VLCDs appear to be more effective than behavioral weight loss programs or other diets, achieving approximately more weight loss at 1 year and greater sustained weight loss after several years. When used in routine care, there is evidence that VLCDs achieve average weight loss at 1 year around or about 4% more weight loss over the short term. VLCDs can achieve higher short-term weight loss compared to other more modest or gradual calorie restricted diets, and the maintained long-term weight loss is similar or greater. VLCDs were shown to reduce lean body mass. Combining VLCD with other obesity therapies yield more effective results in weight loss. Low-calorie and very-low-calorie diets may produce faster weight loss within the first 1–2 weeks of starting compared to other diets, but this superficially faster loss is due to glycogen depletion and water loss in the lean body mass and is regained quickly afterward.