 g) · 17 kcal · protein 0.1 g · carbohydrate 0.1 g · fat 1.8 g
Does half and half break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Twenty calories, part fat and part milk sugar. Past the point where a fat-loss fast can call it nothing.
1 tbsp (15 g) · 20 kcal · protein 0.5 g · carbohydrate 0.7 g · fat 1.7 g
Does whole milk break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
A tablespoon is nine calories, but it carries lactose and protein — the two things a fast is most sensitive to.
1 tbsp (15 g) · 9 kcal · protein 0.5 g · carbohydrate 0.7 g · fat 0.5 g
Does skim milk break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Fewer calories than whole milk and the same sugar and protein. Taking the fat out does not help the fast.
1 tbsp (15 g) · 5 kcal · protein 0.5 g · carbohydrate 0.7 g · fat 0 g
Does unsweetened almond milk break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Two calories a tablespoon, and the closest thing to a free splash of white in your coffee. Only the unsweetened kind.
1 tbsp (15 ml) · 2 kcal · protein 0.1 g · carbohydrate 0.2 g · fat 0.2 g
Does oat milk break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Made by breaking oat starch into sugar, so it behaves more like a sweet drink than a nut milk.
1 tbsp (15 ml) · 7 kcal · protein 0.1 g · carbohydrate 0.8 g · fat 0.4 g
Does soy milk break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Real protein in it, which puts it out of bounds for an autophagy fast even at a tablespoon.
1 tbsp (15 ml) · 5 kcal · protein 0.5 g · carbohydrate 0.3 g · fat 0.3 g
Does coconut milk drink break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
The carton kind, not the tinned kind. Tinned coconut milk is roughly ten times this.
1 tbsp (15 ml) · 4 kcal · protein 0 g · carbohydrate 0.2 g · fat 0.3 g
Does butter break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Doesn't break it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Pure fat, so insulin barely moves — but thirty-four calories is a real feed, and autophagy answers to energy as well as protein.
1 tsp (4.7 g) · 34 kcal · protein 0 g · carbohydrate 0 g · fat 3.8 g
Does MCT oil break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Doesn't break it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Around a hundred and fifteen calories a tablespoon, and brands declare anywhere from a hundred to a hundred and thirty for the same 14g of fat. It raises ketones, which is why people believe it is free. It is not.
1 tbsp (14 g) · 115 kcal · protein 0 g · carbohydrate 0 g · fat 14 g
Does coconut oil break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Doesn't break it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Same story as MCT oil, slightly more calories and slower to reach the liver.
1 tbsp (14 g) · 121 kcal · protein 0 g · carbohydrate 0 g · fat 13.6 g
Does bulletproof coffee break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Doesn't break it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Two hundred calories is a small meal. It keeps you in ketosis; it does not keep you fasted.
1 tbsp butter + 1 tbsp MCT · 217 kcal · protein 0.1 g · carbohydrate 0 g · fat 24 g
Does sugar break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Sixteen calories of pure glucose and fructose. The smallest amount of anything that reliably ends a fast on every definition.
1 tsp (4.2 g) · 16 kcal · protein 0 g · carbohydrate 4.2 g · fat 0 g
Does honey break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Sugar with trace minerals in it. Your pancreas cannot tell the difference.
1 tsp (7 g) · 21 kcal · protein 0 g · carbohydrate 5.8 g · fat 0 g
Does coffee creamer (powdered) break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Mostly corn syrup solids and vegetable fat. Small serving, but the sugar is real.
1 tsp (2 g) · 11 kcal · protein 0 g · carbohydrate 1.1 g · fat 0.7 g
Does cinnamon break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
A dusting is about two calories. As close to free flavour as a fast gets.
1/4 tsp (0.65 g) · 2 kcal · protein 0 g · carbohydrate 0.5 g · fat 0 g
Does vanilla extract break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Three calories, most of it alcohol. Vanilla syrup is a different item entirely.
1/4 tsp (1 g) · 3 kcal · protein 0 g · carbohydrate 0.1 g · fat 0 g
Water & fizzy drinks
Does water break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
Zero on every count. Drink more of it than you think you need.
any amount · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does sparkling water break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
Carbonated water is water. The bubbles blunt hunger for some people and bloat others.
