Photograph of K ration

U.S. Army Quartermaster Foundation

Rations are the food supplied to soldiers, sailors, and airmen. Along with ammunition, they make up the most vital supplies without which an army cannot long remain operational. The ideal rations are inexpensive, easy to transport, imperishable, lightweight, nourishing, and tasty. No army of the Pacific War came close to simultaneously meeting all these requirements, and many a veteran can testify that taste was the first quality sacrificed in making the inevitable trade-offs.

Nutritional requirements for a man of military age (18 to 30 years old) could be broadly divided into an energy requirement (quantity of food) and essential nutrient requirements (quality of food.) The minimum energy requirement for men not engaged in physical activity was about 2400 calories per day, equivalent to 600 grams (21 ounces) of dry carbohydrate or protein or 270 grams (9.5 ounces) of fat. With the added physical activity of military service, the requirement soared, to as much as 4000 calories per day. If this energy requirement was not met by rations, the men would begin to lose weight, first as body fat (assuming they were physically active) and then as muscle and organ mass. In the intense but episodic combat that characterized the Pacific, it was not uncommon for men to lose considerable weight during a campaign, then regain weight after returning to a base camp. So long as the weight lost and regained was primarily body fat, this cyclic weight loss and gain was fairly harmless, but if weight loss reached the point where muscle and organ mass was lost, there was potential for permanent damage. Prisoners of war and others who survived prolonged starvation had a significantly reduced postwar life expectancy.

In addition to supplying calories, rations had to to supply essential nutrients to maintain long-term health. These included essential amino acids (from protein) and fatty acids, minerals, and vitamins. The most common deficiency diseases among inadequately fed troops were scurvy (due to lack of vitamin C), beriberi (due to lack of thiamine), pellagra (due to lack of niacin), and night blindness (due to lack of vitamin A). Beriberi and pellagra could be prevented by supplying troops with whole grains or fortified white flour or pasta, but the traditional Japanese diet of polished rice was so deficient in thiamine that Japanese soldiers sometimes developed beriberi even in garrison. The Army was aware that this could be prevented by mixing rice with barley, but the mixture was disliked by the soldiers and was considered too difficult to transport. Vitamin A could be supplied with canned or dried vegetables. Vitamin C, supplied by fresh fruits and vegetables, was a particularly challenge, as it is chemically somewhat unstable and is destroyed by many preservation processes. The Western Allies often supplied Vitamin C as part of a powdered beverage mixture, while the Japanese Army gave its soldiers a pay allowance for purchase of fresh vegetables while in garrison and apparently relied on foraging while on campaign.

While lack of fat poses little danger of deficiency disease, fat is a dense source of calories, which is important for men engaged in heavy physical activity. A diet lacking in fat is also a diet that lacks flavor and leaves the eater feeling hungry even if the calorie intake is sufficient. Western rations provided fat as meat or cheese; Japanese rations provided relatively little fat, mostly in soybean paste (miso), but the Japanese palate was accustomed to a lower percentage of fat in the diet.

Because a man could function for a significant length of time without some essential nutrients and on insufficient calories, there was a tendency for all the armies of the Pacific War to supply troops in combat with rations chosen more for their ease of transport and imperishability than their nutritional value. It was assumed that the missing nutrients and calories would be made up later, when the troops were pulled off the line and could be given regular rations supplying all the nutritional requirements.

United States. U.S. Army planners assumed that troops overseas would require 6.22 pounds (2.82 kg) of rations per day. The ration allowance for an American infantryman in the Pacific was very generous at 4758 calories per day. However, it was not always possible to get the regulation ration in sufficient quantities through stretched supply lines to forward areas, as proved to be the case with the Marines on Guadalcanal.

The Army devised a number of standard rations based on different trade-offs for different situations. Troops fortunate enough to be close to modern facilities for transportation and refrigerated storage were given the A ration, which included fresh, frozen and refrigerated ingredients and supplied ample calories and nutrients. The B ration replaced the fresh, frozen, and refrigerated ingredients with canned or preserved ingredients and was available where field kitchens could be set up but refrigeration facilities were lacking. It also supplied ample calories and nutrients, the chief complaint being that it was rather monotonous. The 10-in-1 ration, introduced later in the war, was a prepackaged version of the B ration providing a day's ration for ten men. A B ration included three varieties of meat, four vegetables, a dessert and canned fruit or fruit juice.

