Most National Parks require bear canisters for backcountry camping. Back in the old days we hung our food in bags from a tree branch in hopes that this would prevent bears from either climbing out on the branch and dropping our food, or swiping the very thin bear bag rope with one sharp claw and...success! a delicious bear meal of dried couscous and GORP. Bear bagging was no fun. I think we properly hung the bag maybe 10% of the time. Bear canisters are much more convenient (so far) except that they add extra pounds and limit the amount and size of food that you can bring.
For this trip, fitting all of our food with room for sunscreen and toothpaste into the bear canister was proving futile so I started reading up on how others do it. Apparently others are able to pack five to ten backpacking days of food for one person into a bear canister. A three day, four person trip should work. Right?! I arranged, re-arranged, smooshed, stuffed, crunched and eventually removed food. But finally the bear canister = packed. Whether or not we would have enough food plus room for other smelly odds and ends = ???
With several family backpacking trips under our belts, we have a pretty good method for packing and still keeping the kids backpacks at less than ten pounds. The availability of water at the campsite really helps to minimize weight but we still brought two tents, four sleeping bags, the bear canister with food for three days, groundpads, a stove, fuel, filter, eating utensils, warm clothes, camera and two stuffed animals. Surprisingly all of this fit into our packs and they weren't too heavy or unwieldly. Well...I take that back, packs weren't too heavy until we added a six cans of delicious Sun-Drenched IPA. Priorities!