Juice fasting or water fasting?
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Time to read 6 min
Introduction
Juice fasting or water fasting, which approach is right for you? Both involve going without solid food for a few days, but they’re worlds apart. With one, you drink only water and tea; with the other, you get some energy from juices. This changes how the days feel and how much supervision you need.
When comparing juice fasting and water fasting, we look at energy, muscles, safety and daily life. You’ll learn the strengths and weaknesses of both approaches and which one we recommend for getting started.
Good to know
With water fasting, you consume no calories. Classic Buchinger therapeutic fasting provides 250 to 500 kilocalories a day. A juice cleanse like BESSERE SAFTKUR PLUS provides 731 to 885, according to its nutrition information.
Juice fasting or water fasting? The short answer
For most healthy people, juice fasting is an easier way to get started. You get some energy, vitamins and fluids, and can fit the fast into a quiet daily routine. Water fasting is the strictest form of fasting. Because of the risks, it requires medical supervision and is better suited to a clinic than a regular workweek. So when it comes to juice fasting versus water fasting, it’s less about which is better or worse and more about your circumstances and experience.
In between is Buchinger therapeutic fasting, which includes juice, broth and a little honey. The Medical Association for Therapeutic Fasting and Nutrition (ÄGHE) recommends no more than around 500 kilocalories a day (ÄGHE, 2025).
| Feature | Juice fasting | Water fasting |
|---|---|---|
| Energy per day | About 500 to 900 kilocalories | None |
| What you drink | Fruit and vegetable juices, water, tea | Only water and unsweetened tea |
| Supervision | Possible for healthy people on their own; consult a doctor if you have a pre-existing condition | Medical supervision recommended |
| Daily life | Quiet days are enough | A quiet place or a clinic |
| Typical duration | Three to seven days | Several days under supervision |
| Who it's for | Beginners and experienced fasters | Experienced fasters with supervision |
What matters in the comparison
Energy and nutrients
The clearest difference is energy. With water fasting, your body relies entirely on its reserves. In the first 24 to 48 hours, it uses up its glycogen stores, then switches more heavily to its fat reserves (Swiss medical journal, 2022). With juice fasting, you get some sugar from the juices throughout the day, along with vitamins and minerals. This makes the transition gentler. The German Nutrition Society (DGE) sees this as the key difference. During therapeutic fasting, the body still gets a little energy; during total fasting, it gets none (DGE, 2018).
Our take upfront 👈
If you’re fasting for the first time, try a three-day juice fast. Water fasting isn’t for beginners; it’s for experienced fasters under medical supervision.
Muscle and protein
With juice fasting or water fasting, this is the point many comparisons leave out. If you eat nothing, you lose more than just fat. A 2024 review analyzed eight studies on longer water fasts. Around two-thirds of the weight lost was water and muscle, and only one-third was fat (Ezpeleta et al., 2024). At the start of a total fast, the body breaks down up to 75 grams of protein a day (Swiss medical journal, 2022). There are hardly any measurements like this for juice cleanses. That’s another reason why short cleanses are the safer choice.
Supervision and safety
The same paper notes common complaints during water fasting, such as poor sleep, fatigue, dizziness, a dry mouth, and headaches. Serious consequences, such as acidic blood or water in the tissues, were rare (Ezpeleta et al., 2024). A large study of 1,422 people who fasted shows how much supervision matters. They received daily medical supervision and 200 to 250 kilocalories a day. Serious side effects occurred in less than one percent of participants (Wilhelmi de Toledo et al., 2019). That’s why water fasting should be done under experienced supervision. Juice fasting also has its limits. Pregnancy, breastfeeding, being underweight, eating disorders, and serious liver or kidney disease rule out any kind of fasting (ÄGHE, 2025). If you take medication, never fast alone. Find out exactly who a juice cleanse is suitable for in our article.
A direct comparison of both approaches
Water fasting, advantages and disadvantages
Anyone weighing up juice fasting or water fasting should understand the stricter option. Water fasting is the oldest and strictest form of fasting. You drink only water and unsweetened herbal tea and consume no calories. In clinics, it is done under medical supervision with regular checkups. Its appeal lies in its simplicity; the price is the strain it puts on the body.
Advantages:
- As simple as it gets: You need nothing but water and tea.
- No calories: Weight drops faster in the first few days than with any other form of fasting.
- Clear rules: There’s no question about what you can and can’t drink.
- Well studied: There are more studies on supervised fasting than on juice cleanses.
Disadvantages:
- Significant muscle loss: Around two-thirds of the weight you lose is water and muscle.
- Common complaints: Dizziness, fatigue, and poor sleep are common.
- Requires supervision: It’s not advisable for many people without medical supervision.
- Hardly practical: Work and appointments don’t mix well with zero calories.
Juice fasting: advantages and disadvantages
During a juice fast, you drink several juices throughout the day, along with water and tea. Whether juice fasting or water fasting feels easier usually becomes clear on the second day. That’s where a juice cleanse has a clear advantage. But it has a downside you should know about. Juices contain sugar and hardly any fiber. A small study found changes in the oral and gut microbiomes after three days of drinking only juice. The researchers believe the sugar and lack of fiber are the reason (US study, 2025). This points to short cleanses based on vegetables.
Advantages:
- Gentler start: A little energy makes the first few days much easier.
- Vitamins and fluids: Vegetable juices provide vitamins that are missing during water fasting.
- Fits into everyday life: You can work as usual on quiet days.
- Can be done on your own: Healthy adults with no pre-existing conditions don’t need a clinic.
Disadvantages:
- Sugar in a glass: Fruit-heavy juices contain a lot of fruit sugar, so vegetables are essential.
- Hardly any fiber: It stays in the pulp when the juice is pressed.
- Less research: Juice cleanses have been studied far less than medically supervised fasting.
- No shortcut: Some of the weight comes back after the cleanse, too.
Find out how much sugar different juices contain in our article on calories and sugar in a juice cleanse.
Juice fasting or water fasting at a glance
Water fasting is the strictest form and should be medically supervised
Around two-thirds of the weight lost during water fasting is water and muscle
Juice fasting is gentler and suits quieter days
When juice fasting, the vegetable content determines the sugar level
For beginners, a vegetable-based juice cleanse for three days
What's the difference between juice fasting and water fasting?
When water fasting, you drink only water and tea and consume no calories. Juice fasting includes juices that provide some energy, vitamins, and minerals.
Which is better, juice fasting or water fasting?
For beginners, juice fasting is usually the better choice because it's gentler and easier to fit into everyday life. Water fasting is stricter and should be medically supervised.
Do you lose muscle when water fasting?
Yes. Studies on longer water fasts found that around two-thirds of the weight lost was water and muscle.
Do you lose weight faster with water fasting?
In the short term, yes, because you take in no calories. However, much of the weight lost is water and muscle mass, and the weight often comes back if you don't make changes afterward.
Can I do a water fast on my own?
This is not advisable for many people. Water fasting should be medically supervised, especially if you take medication or have pre-existing conditions.
Are juice cleanses too sweet?
That depends on the juices. Juice cleanses heavy on fruit contain a lot of fructose, while those with more vegetables contain significantly less. So check the ingredients list.
Who should not fast at all?
Fasting is not suitable during pregnancy or breastfeeding, if you are underweight, have an eating disorder, or have severe liver or kidney disease.
The author: David J Kugler
Founder and managing director of DALUMA. Writes about nutrition, juice cleanses, and holistic self-care.
