12 Hour Ride - nutrition advice

[NATURAL ANKLING]

https://en.wikipedia.org/wiki/Perspiration
"Maximum sweat rates of an adult can be up to 2–4 liters per hour or 10–14 liters per day"

Really helpful post and link, thanks. I hadn't quite considered just how much fluids I will need to be taking on - hence why I came on here - there always others with more experience!!

One summer I did a 200K hot and humid, I was wearing a standard cotton t shirt, when I got home I could stand it up on the table no joke.
I drank in excess of 14 litres that day, whole day.
Also be careful about drinking TOO MUCH water especially with no food / whatever salts, it will have an adverse effect, you will feels sick.....
1/2 - 1 L max an our with food, is a start.
Like I said try and use some scales during ride.

https://en.wikipedia.org/wiki/Water_intoxication
"Overexertion and heat stress[edit]
Any activity or situation that promotes heavy sweating can lead to water intoxication when water is consumed to replace lost fluids. Persons working in extreme heat and/or humidity for long periods must take care to drink and eat in ways that help to maintain electrolyte balance."

Sort of torture-
"In addition, water cure, a method of torture in which the victim is forced to consume excessive amounts of water, can cause water intoxication.
Water, just like any other substance, can be considered a poison when over-consumed in a specific period of time. Water intoxication mostly occurs when water is being consumed in a high quantity without adequate electrolyte intake"

[Saulius Ruzgys]

I take 4l of water bananas and protein bars and eat every hour or so works for me very well

[Vorpal]

I used to work occasionally in the Arizona desert in temperatures exceeding 40 degrees C. When exerting ourselves, we were advised that we should drink at least a 1/2 litre of water every hour, and have electrolyte drops or tablets with every 3rd or 4th half litre. We were also told that individuals vary, and some people might need twice as much water. Some of the people I worked with marked their water bottles or used rubber bands to remember the electrolytes.

I'm not too sure about Wikipedia's 2 - 4 litres per hour. 2 litres per hour is pretty extreme. I don't have access to all of the sources referenced, but the ones I do indicate that the maximum recorded in experiments is around 1.8 - 2 litres per hour. That was for extreme exertion in high temperatures by people who are not heat adapted.