21 Days Juice Fasting | Ultimate Guide

This content has been Fact-Checked by a Certified Nutritionist in our Publishing Team. Learn more here. Always consult a medical professional before commencing any diet.

21 days juice fasting is a very popular option when it comes to detoxing.

I personally have not tried it however I do love fresh juice and a good detox.

I do have to say though, drinking juice for 21 days will require some determination!

The results?

Apparently, it can remove body toxins, eliminate a health condition that is bothering you, and simply help you feel physically and mentally healthy.


Find out how to get ready for it and more:

What is the 21 Days Juice Fasting?

Juice fasting or juice cleanse, involves consuming fresh vegetable and fruit juices, as well as water and herbal teas. You can easily make the juices at home or buy them from a store (only make sure it is 100% natural).

Juice fasting has numerous health benefits such as improved skin, focus and mental clarity, reduced inflammation, higher energy level and etc.

The length of the fast is usually determined by your fasting experience and your commitment. So, if you are new to juice fasting, it would be wise to start with 1-5 days and then gradually aim for longer periods.

Check out our article, Juice Fasting – The Complete Guide For Weight Loss, to familiarize yourself with general concepts of this practice and learn how to apply 1-7 days of juice fasting.

21 days juice fasting is considered a long-term fast. Thus, only experienced fasters should attempt to do it.

Long juice fasts are generally more preferable, as they give your body an opportunity to perform continuous healing and cleanse.

21 Days Juice Fasting Phases

fruits and vegetables

A lot of preparation needs to be done before you start your fast. You should already have a schedule of juices you are going to drink and have your ingredients ready.

Phase 1: Day 1-2 (Getting started)

As you may have guessed, the first few days of the fast are usually the hardest. So, be prepared to experience a little discomfort, as your body tries to adapt to your new diet.

In this stage your body switches to “battery save mode” and that’s why most of the beginner fasters lack energy. Not to mention the feeling of hunger that kicks in and makes you feel irritated and moody.

The reason for having low energy in this phase is that when fasting, your BMR becomes more efficient and slows down. As your body is in “battery saving mode”, it uses less energy, lowers blood pressure and the heart rate.

But if you keep on fasting and survive these few days, your energy levels will rise up soon.

Phase 2: Day 3-7 (Weight loss)

Now, you will notice changes in your appearance since, in this stage, your body starts burning stored fat for energy. This process is called ketosis.

Burning fat means losing weight. Hence, your weight will change as fat is gradually being burned, which also has a detoxifying effect.

Phase 3: Day 8-15 (Healing mode)

At this stage, after 1-week fasting becomes much easier. You are in a good mood and your body is already used to fasting.

Your mind is clear and your immune system becomes stronger. Moreover, the body finally takes a rest and start healing itself, as it gets rid of most of the toxins and free radicals.

Also, the overall health will improve as you get free from stress and harmful substances. As a result, you are less prone to health problems and your body is more likely to achieve healthy aging.

Phase 4: day 16-21 (Balance)

If you choose to continue until Phase 4, you will not feel any additional changes. This is a balanced stage, where your body will continue healing and cleansing itself.

Extended fasting is not advised to perform without the doctor’s supervision. If not done right, fasting may cause severe damage to your health. So, take care of yourself and consult your doctor first.

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What should you drink?

girl fruits

During your fast, you are going to consume fresh juices made of vegetables, juices, and herbs. Usually, it is preferable to use fewer fruits and base 50% of your drinks on green vegetables due to lower sugar amount.

Ideally, you should consume 4-6 cups of juice (500-600ml each) per day. Plus, you are allowed to have herbal teas 2 times a day between your juices. And don’t forget to stay hydrated (at drink water at least 8 cups/day).

Here is how you can distribute your juice ingredients:

Option 1:
Each of 6 juices are made of 20% fruits and 80% vegetables.
Option 2:
For breakfast, you can drink all fruit juice and make the rest of the juices 100% vegetable.
Option 3:
Equally distribute the ingredients for the first 2 juices (50% fruit, 50% vegetables) and make the remaining 4 juices entirely vegetable-based.

Remember, the 20/80 rule works the best i.e. the juice contains 20% fruits and 80% vegetables.

Also, when choosing which fruit or vegetable to add in your juice, try to avoid the ones that are high in carbs. You can find a complete list of low-carb ingredients here.

