The lightweight backpacking load range can vary depending on each individual person as well. As a general rule of thumb your fully loaded backpack should weigh no more than 20% of your body weight. There is a cool article that talks about How Much Your Backpack Should Weigh on our REI Co-Op Journal. It’s also good to take into consideration how much weight your pack can hold. That being said I consider myself a lightweight backpacker. My 20% weight limit is 36lbs I usually carry 23-28lbs (depending on the length of my trip).
Wow, that lightweight pack depends on how long. Overnight? Week? I've carried 80 lbs for a week in canyonlands, mainly h2o, as all the pools and springs were dry. Of course i was alot younger then. My day pack now weighs about 15 lbs, refined for those unsuspecting happenings. I feel it is best to take too much than to be without, others won't agree I'm sure. Above all have fun.
Hi Digger, the weights above refer to the gear you are carrying but not food/water. I can pretty much take the same stuff (well, that's also weather and location dependent) whether it's a two day or 8 day trip, just the food and water varies. -Alane