An adult needs approximately 2 to 3 litres of liquids a day. Coca-Cola, coffee and strong tea should not be taken into account, because they act as diuretics, increase the function of the kidneys and cause loss of water. In addition, drinks with a lot of mineral salts, such as some mineral waters and lemonades, increase thirst instead of extinguishing them. Salt-free mineral waters are the healthiest and best quench thirst.
-“Home Medical Guide”