While low calorie diets can result in weight loss in the first few weeks and months of starting the diet, the majority of the weight lost is not fat. This is because low calorie diets do not provide sufficient energy to fuel the body's basic functions such as breathing, circulation, and digestion etc. In order to provide the fuel to keep itself alive, the body breaks down muscle tissue, which is easily convertible into glucose, and is easier to access and break down into energy than fat. In effect, low calorie diets reduce the amount of lean muscle tissue in the body, which has a knock-on effect of reducing the basal metabolic rate. Lean muscle tissue is metabolically active, meaning that the more lean muscle tissue an individual has, the more calories are burned. The reduction in lean muscle tissue also reduces the body's ability to burn fat. When you finally lose the weight and start eating normally, your body can no longer burn calories at the rate it did before your diet because you now have less lean muscle tissue! You become locked in a vicious cycle of dieting and weight gain - simply because your body breaks down muscle for glucose before it breaks down fat. Although you might only end up gaining back the original weight you lost, you are will end up fatter because you have lost lean muscle tissue and gained back fat. The result of the loss of lean muscle tisssue and the weight gain arising from it is termed the Yo-Yo effect. Many dieters, when finding that they have regained the weight they have lost, embark on another diet, which plunges them further into lean muscle tissue loss. So, what is the solution to permanent weight loss? To lose weight effectively, you need to consume enough energy to burn fat, and eat the right foods to maintain your level of lean muscle tissue. A sensible balance of a healthy diet and moderate exercise is more effective in achieving a permanent weight loss than low-calorie diets . Here is an information that might be useful: theweightlossmiracle.com