Intermittent fasting has become an increasingly popular way to lose weight, improve health, and simplify eating habits. During the fasting period, only water, black coffee, and zero-calorie beverages are typically allowed. But some people also opt to drink apple cider vinegar, believing it won’t disrupt the fasted state.
This article reviews whether apple cider vinegar breaks a fast and how it affects health during intermittent fasting.
What Is Intermittent Fasting?
Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. It doesn’t specify which foods to eat but rather when to eat them.
There are several different types of intermittent fasting including:
- The 16/8 method involves fasting for 16 hours per day and restricting meals to an 8-hour window.
- The 5:2 diet involves eating normally 5 days per week and restricting calories to 500–600 on 2 days.
- Alternate day fasting involves fasting every other day.
- The warrior diet involves eating small amounts of raw fruits and vegetables during the day and eating one large meal at night.
The most common method is the 16/8 protocol, which is often paired with the keto diet for synergistic weight loss effects.
Apple Cider Vinegar for Fasting
Apple cider vinegar (ACV) is a type of vinegar made from fermented apple cider. It’s a popular natural remedy for a variety of health issues.
Some people also like to drink apple cider vinegar during their fasting periods, citing benefits like:
- Suppressing appetite
- Aiding digestion
- Boosting energy
- Supporting blood sugar control
However, others argue that apple cider vinegar could disrupt the fasted state and negatively impact health.
So does apple cider vinegar actually break a fast?
Does Apple Cider Vinegar Have Calories?
One of the main concerns with apple cider vinegar is that it could contain calories that disrupt the fasting period.
In fact, apple cider vinegar packs just 3 calories per tablespoon (15 ml).
Most people consume 1–2 tablespoons (15–30 ml) mixed with water as a drink before meals.
At this amount, apple cider vinegar provides 6–12 calories, which is very low. By comparison, a small apple packs around 95 calories.
However, when you look at the ingredients list of store-bought apple cider vinegar, sugar is almost always added. The amount can range from 1/2 teaspoon (2 grams) up to 1 tablespoon (13 grams) per serving.
This equates to 8–52 calories, which could technically break your fast depending on how much you consume.
To keep your fast clean, look for an organic, unfiltered apple cider vinegar that doesn’t contain any added sugars.
Does It Stimulate Insulin Secretion?
In addition to potential calorie intake, some claim that apple cider vinegar could impact fasting by stimulating insulin secretion.
Insulin is a hormone that regulates blood sugar levels. It’s secreted in response to consuming carbohydrates.
Spiking insulin can minimize the benefits of fasting by taking your body out of the fasted state. For this reason, anything that stimulates insulin secretion is considered inappropriate for use during fasting periods.
However, current research shows vinegar has a negligible effect on insulin levels.
In one study, vinegar consumption actually decreased post-meal insulin by 20% compared to a placebo. What’s more, blood sugar dropped by over 30% (1).
Another study in 11 healthy adults showed that taking apple cider vinegar with a high carb meal significantly lowered blood sugar and insulin compared to a placebo (2).
Based on current research, apple cider vinegar seems to improve insulin sensitivity rather than spike insulin levels after a meal.
Other Effects on Health
In addition to its minor effects on calories and insulin, apple cider vinegar impacts health in several other ways during fasting.
One of the challenges of fasting is that it increases hunger levels. This can make it harder to stick to the fast.
Interestingly, studies show that vinegar could help suppress appetite.
In one study, 14 people took vinegar with bread and reported feeling twice as full compared to the placebo group (3).
Apple cider vinegar may also promote fullness, which could prevent overeating and enhance the effects of your fast.
Apple cider vinegar is well known as a digestive aid. It’s often recommended as a natural remedy for heartburn, acid reflux, and indigestion.
This is because it can help stimulate stomach acid production, which may improve the digestion of food (4).
Boosting digestion may also promote feelings of fullness after a meal, which could support your fast.
Benefits Blood Sugar Control
Enhancing blood sugar control is one of the key benefits of fasting. In fact, research shows intermittent fasting could reduce blood sugar by 3–6% in those with prediabetes (5).
Apple cider vinegar may also help control high blood sugar levels, especially when paired with a high carb meal.
One study showed that vinegar reduced blood sugar by 34% after eating a bagel and juice. Fasting blood sugar was also reduced by 4% (6).