12 fl oz (355 ml) · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does mineral water break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
Zero calories, and the mineral content is a small bonus on a long fast.
12 fl oz (355 ml) · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does flavoured sparkling water break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Genuinely zero if the label says "natural flavour" and nothing else. Anything listing juice or sugar is a soft drink.
12 fl oz (355 ml) · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Fat loss — not settled: Zero calories, but it tastes of something. Whether sweet or fruity taste alone nudges insulin is unsettled, and it varies by person.
Does diet soda break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Not settled contested — studies disagree
The can declares zero and the manufacturer's own filing to USDA says zero, so a strict fast survives it. USDA's older analysis of a generic diet cola found about seven calories a can, which is the honest caveat. Either way the argument is about sweet taste, not energy.
12 fl oz (355 ml) · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Fat loss — not settled: The cephalic-phase insulin question, and this is where it bites hardest. Pooled trial data show no acute glucose or insulin effect from sweeteners; the WHO advises against them for weight control on long-term observational grounds. Both of those are true at once, and anyone giving you a settled answer is picking one.
Gut rest — not settled: Two things at once here, and neither is the sweetener: the carbonation, and whatever blend the brand uses. Measured on its own, a non-nutritive sweetener did not slow antral motility — a canful of cold fizz is a different question, and not one anybody has run.
Does zero-sugar energy drink break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Usually about ten calories rather than the zero on the front, from taurine and the amino acids in the blend. Brand-dependent — read the panel.
12 fl oz (355 ml) · 10 kcal · protein 0 g · carbohydrate 2 g · fat 0 g
Does regular soda break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Thirty-nine grams of sugar. This is the clearest no on the page.
12 fl oz (355 ml) · 150 kcal · protein 0 g · carbohydrate 39 g · fat 0 g
Does tonic water break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
People file it with soda water. It is sugared: twenty-one grams a glass. Slimline tonic is the zero-calorie one.
8 fl oz (240 ml) · 83 kcal · protein 0 g · carbohydrate 21.5 g · fat 0 g
Does sugar-free squash / cordial break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
A few calories per glass, below the level a label has to declare. Same sweet-taste question as diet soda.
1 serving as directed · 3 kcal · protein 0 g · carbohydrate 0.5 g · fat 0 g
Fat loss — not settled: Too small to feed you; the open question is the sweetness, not the calories.
Does kombucha break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Fermenting eats some of the sugar, not all of it. Thirty calories and seven grams of carbohydrate is a drink, not a fast.
8 fl oz (240 ml) · 30 kcal · protein 0 g · carbohydrate 7 g · fat 0 g
Sweeteners
Does stevia (packet) break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
The label says zero because 21 CFR 101.9 lets any serving under 5 calories be printed as zero. What is in the sachet decides the truth: the dextrose-bulked brands are about four real calories, while the ones bulked with erythritol genuinely are close to nothing. Same front of packet, different answer.
1 packet (1 g) · 4 kcal · protein 0 g · carbohydrate 1 g · fat 0 g
Fat loss — not settled: Four calories cannot feed you. Whether the sweetness itself provokes an insulin response is the unsettled part, and stevia is one of the sweeteners where the human data is thinnest.
Does pure stevia (liquid drops) break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
No bulking agent, so no calories at all. The cleanest way to sweeten anything during a fast.
5 drops · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Fat loss — not settled: Zero energy either way. Only the sweet-taste question remains, and it is genuinely open.
Does sucralose (packet) break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
The sucralose itself is calorie-free; the packet is nearly all dextrose. USDA analysed one and got 3.4 calories and 0.9g of carbohydrate — from the same database the rest of this page runs on.
1 packet (1 g) · 3 kcal · protein 0 g · carbohydrate 0.9 g · fat 0 g
Fat loss — not settled: Small human studies have found sucralose affecting the glucose response when it arrives with carbohydrate, and no effect on its own. Mixed, and not settled.
Does aspartame (packet) break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Same shape as the others: the sweetener is negligible, the bulking agent is sugar. About four calories.
1 packet (1 g) · 4 kcal · protein 0 g · carbohydrate 0.9 g · fat 0 g
Fat loss — not settled: Trials looking for an insulin response to aspartame alone have mostly not found one, but the studies are small. Treat it as probably fine rather than proven fine.
