The adult human body is made up of roughly 60% water, so it’s important to replenish water that is lost naturally throughout the day as we sweat, visit the restroom, and even breathe. All fluids can help maintain a proper water balance in your body, but water — plain or sparkling — does so without providing extra calories or added sugar, so it’s a great idea to make it your first choice for daily hydration. maintain a proper water balance in your body, but water — still or sparkling — does so without providing extra calories or added sugar, so it’s a great idea to make it your first choice for daily hydration.