Many people who go through a cleanse lose significant amounts of unwanted weight in the process. While some purification programs do cause muscle loss, if the cleanse is done carefully, weight lost will consist solely of fat and mucus, not muscle. In fact, it is quite possible to build lean muscle, though muscle weighs more than fat, so the scale may show less weight loss. Either way, you will feel leaner and fitter afterwards.
In a toxic environment, the immune system struggles to fight off disease and you may get sick frequently and have trouble recovering from illness. Cleansing your system removes the overload of toxins that inhibit the immune system and allow it to work more efficiently.
Your physical body does not exist independent of your emotional and mental states. In fact, your thoughts and feelings have tremendous impact on your health. When you have negative thoughts, your emotional state suffers and eventually your physical state will as well. When you replace negative thoughts with positive thoughts, your emotional and physical health will both begin to improve. The reverse is also true. The body stores up all those negative thoughts and emotions. When toxins are cleared away, the negativity will be cleared away with them.