Does monk fruit sweetener break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Almost always blended with erythritol, so the gram on the label is sugar alcohol rather than sugar and delivers nothing. Worth checking yours: a few brands bulk with dextrose instead, which does.
1 packet (1 g) · 0 kcal · protein 0 g · carbohydrate 1 g · fat 0 g
Fat loss — not settled: Barely any absorbed energy. The sweet-taste question applies here as it does to every non-nutritive sweetener.
Does erythritol break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
The one sweetener that is zero by regulation rather than by rounding: 21 CFR 101.9 sets erythritol at 0 calories a gram, because it is absorbed and then passed out in urine unused. The four grams of carbohydrate on the label are real and deliver nothing.
1 tsp (4 g) · 0 kcal · protein 0 g · carbohydrate 4 g · fat 0 g
Fat loss — not settled: No absorbed energy at all, so there is nothing here that can feed you. What stays open is whether the sweet taste itself provokes an insulin response — the effect is real for sugars, and genuinely unsettled for sweeteners.
Does xylitol break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
The sugar alcohol that does carry real energy — about 2.4 calories a gram, and a modest glucose response with it.
1 tsp (4 g) · 10 kcal · protein 0 g · carbohydrate 4 g · fat 0 g
Does allulose break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Absorbed but barely metabolised, so around 0.4 calories a gram. The label still counts the four grams as carbohydrate, because carbohydrate is worked out by subtracting everything else — which is why the calorie figure is the one to read.
1 tsp (4 g) · 2 kcal · protein 0 g · carbohydrate 4 g · fat 0 g
Does sugar-free syrup break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Sucralose in water with flavouring. Genuinely zero, unlike the packets, because there is no bulking agent.
1 tbsp (15 ml) · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Fat loss — not settled: No energy in it. Only the sweet-taste argument, which cuts both ways and is not resolved.
Does agave syrup break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Mostly fructose. It moves blood glucose less than table sugar and it is still five grams of sugar.
1 tsp (7 g) · 21 kcal · protein 0 g · carbohydrate 5.3 g · fat 0 g
Does maple syrup break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Sugar from a tree. Same answer as sugar from a cane.
1 tsp (7 g) · 18 kcal · protein 0 g · carbohydrate 4.7 g · fat 0 g
Does brown sugar break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
White sugar with molasses on it. The molasses is the difference and it is not a meaningful one.
1 tsp (4 g) · 15 kcal · protein 0 g · carbohydrate 4 g · fat 0 g
Supplements
Does creatine monohydrate break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: No human data not studied in humans
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
No calories, and 5 g of creatine on its own had no effect on serum insulin when it was measured directly. One of the few supplements that is genuinely free during a fast.
5 g · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Ketosis — no human data: Nobody has tested plain creatine against ketone production in people. It carries no energy, which is the reason to expect nothing — but expecting nothing and measuring nothing are different, and only one of them has happened.
Does BCAA powder break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Free amino acids carry about four calories a gram, so a 5g scoop is twenty — one brand prints exactly that and another prints zero for the same dose. The supplement most often taken during a fast, and the one that most clearly ends a strict one.
5 g · 20 kcal · protein 5 g · carbohydrate 0 g · fat 0 g
Does EAA powder break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Same arithmetic as BCAAs, with more of the amino acids that trigger a protein response.
5 g · 20 kcal · protein 5 g · carbohydrate 0 g · fat 0 g
Does collagen peptides break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Nine grams of protein. Low in leucine compared with whey, which is why people argue for it — but thirty-five calories and nine grams of protein is a feed on any strict reading.
1 scoop (10 g) · 35 kcal · protein 9 g · carbohydrate 0 g · fat 0 g
Does whey protein break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Twenty-five grams of the most insulin-provoking protein there is. This is a meal in powder form.
1 scoop (30 g) · 110 kcal · protein 25 g · carbohydrate 1 g · fat 0.5 g
Does plant protein powder break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Slightly less insulin response than whey, and still a meal.
1 scoop (30 g) · 115 kcal · protein 22 g · carbohydrate 4 g · fat 2 g
Does multivitamin tablet break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
No energy in it. Fat-soluble vitamins absorb better with food, so a fast costs you some of the benefit rather than the fast.
