How much water is actually produced by a human on an average day of metabolism?

Dave - Well, I can acknowledge a contribution from our wonderful friend, the internet here. There's a book by Paul Insell, Elaine Turner and Don Ross, Discovering Nutrition. We just had a quick look in there and their stated figure is about a third of a litre per day is the amount of water that your body makes just through metabolising, just by burning sugar because the equation is glucose: C6H12O6. If you burn that using six molecules of oxygen: plus 6 O2, this goes to 6 molecules of carbon dioxide: six CO2 plus 6 H2O, six water molecules, and that all adds up to about a third of a litre a day which is why you get some of the water that you need from actually your own metabolism.