Take a black marker and write the cooking directions on the plastic bag so you don't have to take the directions with you. Even pre-packaged dried foods can be put in plastic bags to conserve room. Not only will you save weight you carry in but also reduce the amount of trash you have to carry out. However leaving your rain pants behind when the forecast is sunny and leaving the snakebite kit at home when you're hiking in the North Cascades of Washington are subtle ways of cutting ounces. A stump will make an adequate chair, you can make instant coffee in a cup, you don't need a radio, you're just going to have to carry out those beer bottles, and you're not suppose to burn anything you can't break with your hands anyway.
People tend to fill up their backpacks even if it is too large for the planned trip.
If you are going on a weekend trip you will probably want to leave the 5,000 cubic inch pack at home. If you are very active in the outdoors you may need a couple of packs to meet your various needs depending on the activity you plan. If you spend some time going through your gear you can find a number of ways to strip off the pounds you are carrying. You might have to invest some money updating some pieces of gear, but the investment on saving wear and tear on your body is priceless, and it will bring you more enjoyment when you're in the great outdoors.