Counting calories during a juice cleanse? Here's how much is in your glass

A juice cleanse provides significantly less energy than a normal day. According to its nutritional information, the BESSERE SAFTKUR PLUS contains 731 to 885 kilocalories per day, distributed across juices, shots, and kombucha. For comparison, the German Nutrition Society (DGE) lists reference values for adults between 25 and 51 years of age with little physical activity. Women are at around 1,800 kilocalories, men at 2,300 (DGE, as of 2015).

However, the calorie count alone says little about quality. Two cleanses with the same 800 kilocalories can be completely different. It depends on whether the energy comes from sweet fruit or vegetables. When it comes to sugar, it determines whether your blood sugar remains calm throughout the day or fluctuates. Our article does a juice cleanse really do anything honestly assesses what such a cleanse can actually achieve.

Many cleanses rely on four to six juices a day, while others combine fewer juices with shots and kombucha. Anyone adding up calories during a juice cleanse starts with the individual bottle. According to the nutritional table, the green "Supergreen" contains 21 kilocalories per 100 milliliters, i.e., around 105 kilocalories per bottle. The "Radiator" with apple, sweet potato, and carrot reaches 50 kilocalories per 100 milliliters, so about 250 per bottle. A day with predominantly green juices is therefore at the lower end of the range, while a day with fruity varieties is at the upper end.

This results in the calorie deficit that every cleanse entails. If you normally consume around 2,000 kilocalories and 800 during the cleanse, you save about 1,200 per day. Over three days, that is around 3,600 kilocalories that the body compensates for from its reserves. This is the core of every juice cleanse. That is why it is a conscious break for a few days and not a long-term diet.

An example makes it tangible. Lena usually eats three meals and two snacks, totaling about 1,900 kilocalories. In her three-day cleanse with juices, shots, and kombucha, her day totals around 800, and her hunger is greatest on the second afternoon. Because she knew this beforehand, she keeps that exact afternoon free. How long an initial cleanse makes sense is explained in our article Juice cleanse 3 days, 5 or 7.

Sugar is the real sticking point. Pure fruit juices provide a lot of fructose, and that doesn't count as harmless just because it comes from fruit. The World Health Organization (WHO) explicitly classifies sugar from fruit juices as free sugars and recommends consuming less than ten percent of daily energy from them (WHO, 2015). The consumer center translates this for adults into around 50 grams per day (consumer center, as of 2026).

A simple comparison shows how quickly this amount is reached. A 200-milliliter glass of apple juice provides around 92 kilocalories, a lemonade in the same amount about 85 (Federal Center for Nutrition, 2023). Energetically, there is little difference between the two. A cleanse consisting predominantly of fruit can thus become a sugar bomb over the course of the day, even if it is cold-pressed and produced in organic quality.

Added to this is a finding from research that provides clues but is not yet a definitive conclusion. A small study from the USA had healthy adults drink only juice for three days. Two comparison groups received juice with solid food or only whole-food plant-based nutrition. In the pure juice group, bacteria associated with inflammatory processes increased in the mouth and gut (US study, 2025). The researchers explain this by the high amount of sugar and the lack of fiber. One more reason to take a close look at the sugar content of a cleanse.

Many start a cleanse to lose weight, and the scale seems to prove them right. After just two days, it shows significantly less. However, this weight hardly comes from fat at first. In the first 24 to 48 hours, the body empties its glycogen stores in the liver and muscles, i.e., its short-term sugar reserve. Water is attached to every gram of it. In addition, the body excretes more water via the kidneys because hardly any salt is coming in and insulin levels drop (Swiss Journal of Nutritional Medicine, 2022). The quick effect on the scale is therefore primarily water loss.

Only after that does the body rely more heavily on its fat reserves. In a short three-day cleanse, this proportion is manageable. As soon as you eat normally again, the stores fill up again along with water. If you return to old habits after the cleanse, the scale will show almost the same number after a week. That is not a failure; it is physiology.

That is why it is worth viewing calories during a juice cleanse not as a tool for weight loss, but as a framework for a break. The value of the days lies in seeing your habits—the afternoon hunger, reaching for sweets, eating on the side. If you take this observation with you into the post-cleanse days, you will benefit more from it than from any number on a scale.