I've done a couple of long endurance events and have a few tips:
Drink little and very often. You can keep going without food if you really have to, but if you dehydrate you'll grind to a halt. Consider getting a 'bladder' system like a Platypus or similar.
Energy (carbohydrate) drink is good, quite dilute though, as the doggy says. You might find that after many hours of drinking it you can't stomach it anymore. Some people find that certain energy drinks upset their stomach, best to try out before the event.
Don't expect to be able to eat sweet food all the time. My stomach rebels at the thought of more sweet stuff after a while - take plenty of savoury things.
Defizzed coke is great for the last couple of hours, assuming you don't have to carry it for the whole event.
If you aren't stopping to camp, do you really need to carry 40kgs? What event is it?