It all depends on where you are going, at least that is the major factor I consider when planning meals for a trip. In the Uintas, Winds or Alaska (I frequent the Arrigetch Peaks region) I have had no problem landing 50% of my calories in convenient, yummy, scale-covered packaging. At other venues, like the northern Cascades or Sierra Nevada (Tahoe to Yosemite) I find the finned denizens to be much more selective feeders. I can catch them, but it is more time consuming. Out east (Smokies for example), the snobby little fish act like I am trying to eat them or something and avoid my flies like a plague ship.
I will also add something to this calories/fish debate. Eight ounces of trout meat down the hatch will provide at least 400 calories. Second, those are highly digestible calories your body will extract efficiently. Consuming 400 calories of re-hydrated yuck will yield significantly less useable energy - in other words a lot more re-hydrated food will pass straight through you.
Finally - in context of the original post - on a three day/two night trip into a fishy location, be bold - take a some rice, a big tube of PNB, some trail mix and a nice assortment of flies. If you don't catch fish what’s the worst that could happen? Maybe you will be driven to improve your fishing......