The C ration was for use under combat conditions where field kitchens were unavailable. It was a precooked ration consisting mostly of breads and meats. A day's ration consisted of three cans each of bread and meat dishes and an accessory pack. An attempt was made to introduce variety into the ration: The bread component could be biscuits, prepared cereal, candy, or other carbohydrate sources together with instant coffee and a beverage powder that supplied Vitamin C. The meat component could be meat and vegetable stew, meat and spaghetti, pork and beans, or other meat combinations providing protein and fat. Because of the requirement for mass production, most of the meat component early in the war was meat and vegetable hash, which proved highly unpopular. The beverage powder was so acidic (to help preserve its vitamin content) that it was discarded by many men. The accessory pack included sundries such as cigarettes and matches, toilet paper, water purification tablets, and chewing gum. The C ration provided 3700 calories per day, barely adequate for  young men engaged in strenuous physical activity, and it was not intended to be used for more than 21 days.

The original C rations were bulky and heavy, and lighter, more compact rations were devised based on the lessons of Operation TORCH in North Africa. "Canned heat" was added to the ration after it was discovered that the ration was tasteless when eaten cold; this was a wick leading to a heating element inside the ration can which heated it within seconds. The rations cans were painted green after suspicions were raised that the glint of discarded cans was giving away American positions to enemy reconnaissance.

The K ration was a lightweight combat ration that emphasized compactness and imperishability. It supplied only 2700 calories and was not intended to be used for more than 15 consecutive meals, but in practice it was used interchangeably with C rations. It came in breakfast, lunch, and supper versions composed of biscuits, cereal or fruit bar, candy, processed meat or cheese, and other highly processed foods.

The D ration or "Logan Bar" was an emergency ration consisting of a chocolate and oat flour mixture supplying 600 calories per bar. Designed to withstand temperatures of up to 120 F (49 C), it was so hard that it sometimes had to be eaten by slicing off flakes with a knife. It was also rather bitter and proved unpopular. The Army apparently considered this a feature, not a bug, ensuring that troops did not eat their D rations until they were actually needed. Over 170 million D rations were manufactured during the war, producing such a backlog that the ration began to be used outside of emergency situations, and serious consideration was given to re-manufacturing surplus D rations into a confection for emergency feeding of civilians in occupied areas.

A veteran of the Americal Division summarized the G.I.'s outlook (Bergerud 1996):

We had Spam every day for six months. Then the next six months we had Vienna sausage. Then we received what they called "D rations." It was a kind of chocolate brick that you couldn't break with a brick. Nobody had ever heard of this stuff before. And pancakes like you wouldn't believe, every damn day. Flour and water with syrup made of sugar and water. There was some kind of grease involved. Someone got his hands on a mountain of lousy Australian jam that was always around. Out in the field you had canned rations, usually some kind of stew from World War I, or before for all I know. Field soldiers also got hardtack, a kind of dried cracker that had the texture of wood. You would soak it in coffee and it would blow up like a balloon. For those special occasions we got dehydrated mashed potatoes that had the consistency of mud. No breakfast was complete without wretched dehydrated eggs. Later we started getting some Australian "bully beef." For my money that was the worst. You'd open up those big cans and inside was congealed fat with bits of ancient steer mixed in. Incredible. Rumor had it, the Australians actually liked the stuff. We did have canned fruit that tasted like food. I honestly think the guys spent more time talking and dreaming about good food than they did about good-looking girls. The Army sure took care of you.

Soldiers of other armies would likely wonder what the Americans were complaining about. The food was usually plentiful and nourishing even if it was monotonous and not always appealing. U.S. nutritionists erred on the side of caution, set the minimum requirements for various nutrients at about 30% above the average requirements, so that the American soldier's diet was arguably rather overgenerous. Nevertheless, given that the regulation ration didn't always make it to front line troops at the end of long supply chains, there were concerns that borderline malnutrition was contributing to combat fatigue.

American ration scales caused considerable friction in China, where the demands of American forces were sometimes fiercely resented by local Chinese commanders and administrators. Most of China was barely existing at the subsistance level, and some provinces, such as Honan, were experiencing actual famine and mass starvation at a time when the Americans were expecting their usual beef rations, which could only be supplied by butchering oxen needed for agriculture.

