Updated: October 2026
In short: Therapeutic fasting is the strictest form: about 250 to 500 kcal per day over 7 to 10 days, ideally with supervision. A Juice Cleanse is milder and usually lasts 1 to 7 days. Intermittent fasting is an ongoing rhythm rather than a cleanse. Which method suits you depends on your goal, your daily life and your health. As of: October 2026.
Three methods, three philosophies. Instead of individual descriptions, here you get a direct comparison with numbers and a decision aid.
What's the difference between Juice Cleanse, therapeutic fasting and intermittent fasting?
Mainly duration, energy intake and structure. Therapeutic fasting and Juice Cleanses are time-limited cleanses, while intermittent fasting is a recurring eating rhythm. The table shows the key differences. The therapeutic fasting figures come from the DGE (German Nutrition Society), the Juice Cleanse figures from our product data.
| Therapeutic fasting | Juice Cleanse (frank.) | Intermittent fasting | |
|---|---|---|---|
| Duration | 7 to 10 days plus lead-in and build-up days | 1, 3, 5 or 7 days | Ongoing, weekly |
| Energy per day | approx. 250 to 500 kcal | approx. 650 to 930 kcal depending on variant | Normal on eating days, on 5:2 approx. 25% on two days |
| What you eat | Broth, juices, honey, tea | 6 juices per day | Normal food in the eating window |
| Supervision | Recommended by a doctor | Doable on your own, heed the note | Doable on your own |
| Effort | High | Medium | Low to medium |
Remember: the less energy, the more important medical supervision is.
How does therapeutic fasting work?
With very little energy over a week or longer. The DGE refers to the recommendation of the German medical society for therapeutic fasting: 7 to 10 days as standard, one lead-in day beforehand and three days afterwards to normalise eating habits. Each day you take in about 250 to 500 kcal from vegetable broth, fruit and vegetable juices and honey, plus at least 2.5 litres of tea or water.
The DGE stresses that success depends decisively on supervision by experienced fasting doctors or trained fasting leaders, especially if medication needs to be adjusted. The consumer advice centre (Verbraucherzentrale) advises that even healthy people shouldn't fast completely for longer than a week. More on this in the article What Is Fasting?
How does a Juice Cleanse work?
For a few days, you replace all meals with juices. With the frank. Juice Cleanse, you drink six juices (330 ml) per cleanse day, cold-pressed, vegan and with no added sugar. Depending on the variant, that's approx. 650 to 930 kcal. We also recommend at least one litre of still water or herbal tea.
In energy terms, a Juice Cleanse is therefore above classic therapeutic fasting and less demanding. It still needs preparation and a gentle return to eating, as described in the article Juice Cleanse Guide . It is not suitable for pregnant or breastfeeding women, children and people with a weakened immune system. If you take medication or are ill, ask your doctor first.
How does intermittent fasting work?
You alternate between eating and fasting periods instead of doing a cleanse. The DGE lists as variants the 5:2 principle (about 25% of energy on two days), alternate-day fasting, the two-day diet with a maximum of 650 kcal on two consecutive days and skipping dinner two to three times a week. The AOK (a German health insurer) also describes the popular 16:8, with 16 hours of fasting and an eight-hour eating window, for example from 12 to 8 pm.
According to the DGE, the evidence is limited and not clear-cut. In comparisons, intermittent fasting for weight loss turned out roughly equivalent to continuous calorie reduction. With alternate-day fasting, the dropout rate was higher at 38% than with daily calorie reduction at 29%. You'll find an overview of the rules under What Is Intermittent Fasting and What Are the Rules?
Which method suits which type?
That depends on goal, time and health. The matching is our own assessment and not medical advice.
| Your situation | More suitable |
|---|---|
| I want a short reset, with little cooking | Juice Cleanse (3 to 5 days) |
| I want to change something long term in my daily life | Intermittent fasting (16:8 or 5:2) |
| I have a pre-existing condition and want to fast for longer | Therapeutic fasting with medical supervision |
| I work on the move a lot | Intermittent fasting, flexible |
| I have little time for preparation | Intermittent fasting or 1-day Juice Cleanse |
| I like to eat socially and regularly with family | Intermittent fasting in the eating window |
You can get a personal suggestion from the Cleanse Quiz. You can learn more about how the cleanses work in the article Types of Fasting.
Can you combine the methods?
Yes, in a sensible order. Many people start with a short Juice Cleanse and then move into an intermittent fasting rhythm. That way you use the reset and afterwards have a structure that fits into your daily life. This is a suggestion from experience and not a study recommendation.
Gaps matter: after a Juice Cleanse, you need a few days of normal food before moving into a fasting rhythm. You can read more about frequency in the article How Often Should You Do a Juice Cleanse. Combining therapeutic fasting and intermittent fasting at the same time doesn't make sense, because both strongly limit energy.
An example for six weeks: week 1 normal food with less coffee and alcohol, week 2 a 3-day Juice Cleanse with two build-up days, weeks 3 to 6 a 16:8 rhythm with an eating window from 12 to 8 pm. After four weeks, you check whether the rhythm fits your daily life, and adjust it. If you notice that 16:8 doesn't suit you, try 14:10 or two days of 5:2 per week before giving up entirely.
Who shouldn't start any of the methods without checking first?
Pregnant and breastfeeding women, people with eating disorders, underweight, diabetes, low blood pressure or metabolic conditions. The AOK also lists older people and people with pre-existing conditions, cancer patients in active treatment and people taking blood thinners or antidepressants. The consumer advice centre generally recommends getting medical advice before fasting, especially if you take regular medication or insulin.
If you have dizziness, a racing heart, severe weakness or circulation problems, stop. The DGE also notes that many intermittent fasting concepts give no guidance on food choice and therefore don't automatically lead to a better diet. The same applies to cleanses: if you drink juice for three days and then eat as before, you've mainly taken a break. So plan ahead what should concretely change in your daily life afterwards, for example less sugar, more vegetables or fixed meal times. That turns each of the three methods into more than a one-off event.
Pairs well with frank.
If you'd like to try the Juice Cleanse, you'll find in the Juice Cleanse collection cleanses from one to seven days. The 3-day version starts at 99.75 EUR (as of October 2026).
You might also like
- Juice Cleanse vs. 5:2 Intermittent Fasting: Which Suits Me Better?
- Types of Fasting: Which Is Right for Me?
- What Is Intermittent Fasting and What Are the Rules?
Frequently asked questions about Juice Cleanse, therapeutic fasting or intermittent fasting
Is a Juice Cleanse the same as therapeutic fasting?
No. According to the DGE, therapeutic fasting is around 250 to 500 kcal daily over 7 to 10 days. A Juice Cleanse delivers more energy and usually lasts for less time.
What's easier to stick with: Juice Cleanse or intermittent fasting?
A Juice Cleanse is short and clear. Intermittent fasting is flexible but takes discipline over weeks. Both are individual.
Who shouldn't fast?
Pregnant and breastfeeding women, people with eating disorders and many people with pre-existing conditions. Talk to your doctor first.
Can I lose weight with all three methods?
Yes, if you take in less energy overall. The DGE sees intermittent fasting for weight loss as roughly equivalent to continuous calorie reduction.
What is the maximum length of time you can fast?
The consumer advice centre advises that even healthy people shouldn't fast completely for longer than a week. Longer periods belong under medical supervision.
Note: This article is for general information and does not replace medical or therapeutic advice. If you have symptoms or pre-existing conditions, are pregnant or take medication, please speak to your doctor first.
