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Can you have lemon juice while fasting?

Fasting has become an increasingly popular way to lose weight, improve health, and simplify meal planning. Many different types of fasting exist, ranging from intermittent fasting to extended multi-day fasts. No matter the fasting method, an important question for many fasters is whether or not they can have lemon juice during their fast.

In this comprehensive guide, we’ll explore whether or not lemon juice is allowed on various types of fasts. We’ll also look at the potential benefits and downsides of drinking lemon juice while fasting. Read on to learn everything you need to know about pairing lemons and fasting.

An Overview of Fasting

Before diving into whether or not lemon juice is fasting-friendly, let’s first cover some fasting basics. Here’s a quick overview of some of the most popular fasting approaches:

  • Intermittent fasting: Cycles between periods of eating and fasting, often on a daily or weekly schedule. Examples include the 16:8 diet and the 5:2 diet.
  • Water fasting: Consumes only water for a period of 24 hours up to several days or weeks.
  • Juice fasting: Restricts all foods and consumes only fruit and vegetable juices for a set period of time.
  • Bone broth fasting: Follows a structured fasting protocol but incorporates bone broth during the fast.
  • Liquid fasting: Allows juices, smoothies, and clear soups in addition to water.

Many other variations and combinations of fasting diets exist as well. But in general, most fasting protocols call for severe restriction or complete elimination of solid foods for a period of time.

Is Lemon Juice Allowed During Fasting?

Whether or not lemon juice is allowed depends largely on the specific type of fast:

Fasting Method Is Lemon Juice Allowed?
Water fast No
Juice fast Yes
Intermittent fasting Yes, during eating window
Bone broth fast Yes
Liquid fast Yes

As you can see, lemon juice is not allowed on a pure water fast since you can consume nothing but water. Lemon juice is fair game for juice fasts, bone broth fasts, liquid fasts, and the eating window of intermittent fasting.

Benefits of Lemon Juice While Fasting

Drinking lemon juice while fasting can provide some useful health benefits:

Vitamin C

Lemons are packed with vitamin C, providing about 31mg per 100g of juice. This vitamin serves as an antioxidant and supports immune function.

Alkalizing Effect

Although lemon juice is acidic, when metabolized it produces an alkalizing effect on the body. This can help neutralize acidic waste products.

Weight Loss

Some research indicates that polyphenols in lemon juice may support weight loss and fat burning. So lemon juice may provide a metabolism boost.

Kidney Stone Prevention

Citric acid from lemon juice may help prevent calcium kidney stones by binding with calcium in the kidneys and flushing it out.

Reduced Heartburn

Although counterintuitive, some people report that lemon water reduces heartburn by stimulating digestion. More research is needed on this benefit though.

So in moderation, lemon juice appears to provide some advantages for those fasting with the goal of improving health.

Downsides of Lemon Juice While Fasting

However, there are some potential downsides to consider as well:

Blood Sugar Spikes

Although lemon juice is very low in sugar and calories, it can still stimulate insulin production like other foods. This could inhibit ketosis and fat burning.

Dental Erosion

Frequent exposure to acidic drinks like lemon water can erode tooth enamel over time.


While lemon juice may relieve heartburn for some people, it can make it worse for others due to its acidity.


Since lemon juice has diuretic effects, it could potentially lead to dehydration or loss of electrolytes during a fast.

So it’s important not to overdo it on the lemon juice when fasting. A splash here and there is likely fine, but large amounts could cause some problems.

How Much Lemon Juice Can You Drink When Fasting?

There are no universal guidelines for how much lemon juice is safe or recommended to drink while fasting. Factors like the length of your fast, your overall health, and your body’s response to lemon juice can all impact how much you can tolerate.

That said, here are some general suggestions if you choose to incorporate lemon juice into your fast:

  • Limit lemon juice to 1-2 cups (8-16 oz) per day on shorter fasts of 24-48 hours
  • Restrict lemon juice to no more than 2-4 oz a few times per day on longer fasts of 3+ days
  • Drink lemon juice diluted in water instead of straight
  • Stop drinking lemon juice if you experience dehydration symptoms, diarrhea, heartburn, or other adverse effects
  • Rinse your mouth with plain water after drinking lemon juice
  • Avoid excessive consumption within 1-2 hours of taking supplements or medications

Paying attention to your body’s signals and adjusting your lemon juice intake accordingly is wise. And of course, it’s always best to consult your healthcare provider about the safety of lemon juice or any other aspect of your fasting regimen.

The Bottom Line

So can you have lemon juice while fasting? In most cases, yes – pure water fasts are the main exception. Lemon juice may provide some benefits when fasting, but should be kept to moderate quantities to avoid side effects.

The safest way to add lemon flavor during a fast is by infusing water with fresh lemon slices rather than drinking straight juice. This prevents potential downsides related to the acidity and sugar content of the juice.

As with any fasting program, it’s wise to seek medical advice before beginning, especially if you have any underlying health conditions or take medications. With appropriate precautions and moderation, lemon water can be a refreshing enhancement to a fast for many people.