If you’re up to date on the latest wellness trends, you know that apple cider vinegar (ACV) is *so* much more than a salad dressing. From a face glow-up to a cold remedy, ACV has tons of uses.

It’s typically touted for its health benefits. But is it safe to drink ACV while you’re fasting? And will ACV break a fast? Here’s what you need to know before you sip.

Does apple cider vinegar break a fast?

A tablespoon of undiluted ACV only contains about 3 calories. And it has even less when it’s diluted with water. This means that unless you have a *ton* of it (and please, don’t do that!), ACV won’t break your fast.

Another exception: If you’re dry fasting (which means absolutely no liquid) you can’t drink ACV while fasting. Keep in mind that a dry fast can lead to dehydration. So, be careful.

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What’s the link between ACV and fasting? A research review suggested that consuming ACV may help you feel full, and it might also stabilize your blood sugar levels. Those are both helpful jobs when you’re fasting.

Just keep in mind that this research didn’t include folks that were fasting. It’s possible that ACV won’t have the same effects for people following an intermittent fasting (IF) diet.

There are loads of different types of IF diets, but they all follow the same principle: blocking specific times for when you should be eating, and alternating between eating and periods without eating or undereating.

Let’s get into the deets about ACV and how it interacts with different types of fasting diets.

Nutritional value of apple cider vinegar

When diluted in water to 5 percent acidity, ACV is calorie-free. It also has zero carbs, proteins, and fats.

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16:8 fast

One of the most common IF diets is the 16:8 diet. You’ll fast for 16 hours every day, and eat only during one 8-hour window. There aren’t many strict rules in this type of fast. It’s generally OK to fit two or more meals during the nonfasting period of the 16:8 diet.

Does apple cider vinegar break a 16:8 fast? No. As a calorie-free drink, ACV doesn’t break the 16:8 fast.

5:2 fast

Another popular choice among the IF aficionados is the 5:2 diet. You’ll eat 500 to 600 calories during 2 days, but the rest of the week your diet won’t be restricted. One 2010 study suggested that the 5:2 fast diet may help with weight loss in the same way that calorie restriction does.

Does apple cider vinegar break a 5:2 fast? No. On a fasting day, you just can’t exceed the daily intake (around 600 calories). ACV’s essentially zero calorie count won’t be a concern.

Eat-stop-eat fast

The eat-stop-eat method was created by Brad Pilon. The goal of this diet is to fast for 24-hours straight once or twice per week. This approach might be too extreme if you’re just getting into fasting, so make sure you talk with your doctor before trying it out.

FYI: You’re allowed — and even encouraged — to drink water and other calorie-free sips on this fast. Hydration is important, folks.

Does apple cider vinegar break an eat-stop-eat fast? No. As a calorie-free drink ACV doesn’t break the eat-stop-eat fast.

Alternate-day fast

If you follow the alternate-day fast, you’ll fast *wait for it* every other day. You’re free to eat whatever you want on the days you’re not fasting. The concept of the alternate-day fast is kinda loose, so there are more restrictive versions of this fast. One of those is “modified” fasting, which allows you to eat 500 to 600 calories on fasting days.

Does apple cider vinegar break an alternate-day fast? No. ACV won’t break the alternate-day fast or a modified version of it.

Warrior fast

The warrior fast is all about eating small portions of fruits and veggies during the day, and then one huge meal in the evening. But “small” and “large” aren’t set in stone. You’re encouraged to eat whole foods and avoid processed ones.

Similar to other restrictive fast diets, the warrior fast comes with some potential negative side effects like fatigue, insomnia and hormonal imbalance.

Does apple cider vinegar break a warrior fast? No. Small amounts of condiments (like ACV) are OK to have during the restricted periods of the warrior fast.

It’s generally safe to drink ACV while on a fast as long as you take some precautions. Here are some of the side effects of ACV and how to minimize them.

Nausea. ACV is super acidic, so it can upset your stomach and digestive system. One small 2013 study showed that it can make you feel nauseous (and the taste might not help). You should always (and we mean always) dilute ACV in plenty of water before drinking it.

Erosion of tooth enamel. We’ll say it again: ACV is acidic AF. This can mean trouble to your teeth. Acid erodes tooth enamel, so it’s super important to dilute ACV before drinking it, and rinse your mouth after taking it.

Medication interactions. ACV may also interact with some meds. Make you sure you talk with your doctor about whether you could be at risk of experiencing a nasty interaction before taking ACV.

Is intermittent fasting safe?

Hunger is the most common side effect of intermittent fasting (IF). But if you have diabetes, low blood pressure, or other medical conditions, IF may put you at risk of developing more serious health concerns. Make sure you talk to your doc before trying IF.

It’s important to know that extremely low calorie diets for extensive periods of time can have harmful effects on your health.

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Thirsty for more? If ACV isn’t your thing, you don’t have to stick to plain water while fasting. Here are some delish fast-safe sips you can have while following an IF diet.

Apple cider vinegar works with most fasting diets, as it’s virtually calorie-free when it’s diluted. (And you always need to dilute ACV before drinking it.)

Taking ACV while you’re on an IF diet might even come with some sweet perks, like helping you feel full. But IF isn’t safe for everybody. Talk with your doctor before starting a new diet.