21 Days Juice Fasting Pros and Cons

Juicing has become very popular in recent years. The advocates claim that juice fasting for an extended period can have a number of positive effects on the body, such as helping to get rid of certain health issues (insomnia, anxiety, etc.).


woman scale

1. Vitamins and minerals

You might not be able to get the complete set of vitamins in your regular diet, but when you start consuming only juices, there is no need to worry about that. Fruits and vegetables contain a high amount of minerals and vitamins that boost the immune system and overall health. The nutrients are easily absorbed when consumed in a liquid form.

According to research from Linköping University, Sweden, consuming spinach in the form of juice or smoothie, maximizes your chance in getting the antioxidant lutein which is found in the juice in a higher amount than the raw form.

2. Weight loss

When your body is in ketosis it will burn stored fat for energy which results in weight loss. Also, when you abstain from eating solid foods, your body quickly loses the excess water weight which will reflect on your scale. During the fast, you are consuming healthier foods and fewer calories which will also make you lose weight.

3. Improved health

Juice fasting helps the body to flush out the toxins. The special compounds in fruits and vegetables have an anti-inflammatory effect on the body. Also, your digestive system gets a lot improved and you feel energetic and light.

Researches found that vegetable/fruit juice diet showed an improvement in gut microbiome

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Like any restrictive diet, juice fasting has its drawbacks too. Relying only on fruits and vegetables can be risky for your health. Therefore, it is important to understand what are the cons of this particular diet to have realistic expectations and take precautions where needed.

1. Risk of kidney disorder

Some ingredients may contain a high amount of oxalate, which may contribute to kidney stones. That’s why it is good to be aware of the foods that have high levels of oxalate to balance your diet and avoid such problems.

This is especially advised for people who previously had issues with kidney stones. Also, it is best to consult a doctor for such cases.

List of foods high in oxalate

  • Sweet potatoes
  • Beets
  • Spinach
  • Kale
  • Beet greens
  • Star fruit
  • Chard
  • Turnip greens
  • Rhubarb
  • Endive

2. Risk of losing muscle mass

Protein is necessary for maintaining your muscles. During your fast, you will consume less protein and this increases the chance of losing muscle mass. It can create serious health problems, as your metabolism slows down and you lose strength.

For fasters, who do juice fasting frequently, it is advised to do some strength training after the fasting to rebuild the muscles.

3. Weight loss may be temporary

Juice fasting alone is not enough for lasting weight loss results. As soon as you break the fast and go back to your normal diet, you will regain the weight.

Besides, continuing a prolonged juice fasting is not advised due to health concerns, that’s why the results are short-term.

4. Juice fasting can get expensive

There is a certain difference between juicing and blending.

– Juicing involves making vegetable and fruit juice without the pulp or fibrous components, i.e. squeezing the juices from the ingredients.

– When you blend you mix all the parts of fruits and vegetables together, including the pulp.

This means juicing requires more fruits and vegetables per portion. For a really healthy juice, you will need to buy fresh and organic ingredients, which are not that cheap. Also, you might need to buy a decent juicer if you don’t have one.

Buying freshly made juices can also cost a lot. Usually, a bottle of raw cold-pressed juice from well-known brands costs about $8 dollars. If you drink 1 bottle per day for 21 days, it adds up to around $168 dollars per person.

5. A decrease in blood sugar and pressure: so it is contraindicated to the diabetic patients to follow this diet.

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21 Days Juice Fasting Results

It is very hard to tell exactly what results you can expect from 21 days juice fasting, as every person differently reacts to lifestyle and diet changes.

But here are the common improvements that you will probably experience at the end of your fast:

  1. Increase in energy levels
  2. Improved focus, mental clarity
  3. Improved skin and hair
  4. Weight loss
  5. Better digestion
  6. Elimination of insomnia, depression
  7. Treated autoimmune disorders

Some people who tried long-term juice fasting claimed that it helped them to get rid of chronic tiredness and depression. They suddenly had the energy to work out or go for a walk.

The skin starts to clear up and regenerate itself. Of course, in the beginning, it might get worse, but that’s a sign that the body is starting to heal.

Most people apply juice fasting mainly because they want to eliminate inflammation, which may be the cause of many other diseases and health conditions.

As you continue to fast, you will feel lighter and more energetic. In fact, many people noted that they had random bursts of energy and elevated mood throughout the day.

