There is no evidence that Napoleon Bonaparte, whose Grand Army conquered much of Europe in the early 19th century, ever said or wrote the words now widely attributed to him: “An army marches on its stomach.” But in the winter of 1812, during his disastrous invasion of their country, the Russians destroyed much of the food, provisions, and shelter the Grand Army might have used to survive, administering to Napoleon a brutal lesson about the importance of feeding an army. About 1 of every 6 French soldiers survived the campaign.

American military history has likewise been fraught with the problem of how to keep warfighters fed and healthy for combat. World War II was the first major conflict in which more military personnel were killed in combat than died of diseases – diseases often worsened, if not caused, by poor nutrition.

Nutrition, unfortunately, wasn’t the main criterion for the earliest field rations; foods were chosen because they traveled well. The first standard ration issued to soldiers in the Continental Army included a pound a beef, 18 ounces of flour, three pints of peas or beans, a pint of milk, a half-pint of rice and, to prevent scurvy, a quart of cider or spruce beer. This first ration immediately ran into problems: It proved impossible, for example, to supply and transport milk in such quantities, and meats had to be heavily salted to avoid spoilage.

While the Army and the Navy worked to mature the bureaucracy and infrastructure necessary to administer field feeding, the ration itself had changed very little by the Civil War, when the Union Army’s marching ration consisted of a pound of hard bread, salt pork or fresh meat, sugar, coffee and salt – hardly sufficient to supply nutrients to a mature human body. An Army camp manual written by Florence Nightingale emphasized meat and milk as protein sources and whole grains, fruits and vegetables for carbohydrates. Fruits and vegetables proved difficult to procure, however; scurvy was common in the winter, and soldiers often fought over berry patches in the spring. Some soldiers developed night blindness – poor vision in low light – due to a lack of vitamin A.

The “travel ration” distributed to soldiers in the 1898 Spanish-American War was the first military ration to contain canned meat, though it was of such poor quality that troops ate very little of it, and the hot and humid climates of the Caribbean and Pacific often caused other foods to rot. With the turn of the 20th century came the realization that field rations had to be tailored to particular combat situations and environments. New processing technologies were developed, and by World War I, the Army had devised a reliable system of bringing perishable foods to troops. Garrison rations contained more carefully calibrated measures of protein, fat, and carbohydrate – but the “reserve ration” issued to World War I soldiers still differed little from that issued in the Civil War.

As nutrition scientists began identifying the importance of particular vitamins and minerals during the 1920s and 1930s, a series of new rations were developed by the Army, beginning with the “D-ration” – basically a vitamin-fortified chocolate bar meant to stand in for a missed meal. These new rations would be the key to feeding an armed force that was deployed to every corner of the globe, and served in a variety of operational situations, during World War II. The A-ration, the classic garrison ration, typically consisted of fresh or frozen meat, fresh dairy products, and fresh fruits and vegetables. For obvious reasons, the A-ration was normally supplied to an established military base or camp, and was sometimes brought closer to the front lines with the use of portable kitchens or insulated containers. A second garrison ration, the B-ration, was composed of canned, dried and dehydrated items that could be unitized and scaled to feed people in increments of five, 10, and 100.

The most notorious of the World War II rations was the C-ration, the boxed operational ration issued to soldiers each day and initially consisting of three different canned meat entrees and two different combinations of bread, coffee and sweets (the “M” and “B” unit cans). Unfortunately, troops were forced to rely on the C-ration – designed for temporary feeding during combat or when A- or B-rations were unavailable – more than anticipated, often eating C-rations for up to 90 days. For this and other reasons, it became widely reviled.

The C-ration had other problems: Even among the 11 different varieties, there was little variation in taste and texture. The C-ration was bulky and heavy, and deployed soldiers often lightened their loads by simply discarding items. According to Sanders Marble, senior historian at the Army’s Office of Medical History, this was one reason designers of field rations tried to spread key nutrients among different food items; another was that most of the ration’s vitamin C was supplied by a difficult-to-stomach powdered lemon juice concentrate: “Troops considered it ‘bug juice,’” he wrote, “and used it to bleach floors rather than drink.”

Several customized rations emerged to feed troops in specific situations or environments during World War II. The K-ration, nutritionally dense and lightweight, was issued to airborne troops and other short-duration mobile forces. The Mountain (M) ration was designed for preparation at high altitudes; the Jungle (J) ration, which included water purification tablets, for troops in warm, wet tropical locations. Neither the M and J rations ever caught on with the Army’s Quartermaster Command; both were discontinued in 1943 in favor of the
K-ration.