1 tablet · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does gummy vitamins break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Sweets with vitamins in. Four grams of sugar is small, and it is still sugar.
2 gummies · 15 kcal · protein 0 g · carbohydrate 4 g · fat 0 g
Does fish oil capsule break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
A gram of oil is nine calories. Trivial for fat loss, not trivial for a strict fast.
1 capsule (1 g) · 9 kcal · protein 0 g · carbohydrate 0 g · fat 1 g
Does vitamin D softgel break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
The oil carrier is the only calorie in it. Take it with your first meal — it absorbs far better with fat.
1 softgel · 5 kcal · protein 0 g · carbohydrate 0 g · fat 0.5 g
Does magnesium capsule break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Zero. One of the three minerals worth taking on a long fast.
1 capsule · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does pre-workout break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
The sugar-free kind is around ten calories from citrulline, beta-alanine and flavouring. Ones with dextrose or amino acids are much more.
1 scoop, sugar-free · 10 kcal · protein 0 g · carbohydrate 2 g · fat 0 g
Does apple cider vinegar gummies break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Sugar-coated. If you want the vinegar, take the vinegar.
2 gummies · 15 kcal · protein 0 g · carbohydrate 4 g · fat 0 g
Does melatonin tablet break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Zero calories. The gummy version is not.
1 tablet · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does psyllium husk break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Nearly all of it is fibre you do not absorb, but the label counts it and a strict fast counts it too.
1 tsp (5 g) · 10 kcal · protein 0 g · carbohydrate 4 g · fat 0 g
Does greens powder break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Dried vegetables are still food. Forty-odd calories with protein in it.
1 scoop (12 g) · 45 kcal · protein 2 g · carbohydrate 6 g · fat 0 g
Salt & broth
Does salt break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
A mineral, not a food. Nothing to burn, nothing to store, and on a long fast it is the difference between comfortable and miserable.
1/4 tsp (1.5 g) · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does electrolyte powder (unsweetened) break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
Sodium, potassium and magnesium in water. Check the panel: some brands add dextrose and become a sports drink.
1 stick · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does electrolyte tablet break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Most effervescent tablets carry a couple of grams of dextrose to make the fizz work. Small, but not zero.
1 tablet · 10 kcal · protein 0 g · carbohydrate 2 g · fat 0 g
Does baking soda break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
No calories. A pinch in water is an old trick for heartburn on an empty stomach.
1/4 tsp (1.2 g) · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does bone broth break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Around eight grams of protein a cup, though brands run from five to nine and a half. It breaks a fast on every definition — and it is still the right thing to break a long one with.
1 cup (240 ml) · 38 kcal · protein 8 g · carbohydrate 1 g · fat 0.5 g
Does stock cube (bouillon) break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Mostly salt and flavouring rather than food. Ten calories and it tastes like a meal, which is why it survives long fasts.
1 cube in 1 cup · 10 kcal · protein 0.5 g · carbohydrate 1 g · fat 0.2 g
Does miso soup break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Fermented soy has protein and carbohydrate. A light meal, not a salty drink.
1 cup (240 ml) · 40 kcal · protein 3 g · carbohydrate 5 g · fat 1 g
Does pickle juice break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Vinegar and salt with a few calories from the brine. Cheap electrolytes, and it works for cramps.
1 fl oz (30 ml) · 3 kcal · protein 0 g · carbohydrate 0.6 g · fat 0 g
Juice & soft drinks
Does lemon juice break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
A tablespoon is three calories: technically not a clean fast, metabolically nothing at all.
1 tbsp (15 g) · 3 kcal · protein 0 g · carbohydrate 1 g · fat 0 g
Does lime juice break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Same as lemon, give or take a calorie.
1 tbsp (15 g) · 4 kcal · protein 0 g · carbohydrate 1.3 g · fat 0 g
Does orange juice break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Twenty-six grams of sugar with the fibre taken out. Closer to soda than to an orange.
8 fl oz (240 ml) · 112 kcal · protein 1.7 g · carbohydrate 26 g · fat 0.5 g
Does apple juice break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Sugar water with a fruit on the label.
8 fl oz (240 ml) · 114 kcal · protein 0.2 g · carbohydrate 28 g · fat 0.3 g
Does coconut water break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Marketed as an electrolyte drink, and it is one — with nine grams of sugar attached.
