Apple cider vinegar does not break a fast in typical amounts. One tablespoon has about three calories and almost no sugar, so it will not raise insulin or end your fast, and it may slightly blunt blood sugar.
| Calories | ~3 kcal per tbsp |
|---|---|
| Breaks a weight-loss fast? | No |
| Breaks ketosis? | No |
| Breaks autophagy? | No |
| Insulin impact | Minimal, may lower |
A tablespoon of apple cider vinegar contains roughly three calories and a negligible amount of carbohydrate. It does not provide the energy or insulin response needed to break a fast. Some research suggests vinegar can modestly improve insulin sensitivity and blunt post-meal blood sugar, which is why some people take it during a fast.
Always dilute ACV in water, as straight vinegar can irritate the throat and tooth enamel. ACV gummies are a different story: many contain added sugar, so the sweetened versions can break a fast.
One to two tablespoons diluted in a large glass of water is the usual amount and stays well within a fast.
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