The 5-in-1 was developed in 1942 by the Subsistence Research Laboratory (SRL) of the U.S. Army Quartermaster Corps to fulfill a need for a pre-packaged field ration for use by small motorized combat groups.
Another objective was to furnish sufficient food to take care of five men for one day.
The U.S. Quartermaster Corps' Subsistence Branch originally planned for the rations to be used by troops without immediate kitchen facilities, such as trains without kitchen cars, motorized infantry, armored vehicle crews, or gun crews.
In that same year, the 10-in-1 ration was developed to replace it, as it offered a wider menu and greater flexibility in small unit issue.
[2] Though procurement of the 5-in-1 had ended with the war, the specification remained in effect and later became the basis for a postwar revision in 1948, under which the 5-in-1 nomenclature was reestablished.