Water is very important for both health and performance. It keeps your organs functioning properly, removes toxins from your body, reduces extra sodium in your body, and hydrates your muscle cells. Water even helps to free fat stores on your body so they are burned off as energy. Being dehydrated can cause a major decrease in your performance.
Your body may also register dehydration as hunger, so staying properly hydrated can also help keep you trim. In fact, studies have shown that drinking more water can help you lose more weight.