I have some adjustable bungees that I purchased back in 1984 for my then new Grand Touring rig. I just replace the bungee cord now and then. I can strap tightly or loosely since both ends of each cord will adjust. For bread or chips, I "bunge" the shopping bag handles so the only pressure is against nothing but plastic and rack. The soft payload does not go anywhere since it is in the plastic bag and is not crushed as no force is used against the soft payload.