To help you track your results take photos of yourself before and after the juice diet. A lot of people like to do that not only to compare body shapes but skin appearance too.

Possible Side Effects

No matter how experienced you are in juice fasting, the first 3 days or even the first week (Phase 1-2) are always the hardest. You will feel a number of healing reactions, which may not be very pleasant.

Body reactions include:

  • Headache
  • Pimples, acne
  • Dizziness
  • Hunger
  • Muscle pain
  • Bad breath
  • Hunger

Starting from the second week (Phase 3), the body calms down and you feel much better. People who are overweight might continue experiencing these reactions, as a lot of toxins are removed from the body and this requires time.

During the third week (Phase 4), you will feel completely calm, as most of the healing reactions are gone. The energy levels may go up and down this time, however, you will experience mindfulness and mental clarity.

Your body will continue healing, that’s why some days you may feel light and energetic, and other days you will have a lower energy level and will want to sleep all day.

Besides all the physical reactions, you will notice emotional side-effects as well. They will mainly come in the form of emotional mood swings, insomnia, feeling restless, etc.

It is important to prepare yourself for such reactions and be aware when they happen.

In case you experience any severe form of side-effects, you should consult a doctor immediately. Juice fasting for an extended period can lead to serious health problems if not done correctly.

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Juice Diet Plan

2 cups of juice

In order to effectively start your 21 days juice fasting journey, you will need to make sure that most of your juices consist of mostly vegetables and a little fruit to add some sweetness.

One of the main rules of juicing is making 50% of your juices green vegetable-based as it will help you to avoid consuming too much sugar (containing in fruits). Also, make sure you consume fruits that are low in sugar, such as grapefruit, berries, green apples, etc. Lemons and limes can be added to any kind of weight loss juice as well, as they are neutralizing acidity in the stomach.

To help you get started with a juice cleanse, here is a sample of what your daily meal plan would look like:

Before breakfast: a cup of warm water (you can add lemon if you prefer)

Breakfast: Strawberry spinach juice
Recipe: https://www.rebootwithjoe.com/strawberry-fields-juice-recipe/

Mid-breakfast: Green juice
Recipe: https://www.rebootwithjoe.com/green-juice-to-help-lower-blood-pressure-juice-recipe/

Tea break (optional): 1 cup of herbal tea

Lunch: Beet, cucumber, spinach juice
Recipe: https://www.rebootwithjoe.com/energizing-juice-recipe/

Mid-lunch: Lettuce, green apple, lemon juice
Recipe: https://www.rebootwithjoe.com/bunnys-favorite-juice-recipe/

Dinner: Red pepper, tomato juice
Recipe: https://www.rebootwithjoe.com/thyroid-friendly-mediterranean-juice/

Before sleep (optional): 1 cup of herbal tea

How much to drink?

Juice diet

The amount of juice really depends on how often you will feel hungry. However, it is best to consume about 3 liters of juice (500-600 ml per juice) each day, 50% of which should be made of green vegetables.

Don’t forget to drink water, around 2 liters every day depending on physical activity.

In the morning, you could drink light juices for breakfast. Blueberries, strawberries, and spinach can be perfect ingredients for your morning juice, as they will help you concentrate better and keep your mind sharp. In fact, spinach is essential if you want to protect your memory from aging.

Beets, carrots, and apples are a good option for lunch. Beets help to lower blood pressure and are a good source of vitamin C. Carrots also have numerous benefits, such as preventing the risk of cancer and cardiovascular diseases. Green apples contain plenty of vitamins, and they are often used to give a pleasant flavor to juices.

For dinner, you could have celery, tomatoes and bell pepper as they contain a great set of Vitamin K, potassium and Vitamin C. Here is an excellent recipe that you can follow to make your dinner juice.

Recipe:  https://www.rebootwithjoe.com/savory-juice-recipe-for-dinner/

In general, there are no certain fruits or vegetables advised particularly for breakfast, lunch or dinner juices. You can choose whatever fruit or vegetable you want, just make sure to follow the 20/80 rule (20% fruits, 80% vegetables).

During your fast, tea and coffee are not allowed but you can have a cup of herbal tea twice a day. Your second tea time can be before sleep to help you relax.

Homemade vegetable broth is also acceptable if you feel like you need it. It is easy to digest and contains a full set of minerals essential for the body.