8 fl oz (240 ml) · 44 kcal · protein 0.5 g · carbohydrate 10.4 g · fat 0 g
Does sports drink break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Designed to deliver sugar during exercise, and it does exactly that.
12 fl oz (355 ml) · 80 kcal · protein 0 g · carbohydrate 21 g · fat 0 g
Does vegetable juice break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Less sugar than fruit juice and still a drink with calories and protein in it.
8 fl oz (240 ml) · 50 kcal · protein 2 g · carbohydrate 10 g · fat 0 g
Does milk (glass) break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Sugar, protein and fat together — every lever a fast has, pulled at once.
8 fl oz (240 ml) · 149 kcal · protein 8 g · carbohydrate 12 g · fat 8 g
Does iced tea (sweetened) break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Tea is free; the sugar in bottled iced tea is not. Unsweetened versions read like plain tea.
12 fl oz (355 ml) · 100 kcal · protein 0 g · carbohydrate 26 g · fat 0 g
Does smoothie break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
A meal you drink through a straw. Varies enormously; none of the variants are fasting drinks.
12 fl oz (355 ml) · 250 kcal · protein 4 g · carbohydrate 55 g · fat 2 g
Alcohol
Does vodka / gin / whisky break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
No sugar, and ninety-seven calories your liver drops everything to deal with — including burning fat.
1.5 fl oz (44 ml) · 97 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does dry red wine break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
A glass is a hundred and twenty-five calories. Dry wine is the lowest-sugar option and still ends the fast.
5 fl oz (148 ml) · 125 kcal · protein 0.1 g · carbohydrate 4 g · fat 0 g
Does dry white wine break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Within a few calories of red. Sweeter styles are considerably more.
5 fl oz (148 ml) · 121 kcal · protein 0.1 g · carbohydrate 3.8 g · fat 0 g
Does light beer break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
The lowest-calorie beer is still a hundred calories and a shot of carbohydrate.
12 fl oz (355 ml) · 103 kcal · protein 0.9 g · carbohydrate 5.8 g · fat 0 g
Does regular beer break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Thirteen grams of carbohydrate and alcohol on top.
12 fl oz (355 ml) · 153 kcal · protein 1.6 g · carbohydrate 13 g · fat 0 g
Does hard seltzer break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Low sugar, and a hundred calories of alcohol is a hundred calories.
12 fl oz (355 ml) · 100 kcal · protein 0 g · carbohydrate 2 g · fat 0 g
Food
Does celery break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
The classic "surely this one is free" item. Six calories, and chewing food restarts digestion regardless.
1 stalk (40 g) · 6 kcal · protein 0.3 g · carbohydrate 1.2 g · fat 0 g
Does cucumber break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Almost all water. Almost is the operative word.
1/2 cup (60 g) · 8 kcal · protein 0.4 g · carbohydrate 1.9 g · fat 0 g
Does cherry tomato break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Three calories. Nobody eats one.
1 tomato (17 g) · 3 kcal · protein 0.2 g · carbohydrate 0.7 g · fat 0 g
Does olives break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Mostly fat and salt. Five calories each, and they are the hardest item on this list to stop at one of.
1 olive (4 g) · 5 kcal · protein 0 g · carbohydrate 0.1 g · fat 0.4 g
Does pickle break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Four calories and a lot of sodium. Not clean, but close to it.
1 spear (35 g) · 4 kcal · protein 0.2 g · carbohydrate 0.8 g · fat 0 g
Does sugar-free jelly break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Gelatin is protein, so the ten calories come with an amino-acid signal attached.
1/2 cup · 10 kcal · protein 1 g · carbohydrate 0 g · fat 0 g
Does almonds break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Seventy calories from ten nuts. The most under-counted snack there is.
10 nuts (12 g) · 70 kcal · protein 2.6 g · carbohydrate 2.6 g · fat 6 g
Does egg break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Six grams of protein. A fine way to break a fast; not a way to stay in one.
1 large (50 g) · 72 kcal · protein 6.3 g · carbohydrate 0.4 g · fat 4.8 g
Does Greek yoghurt break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Seventeen grams of protein. This is a meal.
1 pot (170 g) · 100 kcal · protein 17 g · carbohydrate 6 g · fat 0.7 g
Does apple break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Fibre slows the sugar down; it does not remove it.