By 1944, Army nutritionists, now organized into a Medical Nutrition Laboratory, were able to improve the palatability of C-rations somewhat and expand the entrée choices to 10, but ration development stalled after the war; the C-ration remained the standard in Korea, and was even used in Vietnam, where a freeze-dried field ration, the Long Range Patrol (LRP) ration, was developed for use by Special Operations troops on long-range reconnaissance teams.

In the late 1950’s, Army researchers developed what was essentially a more varied C-ration. Initially known as the Meal, Combat, Individual (MCI) ration, it consisted, like the C-ration, of individually canned items eaten at the same time. It was this concept of increased variety and portability, along with advances in food processing and packaging technology, which eventually led to the development of the Meals, Ready-to-Eat (MREs).

The MRE’s up-front design specifications were unprecedented in military feeding: It was required to be acceptable as a service member’s sole diet for seven consecutive days. New processing and packaging technologies, such as freeze-drying and flexible retort pouches, allowed for a greater variety in the MRE menu. Later improvements, such as the addition of a flameless heater and condiments such as hot sauce in the 1990’s, made the meals more palatable.

The MRE, lighter in weight and more acceptable to troops, was rolled out in the early 1980s along with a program of periodic feedback and improvement that continues to this day. Stephen Moody, who directs the Combat Feeding Directorate at the Army’s Combat Capabilities Development Command (CCDC) Soldier Center in Natick, Massachusetts, was around for the MREs’ early days, when he was an active-duty Army warrant officer during Operation Desert Storm. “We sent a lot of people over there quickly,” he said, “and they were eating MREs for a long time.” While there were 12 different menus at the time, Moody said, there wasn’t a reliable rotation system in place. “You could be eating the same thing three, four times a week,” he said. “That was a big problem, because eventually people just stopped eating.”

Under-consumption during training and field operations was a significant enough problem that the Combat Feeding Directorate (CFD) and nutrition scientists at the U.S. Army Research Institute of Environmental Medicine (USARIEM) began a review to examine it – to determine whether, and to what extent, the energy deficits caused by under-consumption affected the performance of military personnel – and to formulate strategies for reducing it.

One of the most obvious strategies, Moody said, was simply to increase the variety of MRE offerings: “So we expanded the menus to 24, and added two vegetarian menus, just to try to improve consumption. We’ve got Asian flavors, Latin flavors, and Caribbean flavors. It just reflects the diversity of the Army these days, and the tastes of the young soldiers.”

21st Century Combat Feeding

Since 1993, more than 280 new MRE items have been added to the mix, and meals are continuously evaluated and revised. While several military agencies and advisory entities work today on studying and supplying military nutrition, the key collaborators remain the CFD and USARIEM’s Military Nutrition Division (MND), also located in Natick.

The MND’s job, according to James McClung, Ph.D., the nutrition biologist who leads it, is “to understand the biomedical basis for nutrition requirements. We go where warfighters are, whether it is basic combat training, whether it is in a submarine or at the top of a mountain, to characterize nutrition requirements.” The MND’s research directly informs the CFD’s development and evaluation of food products.

This collaboration has yielded noteworthy innovations. In 2001, in order to standardize supply and packaging and reduce costs, the old LRP ration was merged with the Meal, Cold-Weather (MCW) ration – both of them compact, calorie-dense meals intended for use by active warfighters in the field. Each of the 12 MCW/LRP meals weighs about a pound and differ only in the accessory packs that accompany the entrees: MCW accessories are freeze proof and intended for use in cold weather or high altitudes; LRP accessories are for light infantry or special operations forces in temperate or hot climates.

Under-consumption and the accompanying risk of weight loss continued to be a problem for expeditionary warfighters during the War on Terrorism, particularly in Afghanistan. Lack of variety wasn’t the problem this time. It was the weight of MREs. On extended expeditions outside a forward operating base, lugging three MREs for each day of travel became far too burdensome; weight and space limitations led most service members to “field-strip,” sometimes discarding more than half their food, along with a considerable percentage of the nutrients necessary for replenishing their bodies’ fuel supply.

With the help of the National Academy of Sciences’ Institute of Medicine and nutrition experts from all over the world, MND and CFD developed the First Strike Ration (FSR) for troops serving for extended periods outside a forward operating base. The FSR, rolled out in 2009, is designed for the extreme portability demanded by a 72-hour dismounted mission, packing the nutrients of three MREs into a single container that weighs less than half as much. According to Moody, the ration is also designed for flexibility. “We have entrée-type items,” he said, “and then we’ve also added those kinds of ‘pogey bait’ items, the trail mix, the beef jerky, those type of eat-on-the-move items. There are times when you’re out there, if you’ve got the luxury of time, you’ll sit down and eat almost the whole thing if you’ve been burning a lot of calories. But there are other times when you just don’t have that time to do that.”

