IMO you should always start with your glycogen carb stores topped up and then you are good for up to a few hours without refueling depending on intensity.From there my refueling is determined by intensity and duration.For quick bursts of high intensity I will go with mostly high glycemic refined carbs(honey etc.) and more sustained high intensity still mostly carbs but mix in some easily digested lower glycemic less refined simple carbs
(dried apricots,other fruit +honey etc.).For lower intensity I will go with a combination of lower glycemic more complex carbs plus fat (and a small/moderate amount of protein)with the % fat increasing as the intensity decreases(dried apricots,complex carb based energy bar +pitaschios,dried coconut etc.).When I am in a range where I'm utilizing a large percentage of fat for fuel I find including some fat intake for fuel helps .Keep in mind the protein,fat and complex /low glycemic carb choices need to be made with what you can easily digest in mind . As the duration of the lower intensity increases I may go back towards more refined sources of the above focusing on whatever I can digest.
So I guess I increase the protein somewhat as the intensity decreases and the duration increases but my objectives include avoiding muscle loss not just pure performance.Still I generally save the high protein intake for the post exercise recovery phase.