1 medium (182 g) · 95 kcal · protein 0.5 g · carbohydrate 25 g · fat 0.3 g
Does banana break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Twenty-seven grams of carbohydrate. A pre-workout food, not a fasting one.
1 medium (118 g) · 105 kcal · protein 1.3 g · carbohydrate 27 g · fat 0.4 g
Does avocado break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Low sugar, high energy. Keto-friendly and fasting-incompatible are not the same thing.
1/2 fruit (100 g) · 160 kcal · protein 2 g · carbohydrate 8.5 g · fat 15 g
Does cheese break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Doesn't break it probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Protein and fat together. Insulin responds to cheese more than the carbohydrate count suggests.
1 slice (28 g) · 113 kcal · protein 7 g · carbohydrate 0.4 g · fat 9 g
Does beef jerky break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Protein, and usually sugar in the marinade too.
1 oz (28 g) · 116 kcal · protein 9.4 g · carbohydrate 3 g · fat 7 g
Does peanut butter break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
The spoon straight from the jar is ninety-four calories. There is never only one spoon.
1 tbsp (16 g) · 94 kcal · protein 3.5 g · carbohydrate 3.6 g · fat 8 g
Does dark chocolate break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Even at 85% cocoa, a square is sixty calories.
1 square (10 g) · 60 kcal · protein 0.8 g · carbohydrate 4.6 g · fat 4.3 g
Does rice cake break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Seven grams of fast starch. Diet food that behaves like bread.
1 cake (9 g) · 35 kcal · protein 0.7 g · carbohydrate 7.3 g · fat 0.3 g
Does chicken breast break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: Breaks it probable
- Gut rest: Breaks it probable
Thirty-one grams of protein. Nothing ambiguous here.
100 g cooked · 165 kcal · protein 31 g · carbohydrate 0 g · fat 3.6 g
In your mouth
Does toothpaste break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
You spit it out, so nothing is swallowed and nothing is absorbed. Brush your teeth.
pea-sized, spat out · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does mouthwash break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
Same as toothpaste — as long as you spit. Some brands contain sorbitol, which is why swallowing matters.
20 ml, spat out · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Does sugar-free gum break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Not settled contested — studies disagree
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
About five calories from the sugar alcohols in the base. Small, but a stick every hour adds up faster than people expect.
1 piece · 5 kcal · protein 0 g · carbohydrate 2 g · fat 0 g
Fat loss — not settled: Five calories is nothing. The open question is chewing itself: it starts saliva and a small digestive response, and whether that matters over a long fast has not been settled.
Does regular chewing gum break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Nearly three grams of actual sugar per stick. Swap it for the sugar-free kind.
1 stick · 11 kcal · protein 0 g · carbohydrate 2.9 g · fat 0 g
Does sugar-free mint break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Two calories. As near to free as a thing you put in your mouth gets.
1 mint · 2 kcal · protein 0 g · carbohydrate 0.5 g · fat 0 g
Does Tic Tac break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Sugar, but half a gram of it. Labelled sugar-free in some markets on the serving-size rule, not because there is no sugar.
1 mint (0.5 g) · 2 kcal · protein 0 g · carbohydrate 0.5 g · fat 0 g
Does cough drop break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
A boiled sweet with menthol. Fifteen calories of sugar unless it says sugar-free.
1 drop · 15 kcal · protein 0 g · carbohydrate 4 g · fat 0 g
Does nicotine gum break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Breaks it probable
Sweetened base, a handful of calories. Nicotine itself suppresses appetite and does not feed you.
1 piece · 5 kcal · protein 0 g · carbohydrate 1.5 g · fat 0 g
Does cigarette or vape break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: No human data not studied in humans
- Autophagy: No human data not studied in humans
- Gut rest: Not settled contested — studies disagree
No calories reach your stomach. It does not break a fast, which is not the same as being good for you, and there is no version of this page where nicotine is an aid to fasting.
1 · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Gut rest — not settled: Nicotine is not inert in the gut, and the direction of the effect on fasted-state motility has not been settled. Treat it as an open question rather than a free pass.
Ketosis — no human data: Not studied. Nicotine carries no energy, and no trial has measured what it does to ketone production during a fast.