At around the same time as the FSR rollout, MND and CFD began collaborating on a line of calorie supplements designed to refuel service members operating under demanding conditions or environments. Three MREs a day provide service members with a minimum of 3,600 calories – but during exceptionally heavy activity, a warfighter’s daily calories needs can climb as high as 4,500 to 6,000. After a study of not only how service members burn calories while operating in different terrain, but also of their food preferences in different circumstances, Army food scientists and engineers developed the Modular Operational Ration Enhancement (MORE), designed to boost cognitive and physical performance and to counter weight loss and fatigue.

The MORE, intended as a supplement to the entrees in standard MREs, FSRs, or MCW/LRPs, is tailored to the environment in which a warfighter is operating: all contain carbohydrates, caffeine, electrolytes, and vitamins, but some contain more carbohydrate, to counter both the increased energy requirements of high-altitude operations and the symptoms of altitude sickness, while others, designed for hot weather operations, contain beverages for replacing electrolytes lost to perspiration. Each MORE weighs less than three-quarters of a pound and is easily compressible, taking up very little space.

As all these new products were being studied by the MND and rolled out by CFD, it remained the case that military customers who wanted to obtain precise nutritional information about them – calorie counts or amounts of fat, protein, carbohydrate, sugar, sodium, vitamins, and more– needed to either read the labels on products already ordered, or to contact the appropriate experts at CFD. To make this detailed information readily available to service members, military dieticians, food services officers, and other customers, the CFD partnered with the Human Performance Resource Center (HPRC) at the Uniformed Services University of the Health Sciences to create an online web portal.

It was a difficult and time-consuming process, involving chemical analysis by MND scientists of every single food component packaged into military meals, but the interactive website, the Combat Rations Database (ComRaD), launched in 2015, now offers accurate, up-to-date nutritional information about individual combat-ration menus and the individual components packed inside them.

Another recent innovation, the Performance Readiness Bar, was released just last year in response to research suggesting basic trainees are twice as vulnerable to bone injury as their civilian counterparts. According to McClung, the incidence of stress fractures during basic training – the eight- to 10-week course introducing enlisted personnel to the rigors of military service – is historically high: Up to five percent of male trainees suffer stress fractures during basic training, and up to 18 to 20 percent of women. “Through our biomedical research,” said McClung, “we’ve discovered that the requirement for calcium and vitamin D may be higher at that time, that there may be an association between vitamin D status, calcium status and the incidence of stress fracture, and that providing a product such as the Performance Readiness Bar as a snack during that period of time may optimize bone health.” The bar was developed by the CDF under the guidance of the MND.

The significantly higher rate of stress fractures among women trainees, along with other data about active-duty women in the military, has caught the attention of military nutritionists. For the most part, McClung said, the nutritional requirements of men and women are the same – with a few noteworthy exceptions. “Iron requirements for women are significantly higher than they are for men,” he said. “In fact, they’re more than double. So, this does result in some difficulty, beginning in the basic combat training environment, where we need to think about ways to provide more iron, or prevent decrements in iron state if they occur due to training.” As they begin basic training, women Army recruits are given a briefing by medical personnel on the importance of iron nutrition, and then throughout training are offered voluntary dietary supplements – multivitamins – containing additional iron.

The role of calcium and vitamin D in bone health is well known, which is why the Performance Readiness Bar offers these nutrients in abundance – but the degree to which iron depletion plays a role in the higher rates of stress fractures among women trainees isn’t yet known. “It’s likely that there is some association between poor iron status in the incidence of injury,” McClung said, “and that’s also an active area of nutritional science research.”

Feeding for Lethality

McClung and Moody both realize the military has encountered problems in field feeding during every conflict in its history, and that these problems were identified and remediated ad hoc – often too late to be effective, and ensuring that the armed forces began each new war with operational rations designed to avoid the problems of the previous war. One of the most recent developments in field feeding, still under way, is an attempt to create a solution as the need arises for it within the armed forces.