Towards the end of the war, an assault ration was developed for troops making amphibious landings. This consisted of cigarettes and candy, which experience showed were the only rations of much interest to troops entering intense combat. This ration was initially a field improvisation using commercial candy obtained in Hawaii, but a standardized assault ration was authorized just as the war was winding down.

Troops making an amphibious assault were often fed a breakfast of steak and eggs prior to embarking in their landing craft. This was good for morale, though the heavy breakfast may have been detrimental to combat efficiency and made abdominal wounds more dangerous. Great efforts were also made to supply fresh bread, another morale booster, sometimes using improvised ovens and ingredients.

Thanksgiving menu on a CVE

U.S. Navy. Click to enlarge.

Soldiers complained, with considerable cause, that sailors and airmen enjoyed much superior rations. This was an inevitable result of the fact that the Navy and Air Force were more closely tied to rear facilities. The crew of a battleship typically consumed about 250 pounds of coffee a day, and all the larger warships featured a "gedunk bar" supplying fresh ice cream. An unofficial tradition grew up among destroyermen, who had no such amenities, of demanding ten gallons of ice cream for the return of each rescued airman to his carrier.

Commonwealth. British Army rations in the peacetime 1930s were little short of appalling, to the point where they were a major drag on morale. In 1938 a major food reform effort was initiated in the army, and by early 1941 consultants from the catering industry were brought in to improve Army food. Nutritionist Cedric Stanton Hicks described the Soyer stove used in British field kitchens as "the most efficient destructor of Vitamin C that could be devised" (quoted in Collingham 2011) and pushed for its replacement with the more effective Wiles steam cooker. However, the British field ration in 1941 was still based around bully beef and biscuits, the latter described by one Army cook as "a cross between Cream Crackers and Dog Biscuits" (ibid.)

British and Australian rations generally came to resemble American rations, but with a somewhat less generous calorie allowance and with tea in place of coffee. The basic combat ration was the Composite Ration or "compo ration", introduced in late 1942, which resembled the American 10-in-1 ration. One of its more popular components was a biscuit and marmalade ration resembling the bread unit of the American C ration, while the Commonwealth equivalent of the meat unit of the American C ration was often canned bully beef. The Australians consumed considerably quantities of canned mutton, which was also supplied as reverse Lend-Lease to American troops (who came to despise it.) However, the Australian combat rations were even more monotonous than American rations, using just 24 food items in place of the 39 different items used in American combat rations.

A somewhat unusual component of Commonwealth rations was Tasmanian field peas, which were meant to be placed in empty milk cans with a little water and allowed to sprout. This produced a food item high in vitamin C. However, seed sprouting in combat conditions was somewhat problematic, and some units in the South Pacific simply boiled the peas, which ruined them as a source of vitamin C.

The Commonwealth equivalent of the C ration was the operational ration, built around a can of meat and vegetables, a packet of biscuits, dried egg, oatmeal, tea, and chocolate fortified with vitamins B and D. This supplied about 4000 calories. The K ration equivalent, described as an emergency ration, was a fruit bar, dried meat and vegetables, and milk tablets, supplying 3900 calories. The operational ration was initially welcomed by troops in New Guinea, but they quickly tired of it, although the fortified chocolate bar remained popular.

An unusual source of B vitamins for Commonwealth troops was Marmite, a yeast extract produced as a byproduct of beer brewing, which was added to British rations during the First World War to prevent beriberi. Marmite was not a standard ration during the Second World War, but was sometimes available as an alternate ration. There were apparently significant quantities stockpiled at Singapore, and, following the British surrender, those British prisoners of war and civilian internees who suffered the worst from vitamin B deficiency were doled out small portions of Marmite (Thompson 2005):

Doctors prescribed small amounts of vitamin B-rich Marmite for the treatment of scrotal dermatitis [arising from vitamin B deficiency]. One patient showed no signs of recovery until it was explained to him that he should eat the Marmite, rather than paint it on the affected area.

The other condition caused by vitamin B1 deficiency was "happy feet", a gnawing, burning sensation in the soles of the feet which forced men to hobble up and down all night seeking relief from the discomfort. This condition was also treated with Marmite....

