Does one glass of wine break a fast?

Yes. A 5 oz glass has about 120 calories, and your body slows fat burning while it processes the alcohol.

Do spirits like vodka break a fast?

Yes. A 1.5 oz shot of 80-proof vodka has about 97 calories, even though it has no carbohydrates.

Can I drink alcohol during my eating window?

You can, with food and in moderation. Drinking on an empty stomach right after a long fast raises blood alcohol faster.

Does alcohol break ketosis?

Pure spirits may leave ketosis partly in place while the liver burns the alcohol first. Beer, cocktails and sweet wines add enough carbohydrate to end it.

Does Alcohol Break a Fast? Yes

Reviewed by the FastTrack team · Updated June 2026

Short answer: Yes

Yes, alcohol breaks a fast. Alcohol has 7 calories per gram, so a glass of wine has about 120 calories and a light beer about 100. Your liver also slows fat burning while it clears the alcohol.

Calories	~100-150 kcal per drink
Breaks a weight-loss fast?	Yes
Breaks ketosis?	Partial
Breaks autophagy?	Yes
Insulin impact	Low for spirits, higher for beer and mixers

Why a drink ends the fast

The body treats alcohol as a priority fuel: the liver converts it to acetate and burns that first, which pushes fat burning down for several hours. Beer, cider, cocktails and sweet wines add carbohydrates on top. Even a single drink therefore ends a fast for weight loss and halts the processes linked to longer fasting.

Drinking on an empty stomach

After many hours without food, alcohol is absorbed faster and reaches a higher blood level, so one drink can feel like two. It can also lower blood sugar, especially in people taking insulin or sulfonylureas. If you drink, do it inside your eating window, with or after a meal, and alternate with water.

How much is safe

No amount keeps you fasted. Plan any drinks for the eating window and finish a few hours before bed, since alcohol also disturbs sleep.

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Frequently asked questions

Does one glass of wine break a fast?: Yes. A 5 oz glass has about 120 calories, and your body slows fat burning while it processes the alcohol.
Do spirits like vodka break a fast?: Yes. A 1.5 oz shot of 80-proof vodka has about 97 calories, even though it has no carbohydrates.
Can I drink alcohol during my eating window?: You can, with food and in moderation. Drinking on an empty stomach right after a long fast raises blood alcohol faster.
Does alcohol break ketosis?: Pure spirits may leave ketosis partly in place while the liver burns the alcohol first. Beer, cocktails and sweet wines add enough carbohydrate to end it.