Deciding on what is suitable food for lumping up and down rivers is an important consideration. Fuel for your body! Food will make up a significant proportion of the weight of your pack. You will always need more than you think. This is for two reasons: one is that the food's weight alone is incentive to eat it ('I know, if I eat it, I won't have to carry it!') and the other is that your body is going to demand far more food than normal (you're climbing mountains for crissakes!).
Food is a science. I say this because every piece of nutritional advice I have read tells me so. You want carbohydrates. And many of them.
Choose your food from the following lists.
Evening meal items
Tasty two minute noodles
Rice and pasta
Cheese and salami or just cheese
Salt and pepper
OR just choose Chilli-beans; Jim Curry and I lived on them for two months will no noticeable ill effects, well none without a match
Tea / coffee
Dried fruit and nuts (I can get through 1lb per day)
Cabin bread or crackers
Jim Curry and I discovered that red wine and stuffed olives can be a useful snack
Dehydrated animal food, or something else you can't stand, like vegemite (yes one season I carried a bag of cat biscuits around NZ)
Note about conservation
I believe in catch and release and not just because I don't eat animals but also for selfish conservation reasons: I want there to be plenty of fish around so that I can completely waste my life trying to catch them. And besides, I am not particularly fond of eating fish. This said, however, if you are going to 'go bush' for several weeks you may want to eat fish. Eat the old skinny ones please.
Fortunately many remote rivers experience little angling pressure and so killing the odd fish hopefully will have little or no impact. However I would recommend never killing a trophy fish (unless it's a life and death situation - which it is of course) and returning all exceptionally well conditioned fish. In other words please return the good genes.