The Indian Army faced some particular challenges in devising suitable rations. Most of the Indian troops were either Hindus, who had a religious prohibition against eating beef, or Muslims, who had a religious prohibition against eating pork. Either two different kinds of rations had to be provided, with the potential for an explosive situation if the wrong rations were sent to the wrong regiments, or rations had to be devised that were acceptable to both groups. The American offered canned soy chunks in place of meat, but this was extremely unpopular. More successful was canned mutton, which was acceptable to both groups and was carefully and prominently labeled as halal (for Muslims) and jhatka (for Hindus and Sikhs.) This became the basis for a composite ration providing 4400 calories per day. Fresh vegetables, fruit, and marmite were also included in Indian Army rations. The operational ration, of 2700 calories, featured chocolate, cheese, biscuits, sardines, sugar, milk powder, tea and salts, while the emergency ration was a fortified chocolate bar of 1350 calories.

Japan. The peacetime Japanese Army of the 1930s fed its soldiers well. The ration in 1929 was a generous 4000 calories. Emphasis was put on Chinese and Western dishes, particularly meat and fried foods, which were high in calories and which sidestepped the problem of catering to regional preferences in Japanese dishes. The Army also became involved in improving the civilian diet through education. However, these reforms were seriously undermined by the war in China, and both the civilian and military diet became increasingly austere. In 1941 the military ration was halved.

Rice was not a completely satisfactory ration for the South Pacific. It was prone to spoilage under humid conditions and, unlike the canned meat supplied to Allied soldiers, it could not be eaten raw. The infantry were expected to cook their rice in their own mess kits, which eliminated the need for field kitchesn, although the smoke from cooking fires could give away a unit's position during daylight. However, the soldiers preferred rice to biscuits or bread.

Japanese infantrymen in the South Pacific were sometimes alloted as little as 600 grams (1.3 lbs) of food per day while in combat, which if supplied solely as uncooked rice translated into a meager 2160 calories per day. A more typical field ration was the Assaku Koryo (Compressed Ration), consisting of about a kilogram (2.2 lbs) per day of dried cooked rice, soybean paste (miso), powdered soy sauce, and salt, to be supplemented with whatever could be foraged locally. When circumstances permitted, the basic ration was supplemented with canned vegetables and seafood. American troops were fond of captured Japanese canned tuna and crab meat, which were a welcome change of pace from their usual combat rations.

When in garrison, Japanese troops typically received a larger ration, including about 28 ounces (800 grams) of rice or a rice and barley mixture meant to prevent beriberi, 7.4 ounces (210 grams) of fresh meat or fish, ample vegetables (21.2 ounces or 600 grams), and condiments. The barley and rice mixture was unpopular with the troops in spite of its nutritional merits, and so was often served already cooked to prevent the troops picking out the barley. This ration provided roughly 3000 calories per day.

The closest Japanese equivalent of the American K or D rations was the Netsuryo Shoku (High Nutrition Ration) which consisted of rice crackers and candy or peanut or sesame bars.

Japanese military policy was that the army abroad should live off the land. Given the limited availability of shipping and the need to import food to the home island themselves, the Japanese Army felt it had no other choice. Thus heavy requisitions were made of the indigenous farmers in occupied territories. Where local supplies were inadequate, food was redistributed from other parts of the empire. With control of the rice exporting areas of Thailand, Burma, and French Indochina, there should have been sufficient rice for the Japanese Army in southeast Asia. However, the rice trade was grossly mismanaged, resulting in a precipitous drop in production,and the Army was insatiable in its demands, leading to widespread starvation in some of the most agriculturally productive areas in the world.

Japanese troops who captured a store of Australian rations on the Kokoda Trail risked air attack rather than abandon their booty (Collie and Marutani 2009):

What a feast all these things were to us. It seemed as though we had suddenly landed in fairyland. We had run out of the meager rice ration long before, and had trudged on day and night eating only tasteless Army crackers which we call kammempo, with occasional wild potatoes and papayas.... Here in the Papuan mountains the standard of living was higher than in Japan! I thought I saw something of the appalling power of Anglo-American civilization that Japan had so recklessly challenged.

However, the Japanese soldiers found canned corned beef so disgusting that they threw away the rations after tasting them.

China. China had sufficient if not ample food until 1940, thanks in part to favorable weather. The weather in 1940 was much less favorable, with the rice harvest down 18% and wheat down 40%. This triggered a food panic that swept up even the central government, and refugees from Shanghai and Hong Kong brought an influx of cash that triggered a disastrous inflationary spiral that lasted beyond the end of the war. The government introduced "compulsory borrowing" of food in July 1943, which was effectively a surtax on the normal land tax. This effectively exported famine from the cities to the countryside.

