History In 1941, Dr. Ancel Keys (a University of Minnesota physiologist) was assigned by the U.S. War Department to design a non-perishable, ready-to-eat meal that could fit in a soldier's pocket. Keys went to a local supermarket to choose foods that would be inexpensive, but still be enough to provide energy. He purchased hard biscuits, dry sausages, hard candy, and chocolate bars. He then tested his 28-ounce, 3,200 calorie (871 gram, 13,400 kJ) meals on six soldiers in a nearby army base. The meals only gained "palatable" and "better than nothing" ratings from the soldiers, but were successful in relieving hunger and providing sufficient energy. The Army added a few extra items and named the packs K-rations, possibly in honor of Dr. Keys. Developed using ideas from the USAAF's bailout ration, the K-ration first saw use in 1942, when it was issued to U.S. Airborne troops for testing. Initial reports praised it for the variety of the foods incorporated, as well as the light weight. Also mentioned by some was the danger of over reliance, which could cause the three meals to become monotonous if issued for long periods of time. Due to its use by Airborne troops, however, the K-ration was thereafter viewed as being a successful, lightweight, and easily-issued source of food for front line troops. All meals contained two packages of dried biscuits, cigarettes, gum, sugar (granulated, cubed, or compressed), and a key (dubbed a P-38) to open a small canned portion. Items specific to the Breakfast meal were canned meat and eggs, a fruit bar, and instant coffee. Dinner (lunch) items consisted of canned cheese and a lemon (early), orange, or grape (late) drink packet. The Supper package contained toilet paper, a bouillon packet, and a lemon, orange, or grape drink packet. Late production meals had a disposable wooden spoon. In total, the three meals provided about 3,000 calories. The K-ration was produced by the Cracker Jack company with the waxed paper ration box about the same size as the Cracker Jack box. The U.S. Army M-1943 herringbone twill (HBT) fatigue uniform had simplifed but large pockets that were designed to be able to hold a K-Ration box. The C-ration was the only ration comparable to the K-ration in widespread issue, with six cans comprising one full ration. Introduced during the late 1930s, it was heavier, with less variety in meals, but more calories. While fighting in the European Theater of Operations, the US Army discovered that troops quickly got tired of the K-ration, some being forced to eat it for months on end. As it was based on an emergency ration, the K-ration provided roughly 800–1,200 calories fewer than required by highly active men. Often, a secondary food source was issued, such as a D-ration, or fresh oranges, in an attempt to bring up the calorie count. By war's end, millions of K-rations had been produced, but the army had lost the use for them. While the ration would continue to be re-issued through fighting in Korea (and later), it was not produced much later than 1945.