Whilst watching the TDF; I keep hearing these little factoids come out. Interesting one came up yesterday and that was with regard to Fluid loss.

Whatever weight you have lost in the day- If you do not replace half that weight in fluid within 1 1/2 hours of finishing the ride- You will not be finishing the TDF.
In other words- lose 4 lbs weight on the day and you have to replace 2 lbs of that with fluid quickly- otherwise it will affect your riding in the following days.

Worked in my favour today- Lost two lbs weight- despite drinking 2 litres of water and a large coffee on the ride- and eating a large Brie and Bacon baguette- so had to open up another bottle of Chilled white bordeaux to recover.