A light weight flat container such as a bottle (20) formed of an elastically deformable plastic material and having a staged load bearing system including primary and secondary load bearing surfaces. The bottle includes two op posing wide sides (21, 22) and two opposing narrow sides (25, 26) on which the load bearing surfaces may be disposed. A base (27) is provided which protrudes beyond the narrow sides (25, 26) in some embodiments. During processing of the bottles on a conveyor fill line, mating primary load bearing surfaces (30, 30′) on adjacent bottles initially engage and begin to deform under contact forces. The mating secondary load bearing surfaces (32, 32′) next engage to better distribute the contact forces and control deformation of the bottles to below the elastic limit of the plastic material to avoid plastic deformation or crazing damage to the bottles when the contact forces subsides. A bottle processing method is also provided.