This is very important. Sit down and plan the meals ahead of time and buy accordingly. I recommend the NOLS cookbook for some good, lightweight easy to make meals. Next we move on to what I call the tool shed. Now this is where I diverge from the normal school of backpacking.
Most people think packing is all about harmonizing with nature and being one with the forest.
I am a wildlife biologist, I know nature is not some cute fluffy Bambi movie. Oh yes, you can be one with nature, usually as the midnight snack for some bear. People tend to forget that they are no longer at the top of the food chain when in a true wilderness area. I have been chased by bears in New Mexico and stalked by a jaguar in old Mexico, really exciting but not the type of oneness most people think of. I intend to survive my nature hikes.