Does lip balm break a fast?
- Strict clean fast: Doesn't break it established
- Fat loss: Doesn't break it established
- Ketosis: Doesn't break it established
- Autophagy: Doesn't break it established
- Gut rest: Doesn't break it established
Nothing is swallowed. Flavoured ones are still nothing.
1 application · 0 kcal · protein 0 g · carbohydrate 0 g · fat 0 g
Seasoning & condiments
Does apple cider vinegar break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled contested — studies disagree
Three calories. An umbrella review of ten meta-analyses puts the pooled weight effect at about a kilogram, with no significant change in BMI or waist circumference — say the number or say nothing. The glycaemic effect is around carbohydrate meals, not on an empty stomach.
1 tbsp (15 ml) · 3 kcal · protein 0 g · carbohydrate 0.1 g · fat 0 g
Gut rest — not settled: Acid on an empty stomach is not nothing, and the studies that exist looked at what vinegar does to a meal rather than to a fasting gut. Diluted is the only sensible way to drink it either way.
Does black pepper break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Two calories. Season your coffee if you must.
1/4 tsp (0.6 g) · 2 kcal · protein 0.1 g · carbohydrate 0.4 g · fat 0 g
Does mustard break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Three calories a teaspoon. Honey mustard is a different item.
1 tsp (5 g) · 3 kcal · protein 0.2 g · carbohydrate 0.3 g · fat 0.2 g
Does hot sauce break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Vinegar-based hot sauce is about one calorie. Sriracha has sugar in it and runs closer to five.
1 tsp (5 g) · 1 kcal · protein 0 g · carbohydrate 0.1 g · fat 0 g
Does soy sauce break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Three calories, mostly protein, and a great deal of sodium — which on a long fast is a point in its favour.
1 tsp (6 g) · 3 kcal · protein 0.5 g · carbohydrate 0.3 g · fat 0 g
Does nutritional yeast break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Three grams of protein a tablespoon. It tastes like seasoning and behaves like food.
1 tbsp (5 g) · 20 kcal · protein 2.5 g · carbohydrate 2 g · fat 0 g
Does ketchup break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Breaks it established
- Ketosis: Breaks it probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Nearly five grams of sugar a tablespoon.
1 tbsp (17 g) · 19 kcal · protein 0.2 g · carbohydrate 4.7 g · fat 0 g
Does salsa break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Not settled probable
- Autophagy: No human data not studied in humans
- Gut rest: Not settled probable
Chopped vegetables in vinegar. Ten calories, and nobody eats it without a chip.
2 tbsp (32 g) · 10 kcal · protein 0.5 g · carbohydrate 2.3 g · fat 0 g
Does lemon zest break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
One calorie of flavour. Better value than lemon juice if you only want the taste.
1 tsp (2 g) · 1 kcal · protein 0 g · carbohydrate 0.3 g · fat 0 g
Does ginger break a fast?
- Strict clean fast: Breaks it established
- Fat loss: Technically, and it is nothing established
- Ketosis: Technically, and it is nothing probable
- Autophagy: No human data not studied in humans
- Gut rest: Doesn't break it probable
Two calories. Ginger in hot water is one of the few genuinely interesting things you can drink on a fast.
1 tsp grated (2 g) · 2 kcal · protein 0 g · carbohydrate 0.4 g · fat 0 g
Every "does it break a fast" guide on this site
The verdict above is the short answer. Where an item has a page of its own — the evidence, the gray zones, and what changes if you are fasting for a different reason — it is here.
- Apple Cider Vinegar and Fasting: Does It Help?
- Can You Take Supplements While Fasting?
- Do Mints Break a Fast?
- Does Bone Broth Break a Fast?
- Does Sparkling Water Break a Fast?
- Electrolytes During Fasting: Do You Need Them?
- Intermittent Fasting and Alcohol: What You Need to Know
- Protein and Intermittent Fasting: How Much Do You Need?
- What Breaks a Fast? The Definitive Answer
- What Can You Drink While Fasting? The Complete List
- Working Out While Fasting: The Complete Guide
Still not sure what counts? What breaks a fast is the long answer, and the extended fast planner covers the same question over 24, 48 and 72 hours, where the stakes are higher.
And when the fast ends, how to break a fast takes the other half of the question — what to eat first, in what order and how much, sized to how long you actually went.
