Food,
Mostly I use a Thermarest Prolite 3, Short, sleeping pad rolled without folding lengthwise protected by a silnylon stow sack. It makes a cylinder about 24" long and I put it under the compression straps of my pack. The cut off pop bottle fits neatly and snugly over the top of the pad. Handy for a quick water stop and it also armor plates the top 7" of the pad.

For those trips when I don't use the Prolite, I just put my cook pot and its contents inside the "bucket" and stow the thing inside my pack. I just got a Six Moons Starlite that uses my sleeping pad as part of the pack. I'll be carrying the little pop bottle bucket inside from now on I guess.