When Gen. Mark A. Milley became the Army’s chief of staff in 2015, he developed strategic guidance that built on the Army modernization concept espoused by his predecessor, Gen. Raymond Odierno. The battlefield of the future is likely to look quite different, relying less on massive force mobilizations and more on “light footprint” operations carried out by smaller groups of specialized forces. “The current chief came in and we started talking about near- peer adversaries, what the battlefield of the future might look like,” said Moody. Those discussions evolved to envision small units that could operate semi-independently for seven days without resupply. “That really caught our attention, because our rations right now aren’t really suitable for that.” Such an expedition would require a service member to carry about 32 pounds of MREs, or 18 pounds of First Strike Rations.

In March 2018, then-Secretary of Defense James Mattis acted on his concern that a growing number of training and duty requirements for close-combat infantry warfighters – many of which had little to do with making them deadly – were sapping the ability of U.S. infantry to engage in their core mission of intense, violent close-in fighting. To remove these obstacles and provide infantry units with new training, tools and technology to provide overmatch, Mattis established the joint-service Close Combat Lethality Task Force (CCLTF).

The CCLTF is working along several lines of effort – including human performance, which McClung said necessarily involves nutrition. “A number of efforts in the modernization of the Army and the DOD [Department of Defense] are focused on lethality, particularly close-combat lethality,” he said. “Human performance is, of course, one dimension of that, so efforts we share with the Combat Feeding Directorate are really aimed at tailoring the feeding platform to the environment – in this case, tailoring it to close combat.”

While the CCLTF goes about its work, the MND and CFD are working to develop the next generation of operational rations, known as the Close Combat Assault Ration (CCAR), which is envisioned to achieve about a 40 percent reduction in both the weight and volume of the First Strike Ration while further boosting physical and cognitive performance. “We’ve looked to see what we could do to make the ration even smaller and lighter,” said Moody.

A pair of new technologies is helping with this effort: first, vacuum microwave drying, which helps create compact, lightweight and nutrient-dense food. Among other foods, Moody said, the CDF is testing VMD on cheesecake. “It sounds a little exorbitant for a ration,” he said, “but it’s a good test for us. It’s very dense in terms of calories and energy. We’re able to vacuum microwave dry this cheesecake to a point where we’ve pulled off enough moisture to make it shelf stable, but it still has a soft enough mouthfeel that you can just eat it as is.”

Mouth feel is an important factor in the CFD’s evaluations; reducing a ration’s footprint to an absolute minimum will be of little value if it renders food dry and unpalatable. A new compression technology, sonic compression, can help improve the texture of dried ration foods. Instead of just drying and squishing food, Moody said, the new technology applies sonic waves during compression that fuse food molecules together. “So, instead of a crumbly product,” Moody said, “you have more of a solid food bar.” Some tricks of the industrial trade used to smooth out compact energy bars – adding syrups and binders, for example – tend to add non-nutritional bulk, as well as unhealthy sugars. “We definitely don’t want to go that route,” Moody said. “So, by adding sonic energy, we can avoid adding some of those ingredients, while still allowing warfighters to eat food out of their hands without it crumbling all over the place.”

With these new technologies, CFD engineers are evaluating several new candidates for inclusion in the CCAR, including a compressed chili con carne bar that can either be eaten dry or rehydrated into a stew if time permits – but Moody knows stew-building is a luxury most warfighters on dismounted missions won’t be able to afford. The CCAR’s reduced footprint will necessarily involve less flexibility. “Our intention, really, for the CCAR is that it’s not a sit-down-and-eat -type ration,” he said. “It’s a snack on the move. You’re not going to have time to eat. It’s just to give you energy until you can get back to a base.”

Even as operational rations are shrunk to their absolute minimum, the Army’s nutrition scientists are still looking to the future, when the focus of research and development efforts may turn from the foods service members eat to the way in which their own bodies absorb and process nutrients. The body’s inflammatory response, for example – which is particularly relevant to close-combat situations – is known to affect the absorption of nutrients. “We’re trying to study ways to overcome that inflammation,” said McClung, “whether it’s through providing the right nutrients at the right time or combating the effects of inflammation in a different way, perhaps in a medical way.”

Another area of potential innovation is research in the human microbiome – the ecosystem of microorganisms in the human body, particularly the gut. “We’re working to understand the effects of consuming the ration on the microbiome, and the effects of the environment on the microbiome,” McClung said. “Perhaps we can harness the microbiome itself to overcome nutritional demands.”

It may seem like science fiction – a wild idea, manipulating the human ecosystem to reduce the amount of food a soldier has to carry – but at the pace the Military Nutrition Division and the Combat Feeding Directorate have been working over the past decade, it’s a future that seems far more likely than not.

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