Another study in people with diabetes found that taking apple cider vinegar before bed lowered fasting blood sugar by up to 6% the next morning (7).
Regulating blood sugar is important during fasting periods to keep levels stabilized and prevent spikes.
May Delay Gastric Emptying
Some research shows that vinegar may alter levels of stomach enzymes needed for digestion, which could delay gastric emptying.
This could impact how food moves through your digestive tract after eating (8).
Increasing gastric emptying time slows the speed at which food exits your stomach. This leads to increased feelings of fullness and a longer time to digest meals (9).
Delaying emptying of the stomach may also help stabilize blood sugar levels after eating to enhance the beneficial effects of fasting (10).
Supports Heart Health
Emerging research shows that vinegar could benefit heart health by decreasing several risk factors for heart disease.
Each of these factors is directly linked to heart disease, especially among people with obesity and diabetes (13).
Pairing apple cider vinegar with an intermittent fasting regimen may be an effective strategy to boost heart health.
How to Drink Apple Cider Vinegar
It’s best to stick to 1–2 tablespoons (15–30 ml) of apple cider vinegar per day to maximize potential benefits while minimizing side effects.
Mix 1–2 tablespoons (15–30 ml) of apple cider vinegar with a glass of water and drink it before meals.
You can decrease the taste by diluting further with more water. It’s best to use organic, unfiltered apple cider vinegar that contains the “mother.”
Start with 1 teaspoon (5 ml) and gradually work up to 1–2 tablespoons (15–30 ml) per day to assess your tolerance.
Don’t drink it undiluted, as the acidity can harm your teeth and throat. You can also take apple cider vinegar tablets if you can’t tolerate the taste.
Safety and Side Effects
There are a few safety concerns with apple cider vinegar.
Because it’s highly acidic, straight vinegar could damage tooth enamel and the esophagus. Be sure to dilute it in water or juice and rinse your mouth with plain water after drinking it (14).
If you experience side effects like digestive issues, delayed stomach emptying or nausea, try decreasing the dose.
Be aware that apple cider vinegar may interact with certain supplements and drugs like diuretics and insulin. Speak to your healthcare provider before starting to use it.
Some people may need to avoid apple cider vinegar, including those with gastroparesis, kidney disease, low potassium levels, or acid reflux.
Additionally, be sure to purchase vinegar with the “mother” to get the most nutritional and health benefits.
The Bottom Line
Apple cider vinegar won’t likely break your fast or ruin its beneficial effects.
It may actually enhance the health benefits of fasting by suppressing appetite and aiding digestion. Apple cider vinegar also provides a wide range of additional health benefits.
Stick to 1–2 tablespoons (15–30 ml) diluted with water per day to minimize potential side effects and impact on fasting.
As long as you use organic, unfiltered apple cider vinegar, it can be a nutritious and delicious addition to an intermittent fasting regimen.
Frequently Asked Questions
Does apple cider vinegar end autophagy?
No evidence shows that apple cider vinegar disrupts autophagy, the self-cleaning process your body undergoes during fasting periods. Autophagy provides most of the health benefits linked to intermittent fasting.
Can you drink apple cider vinegar while water fasting?
Yes, it’s fine to drink small amounts of apple cider vinegar even during a water fast. Up to 1-2 tablespoons (15-30 mL) per day is unlikely to impact your fast or health.
Will apple cider vinegar stall ketosis?
No, apple cider vinegar is very low in carbs and calories and won’t disrupt ketosis or fat burning during keto and fasting periods.
Can I drink apple cider vinegar before bed?
It’s best to avoid it before bed. Acetic acid in vinegar could delay gastric emptying and impact sleep. Drink apple cider vinegar diluted with water 30-60 minutes before meals earlier in the day.
Does apple cider vinegar break an intermittent fast?
Apple cider vinegar is unlikely to break your fast or affect your health during intermittent fasting. It may actually enhance the benefits of fasting by aiding digestion, fullness, and blood sugar control.
The Bottom Line
Apple cider vinegar can be a healthy addition to an intermittent fasting regimen. It provides minimal calories and carbs and may actually enhance some of the health benefits of fasting. Stick to 1-2 tablespoons (15-30 mL) per day diluted in water and rinse your mouth after drinking it.