metabolic water production
Water released into the tissues during the metabolism of foodstuffs. For example, during cellular respiration water is a by-product of the oxidation of carbohydrate and free fatty acids. In addition, water chemically bound to glycogen is released when glycogen is oxidized. Approximately 3 g of water is released for each gram of glycogen broken down. Metabolic water production can contribute significantly to an athletes fluid needs during exercise so that the ideal volume of fluid replacement is somewhat less than the total sweat loss.