The Chinese Army itself was always obligated to live off the land, and the burden imposed on the peasants of feeding the army while subject to unpaid conscription to build fortifications brought about a collapse of agriculture. This was worst in Honan, where terrible weather followed by a literal plague of locusts reduced the harvest by 25%. The province was garrisoned by 300,000 troops, and neighboring provinces refused to release their food reserves. 

The Chinese Communists were already reconciled to the necessity of devoting much of their energies to farming and weaving. The accomplishments they claimed were impressive: Grain production was claimed to be 13.5 million tons in 1944, significantly more than the Germans extracted from the Ukraine during its occupation. The Communists were initially careful not to requisition so much from the peasants that their goodwill was threatened, which may have hindered Communist resistance to the Japanese but proved decisive in the civil war that followed the Pacific War.

Water. Providing potable water was a challenge even in the rain-soaked jungles of the South Pacific, because of the danger of dysentery from contaminated water supplies. The challenge was even greater in dry areas such as the Dry Belt of Burma or the smaller atolls of the central Pacific that lacked any fresh water springs. Where local fresh water supplies were available, they could be decontaminated by boiling, filtering, or chemical disinfection. 

American troops in rear bases were given a very generous water allowance of 70 gallons per day per man. This dropped to as little as five gallons per day per man in advanced bases and to less than a gallon per man per day in combat. A mobile water purification unit was installed on a 2-1/2 ton truck chassis and pumped suspect water through a pressure sand filter after chemical treatment with chlorine and alum. The chlorine was a potent disinfectant, while the alum coagulated fine contaminants for easier removal. This unit was capable of processing 75 gallons (280 liters) per minute, easily enough to supply a division in combat. A smaller portable version could produce 12.5 gallons (47 liters) per minute. The sand filters were being replaced by diatomite filters towards the end of the war, which were more effective at removing cysts that resisted chlorination. 

Structural formula for halazone Fair use may apply.

Troops in the field were equipped with 36-gallon (136 liter) Lyster bags at the rate of 1 per 100 men. These were used primarily to transport and store water that was already purified, but in a pinch they could be used to disinfect water using calcium hypochlorite, which released chlorine when dissolved in the water.  Individual troops were also supplied with iodine or halazone tablets for chemical disinfection of water, often as part of their combat rations. Halazone, 4-[(dichloroamino)sulfonyl]-benzoic acid, was more effective than iodine, releasing chlorine when dissolved in water. The iodine or halazone was typically added to a canteen of water and allowed to do its work for at least thirty minutes. This was convenient for individual soldiers in the field who did not have ready access to regular water supplies.

Water held at a rolling boil for at least one minutes was generally rendered safe to drink, but, while straightforward, this method required a significant amount of time and fuel. The boiled water was also easily recontaminated unless it was chlorinated after cooling.

Japanese troops were sometimes supplied with calcium hypochlorite and alum for water purification, but water purification troops were assigned to large formations to provide water by filtration. An Epidemic and Water Supply Unit numbered eleven officers (including seven doctors and a pharmacist) and 250 men, who purified water using porcelain microfilters. Each unit had four automobile filters (modified from fire engines) capable of filtering 30 tons of water per hour, plus eight smaller filters on horseback capable of filtering 720 liters (190 gallons) per hour. 

Where only salt or brackish water was available, there was no practical alternative to distillation for supplying water to large numbers of troops. Distillation plants were standard equipment on oceangoing vessels, and bases on islands without a fresh water supply either had to install distillation plants or rely on anchored ships for their water supply. The U.S. Navy converted a number of small tankers to distillation ships with oversize distillation plants for use at advance bases, but, because of the high fuel cost of distillation, most of these ships ended up transporting fresh water from safe sources in rear areas.


Bergerud (1996)

Charlotte's Axis Attic (accessed 2011-7-3)

Collie and Marutani (2009)

Collingham (2011)

Drea (2009)

Dunnigan and Nofi (1998)

FM 21-10 (1945-7; accessed 2012-8-17)

"Handbook on Japanese Military Forces" (1944-9-15; accessed 2011-7-3)

Koehler (1958; accessed 2011-6-17)

Leighton and Coakley (1955)

Longino (1946; accessed 2011-6-17) (accessed 2012-8-16)

Mitter (2013)

Tamayama and Nunneley (2000)

Thompson (2005)

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