The Quartermaster Corps, one of the seven technical services, was in charge of developing field rations for the U.S. Army during World War II. Until February 28, 1942, the Quartermaster Corps was an agency directly subordinate to the War Department. On July 31, 1942, the Quartermaster Corps, now under the Army Service Forces, was reorganized. As part of the same Army Service Forces order, in interest of standardization, the most major parts of all the technical services were to be called "divisions." The agencies under their control were to be called "branches," who would each control one or several "sections."

What had been the Supply Division of the Q.M.C. was broken up. The personnel associated with buying went to the new Procurement Division, while most other personnel went to the Storage and Distribution Division; those concerned with military rations went to its Subsistence Branch. Actual research into the development of the content of the rations themselves was not at a central location (i.e., Fort Lee), but a function of both the Subsistence Branch and a scientific office within the Chicago Quartermaster Depot known as the Subsistence Research Laboratory.

With the reorganization of the Quartermaster Corps in July 1942, final authority over research and development activities on all Quartermaster items were moved to the Research and Development Branch within the new Military Planning Division. A Subsistence Research Project Board, made up of high-ranking personnel from the former Supply Division, and meant to provide suggestions on all activities of Army subsistence, not just rations, was formed at the same time. In December 1942, the Subsistence Research Laboratory was removed from the authority of the Chicago Quartermaster Depot and subordinated to a new Subsistence Section under the Research and Development Branch. In 1944, the director of the Laboratory was also tabbed to simultaneously head the Subsistence Section. Development of packaging for rations was vested in the Storage and Distribution Division. In May 1944, the Subsistence Branch became a full-fledged Division within the Quartermaster Corps.

"Finished" ration components (such as sealed packages of biscuits, wrapped caramels, or packs of cigarettes) were acquired and assembled into complete rations by civilian companies, known as prime contractors, that had signed contracts (usually stipulating a set number of complete rations within a certain period of time) with the Quartermaster Corps. The prime contractors set up production lines and obtained completed food or non-food items from subcontractors. Subcontractors were provided with specifications or recipes for ration components from the Quartermaster Corps, with a bit of variety between each. When the specifications of an item or a recipe was changed, it took approximately three months to show up at the front lines. Some leeway was allowed for prime contractors so that bottlenecks would not form in production; cigarettes could be Camels, Chesterfields, Lucky Strikes, or others, and up to five types of biscuits using differing ingredients were in production in the summer of 1943.

Changes within rations were decided upon both by the scientists and nutritionists at the Subsistence Research Laboratory and soldiers in the field, either during testing periods or reports from combat. When the K ration was first proposed by the Chief of Infantry in 1941, one of the requirements was that the package be no bigger than 6 inches wide, 2 1/2 inches long, and 3/4 of an inch thick, in addition to weighing less than 3/4 of a pound, so that it could be easily carried in the chest pocket of the paratrooper's uniform shirt. Exercises in places such as the Louisiana Maneuver Area in 1940, 1941, and 1942 provided valuable feedback before the main field rations used by the Army during WWII (the C, D, and K) got their combat test. It was noted that comments from soldiers were overly general, and it was often difficult for Quartermaster Corps observers to work out what exactly was being complained about, especially on the front lines.

I talk a little bit about the evolution of various U.S. Army rations during the war years here, and also link to an excellent site that has information about the development of the K ration and decisions behind those changes. You will note that several items were added or dropped to satisfy those in the field, provide additional nutrition at a lesser weight, or a greater variety. Taste was often sacrificed to meet specifications such as overall level of nutrition, size, or weight. Soldiers didn't particularly like the K ration hash, and feedback led to the replacement of the ascorbic acid-heavy lemon drink powder, which was universally detested as "battery acid."

We used K ration lemon powder dissolved in buckets of water for scrubbing the floor when we were living in buildings, and it worked out exceptionally well, cutting dirt spots and more or less bleaching the wooden floors.

The German field ration was apparently quite decent, but a step below what the Americans could offer. Late in the war, they attempted to develop something similar to the K ration.

Source:

Risch, Erna. U.S. Army in World War II, The Technical Services, The Quartermaster Corps: Organization, Supply, and Services, Volume I. Washington: United States Army Center of Military History, 1995.