Whether your goals are to lose weight, add muscle or just maintain a fit and young-looking physique, it is extremely important to be sure to stay hydrated by drinking water.  That's just plain old simple water.  No carbonation, no artificial sweeteners, no electrolyte and glucose loaded beverages.   Just drink water and you will see the gains you are looking to achieve without bloating or overloading on unnecessary calories or chemicals.  When you are exercising, it is advisable to consume a minimum of 8 ounces of water every 15 minutes to replace what you sweat out and maintain a healthy level of hydration.