Print the list, or put this checker on your own site
The printable sheet is one page for one goal: allowed down the left, think-about-it in the middle, breaks-it on the right, with the medication and blood-work caveats at the foot. Pick your goal and print it.
Embed the checker
Free to use on any site. Paste this where you want it — the line underneath the frame is the credit, and it needs to stay visible, because a search engine reading your page cannot see inside an iframe.
<iframe src="https://getfasted.app/tools/does-it-break-a-fast/embed" width="100%" height="560" style="border:1px solid #e5e5e5;border-radius:12px;" loading="lazy" title="Does it break a fast? checker"></iframe> <p>Free <a href="https://getfasted.app/tools/does-it-break-a-fast">what breaks a fast checker</a> by Fasted</p>
Preview the widget · it renders every verdict as plain text on the server, so it works with scripts turned off.
How this is calculated
Every verdict starts from published nutrition data, not from opinion. Calories, protein, carbohydrate and fat per serving come from the USDA FoodData Central database, and the serving sizes are the ones people actually use — a splash of milk, a teaspoon of sugar, one packet of sweetener. Nothing here stores a hand-written yes or no: five rules turn those numbers into five answers, and each one says which question it is answering. Strict clean fast: anything with measurable calories breaks it, because the only unambiguous definition of a fast is zero energy. Fat loss: the question is insulin and energy, so items under roughly 10-15 calories with no protein and little carbohydrate are called trivial rather than breaking. Ketosis: carbohydrate your body actually burns is the lever — declared carbohydrate is capped by the calorie figure, because fibre and sugar alcohols sit inside the declared grams and deliver nothing — and fat does not stop ketone production, it feeds it. Gut rest: the fasted-state motility pattern, which responds to arrival rather than arithmetic, so chewing and coffee land here even at no calories. Autophagy: no human study has established a calorie or protein threshold, and there is no way for a person to measure their own, so this column reads "no human data" for almost everything and says why. It keeps two ends only — water, salt and zero-calorie electrolytes really are clean, and food really is food. Any page that gives you a gram figure for when autophagy stops has made it up, and until 31 August 2026 this one did too.
Curated client-side dataset built from USDA FoodData Central published values. Live-API mode is gated on services.usda.api_key being set.
Where this comes from
- 1. FoodData Central — U.S. Department of Agriculture, Agricultural Research Service
- 2. Measuring autophagy in humans: an overview of the current state of the field — Bensalem et al., The Journal of Physiology, 2025 (Europe PMC, PMID 40345145)
- 3. Effect of prolonged fasting on autophagy markers in human skeletal muscle — Dethlefsen et al., Journal of Applied Physiology, 2018 (Europe PMC, PMID 30161009)
- 4. Chewing gum for postoperative recovery of gastrointestinal function — Short et al., Cochrane Database of Systematic Reviews, 2015 (Europe PMC, PMID 25914904)
- 5. Coffee and gastrointestinal function: facts and fiction — Boekema et al., Scandinavian Journal of Gastroenterology, 1999 (Europe PMC, PMID 10499460)
- 6. The migrating motor complex: control mechanisms and its role in health and disease — Deloose et al., Nature Reviews Gastroenterology & Hepatology, 2012 (Europe PMC, PMID 22450306)
- 7. Nutrition labeling of food — 21 CFR 101.9 — Electronic Code of Federal Regulations, U.S. Government Publishing Office
- 8. Effects of Intermittent Fasting on Health, Aging, and Disease — de Cabo & Mattson, New England Journal of Medicine, 2019 (PubMed)
Nothing on this site is medically reviewed — it cites its sources so you can check them. Read our editorial policy. Method last checked 31 August 2026.
The whole fast, in four tools
These four were built to sit together. One plans the window, one answers what may go in while it runs, one handles the meal that ends it, and one covers the fasts too long to be a daily schedule.
- Plan Fasting Schedule Planner When the window is, every day of the week — with a calendar file and a sheet.
- Hold Does It Break a Fast? — you are here. Whether a thing breaks the fast, item by item, for five different goals.
- End How to Break a Fast What to eat first when it finishes, in what order, by how long you fasted.
- Longer Extended Fast Planner A single fast of 24 hours or more, planned hour by hour.