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Best Juice Cleanse Tips

cleanse juices

The 21 days juice fasting requires a lot of preparation and commitment. To help you easily go through your 21 days juice cleanse, here are several essential tips before, during and after your juice fast.

Tip #1 Plan

Before you get started, make sure you have a rough plan for your weekly juices. So, at the beginning of every week, you will need to buy and prepare all the ingredients necessary for juicing.

Tip #2 Listen to your body

As it was mentioned many times, every one of us has a different reaction to fasting.

So, make sure you notice the signs your body is giving to you during the juice cleanse and follow them.

If you feel tired, then stay at home and don’t do any physical activities that day. And if you feel well and have energy, proceed with your usual daily routine.

Tip #3 Know what you’re drinking

During the juice cleanse, many questions may arise concerning juicing methods, store-bought juices, etc.

There are 3 main ways of juicing: cold-pressed, blended, and fresh-squeezed. In reality, there is no right or wrong method, it only depends on what you want to achieve in your juice fast.

Regular, freshly squeezed juice is made with an ordinary juicer, you might probably have at home.

Its fast-spinning blades extract the juices. This is a cheaper and faster method compared to cold-press juicers.

The only drawback here is that the spinning blades create heat, which breaks down essential nutrients and enzymes in the fruits and vegetables.

Also, the juice can’t be stored for a long time.

Cold-pressed juicers, on the other hands, crush the ingredients and squeeze the juices.

Plus, you can store the juices for later. However, it takes longer to get the juice ready and the machine is more expensive.

These two methods remove the pulp and fiber and you simply get 100% juice.

It is done to help your digestive system to take a break as it spends much less energy to process pure juice rather than juice with pulp.

If you don’t want to throw out the fiber, then blending the fruits and vegetables can be an option for you.

In case your juice is too concentrated, you can always add some water to dilute it before you consume it.

It is best to make your own juice for fasting, however, if you don’t have time, you can find fresh juices in stores. Make sure they don’t have artificial compounds or sugar in them.

Tip #4 Breaking the fast with care

Breaking the fast correctly is essential, as your body is getting used to normal solid food.

You shouldn’t rush, hence start by introducing solid foods slowly each day.

For example, start your breakfast with a bowl of fresh fruits or a simple salad with lemon dressing.

You can continue having a salad for lunch. Add some fermented foods to be able to digest easily. For dinner, steamed vegetables can be a perfect choice.

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21 Days Juice Fasting Recipes

Recipe #1 Sweet lime, celery spinach juice recipe

green juice


  • 80 g of spinach leaves
  • 45 g of sweet lime
  • 2 celery stalks
  • Lime (optional)

Instructions: Roughly cut the ingredients and remove fibrous parts. Squeeze in the juicer.

Recipe #2 Kiwi and beetroot juice recipe

Purple juices


  • 100 g of beetroot
  • 1 kiwi
  • 2 celery stalks
  • Lemon (optional)

Instructions: Peel the kiwi and chop. Add kiwi, celery, and beetroot in the juicer and squeeze. Add a few drops of lemon juice for flavor.

Recipe #3 Cucumber, cabbage, mango juice recipe

people cheering with juices


  • 300 g of cucumber
  • 200 g of mango
  • 2 spinach leaves
  • 270 g of cabbage
  • Some parsley

Instructions: Put all ingredients in the juicer and you’re done.

You can find various easy juice recipes here.

Supplements and Fasting

When you start a juice cleanse, you are basically consuming a high number of vitamins and nutrients that you probably, wouldn’t be able to get from your normal diet.

And, if you are doing long-term juice cleanse, make sure to include plant-based protein sources in your juices, such as spirulina and chia seeds.

In addition, it is not advised to take non-prescription supplements during your cleanse. However, if you do have some kind of deficiency and your doctor has prescribed a supplement, then you should continue taking them.

Recommended reading:

Who shouldn’t do this diet?

The 21 days juice fasting is a pretty long period. Therefore, you should take precautions to avoid any severe health damage.

People who shouldn’t do juice fasting:

  • Pregnant and/or nursing women
  • People using prescribed medications
  • People under treatments and/or with severe health conditions

In any case, consult on your health status before attempting this diet.


This content has been Fact-Checked by a Certified Nutritionist in our Publishing Team. Learn more here.

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