A juice cleanse is a highly restrictive, short-term dietary regimen that exclusively involves consuming fruit and vegetable juices, typically for a few days up to a week. People often undertake this liquid diet hoping to achieve rapid weight loss and a sense of internal “detoxification.” The practice works by dramatically reducing caloric intake, forcing the body to seek alternative energy sources. While the scale may show a significant drop after five days, the physiological mechanisms driving this change are temporary and distinct from sustainable fat loss.
Expected Weight Loss Range After 5 Days
A person completing a 5-day juice cleanse can realistically expect to see a weight reduction falling within a range of approximately 5 to 10 pounds. This number is individualized, depending on a person’s starting weight, metabolism, and the calorie content of the juices consumed. The typical juice cleanse provides a caloric intake significantly below maintenance needs, creating a substantial energy deficit over the five days. This deficit is the primary driver of the initial rapid weight reduction observed on the scale.
Why the Initial Weight Loss Happens
The rapid weight loss seen during the first few days of a juice cleanse is not primarily due to the loss of body fat, but rather the depletion of stored carbohydrates and a subsequent loss of water. When the body enters severe calorie restriction, it first accesses its reserve of glycogen, the stored form of glucose found in the liver and muscles. Each gram of glycogen is bound to approximately three to four grams of water molecules.
As the body uses these glycogen stores for energy, the associated water is released and excreted through urine, leading to a quick drop in total body weight. The absence of solid food and dietary fiber also reduces the volume of intestinal contents, contributing to a lighter feeling and a flatter stomach appearance. The cleanse’s low-sodium nature encourages the body to shed excess extracellular fluid.
While the body does begin to burn a small amount of fat to meet energy demands, the majority of the scale change is attributable to the loss of water and gut contents, not adipose tissue. This short time frame is insufficient for a significant reduction in body fat.
Post-Cleanse Weight Regain
A substantial portion of the weight lost during the five-day cleanse is typically regained shortly after resuming normal eating habits. Studies indicate that a significant percentage of this initial weight reduction, sometimes up to 72%, returns within just a few days of reintroducing solid food. This swift rebound occurs because the body quickly works to replenish the depleted glycogen and water reserves.
When carbohydrates and sodium are reintroduced, the body stores glycogen in the muscles and liver once more. Since glycogen requires water for storage, the body retains the necessary fluid, causing the scale weight to increase rapidly. The digestive system also refills with food mass, further contributing to the weight gain. Sustainable fat loss requires a consistent, long-term caloric deficit, making the cleanse an ineffective strategy for lasting change.
Important Safety and Health Considerations
Restricting one’s diet to only juice for five days can lead to common side effects, including fatigue, headaches, dizziness, and irritability, often resulting from low blood sugar and insufficient calorie intake. Juices frequently lack adequate amounts of protein, fiber, and healthy fats, which are fundamental for maintaining muscle mass and supporting satiety. The deficiency of protein can lead to the breakdown of lean muscle tissue for energy, which is counterproductive to a healthy metabolism.
Juice cleanses can also pose risks for individuals with pre-existing medical conditions. Those with diabetes or blood sugar regulation issues should avoid cleanses due to the high concentration of natural sugars in fruit-based juices, which can cause significant blood sugar spikes and crashes. People with kidney disease are also advised against them because the high intake of certain nutrients, such as potassium and oxalate, can place undue strain on compromised kidneys. Consultation with a healthcare provider is prudent before starting any restrictive dietary regimen.