Does Apple cider vinegar break a fast?
Apple cider vinegar does not break a fast when used as directed — its calorie and insulin impact is negligible for standard fasting goals.
Calories
~3 kcal per tablespoon (15 ml)
Why — the calorie and insulin logic
A tablespoon of apple cider vinegar (ACV) contains about 3 kcal, primarily from acetic acid. It does not trigger a meaningful insulin response at this dose. Some research suggests acetic acid may improve insulin sensitivity and slow gastric emptying, which could support fasting goals rather than hinder them.
Does it depend on your fasting goal?
Generally considered fast-safe for weight-loss and metabolic fasting when diluted in water. For autophagy fasting, the trace calories are negligible. Avoid ACV drinks with added sugar, honey, or fruit juice — those will break a fast. Always dilute ACV to protect tooth enamel.
Frequently asked questions
- Does apple cider vinegar break a fast?
- Plain diluted ACV (1–2 tablespoons in water) is generally considered fast-safe. Its 3 kcal per tablespoon and acetic acid content do not produce a meaningful insulin response.