Most people that come to me for advice on how to get in shape, almost always underestimate the value of water. Water cleanses your body from toxins and pollutants that would get you sick. Water is needed for all of the complex chemical reactions that your body needs to perform on a daily basis. Processes such as energy production, muscle building, and fat burning require water. A lack of water would interrupt all of these processes.
Water helps lubricate the joints.
When the outside temperature is up, water serves as a coolant to bring the body temperature down to where it is supposed to be. Water helps control your appetite. Sometimes when you feel hungry after a good meal this sensation indicates a lack of water. Drinking water at that time would take the craving away. Cold water increases your metabolism.