Food -- or more accurately a lack therof -- has been a weapon of war for almost as long as humans have fought wars.
In Medieval Europe, one of the most famous strategies used against fortresses and castles was the "siege." A siege surrounds the city/fortress/castle with an army and prevent anyone from getting in or out. Sieges had been used since the first days of civilization. The siege prevents food from getting into the besieged location and the resulting famine demoralizes the non-combatants and defenders start to die from starvation and diseases related to malnutrition.
By the 18th Century, the principles of the siege were expanded into what is now known as a blockade. A blockade is an effort to cut off an entire country from international trade, by military means. Since it is directed against an entire country, a blockade doesn't always affect food, but not all nations can grow enough food to feed their entire populations. The ultimate expectation is that the blockaded country will capitulate as it runs out of resources necessary to continue fighting.
Today, we more commonly use sanctions instead of sieges and blockades. Sanctions are multinational embargoes (stoppage of trade) against a specific countries. Like a blockade, it doesn't necessarily affect food supplies as some nations have abundant agriculture, but it can affect food supplies in nations with limited agricultural resources. The ultimate expectation is that the embargo will cause the targeted nation to run out of resources and capitulate.
Since war disrupts normal growing seasons, displaces or destroys agricultural communities, and disrupts transportation of foods because war destroys transportation routes, such as bridges and highways, providing or withholding food during times and in areas of war can be critically potent weapons with the same magnitude of impact as bombs and guns of the opposing military forces. As illustration, the Marshall Plan following World War II was designed to prevent the starvation and resultant social upheaval stemming from the food shortage or inaccessibility that occurred after World War I, because war impoverishes governments and citizens to the extent that governments cannot distribute food and citizens cannot procure food even should food be available to governments and citizens. More recent illustrations have occurred in Liberia, Mozambique, Somalia, and Sudan where food distribution to refuges, often sheltered in refuge camps, has been the focus of effort where imposed famine has been a key component of oppositional military strategy. Food can be withheld during war in several ways:
- preventing its cultivation, growth and harvest
- destroying harvests once collected
- preventing transportation and distribution
- contaminating foods so they are unfit and unsafe to eat
- displacing agricultural communities and replacing local farmers with the conqueror's own colonizing farmers in order to establish the conqueror's hegemony (hegemony: aggression or expansionism by large nations over smaller ones to achieve domination)
- destroying agricultural areas by "salting the earth" or by destroying irrigation systems (salting the earth: the ancient ritual of spreading salt on conquered cities and lands, though historians are still unclear, because of scant records, about what the process of sowing salt was in the ritual, e.g., symbolic or vast amounts); it is said that in the Punic Wars with Carthage, Rome defeated the armies of Hannibal then ploughed the arable land with salt to make it inarable, infertile
- fouling water supplies, like wells, with dead animals as was done as late as the American Civil War
- subjecting a city of area to the laying of a siege in which a city of area is surrounded so food supplies cannot be brought into the city or area; the people are left to starve or surrender; e.g., Homer's Iliad recounts the siege of Troy by the Achaeans (Greeks); a million Russians starved as a result of the 500-day siege of Leningrad by Hitler's forces during World War II
- sieges can backfire when the besieging forces cannot get food supplies themselves because of being surrounded by hostile enemy forces who are sympathetic with the population being held under siege
- embargoes of critical war materials including food, medicine, metals, oil, e.g., England's embargo by sea of Napoleon's occupied areas
- modern international economic santions
- modern regional conflicts targeting populations for genocidal starvation
- "scorched earth" tactics to preventing invading forces to sustain armies by living off the land in an attitude of "I'd rather burn the land than let the enemy live off it," e.g., Russians burning forests, stores of food and transports as Hitler advanced toward Moscow in World War II
"An army marches on its stomach." Napoleon stated the truth of warfare: without food, an army cannot successfully advance. When, during the Napoleonic Wars, Napoleon's army marched to Moscow, they survived Russia's scorched earth tactics, yet, upon reaching Moscow, Napoleon's troops were so starved and weak they couldn't take Moscow and had to retreat. Technologies for preserving foods have helped armies since napoleon offered a prize for a method to prevent spoilage in the foods for armies. In 1795 French chef Nicholas Appert developed the method of preserving meats, fruits, vegetables, and milk in jars, a method still used today for home canning. In 1810 England adapted Appert's methods and canned these foods in tin containers. At the Battle of Waterloo, both the French and English armies and navies survived by eating canned foods processed according to Appert's method. Additional technologies--canning, freezing, dehydrating, and irradiating food--has further advanced the independence of marching armies from the need to live off the surrounding land and made them further removed from the effect of a scorched earth strategy.
Dehydration of foods--dried figs, raisins, dried apricots, beef jerky and ostrich biltong, etc--has been a critical source of foods for armies throughout the ages and one that has helped them sustain their own supplies while laying siege to an opposing force. Frozen foods, first developed in 1920, were important for American troops in World War II and helped gave independence from living off the land. Irradiated foods were developed in the 1960s by the military and NASA together; they were tested on soldiers on military bases before being implemented as part of war rations, again increasing military independence from the land in combat areas, and as part of space travel rations (irradiated foods: foods that undergo molecular change as a result of treatment with a radioactive substance that is generated by high-energy accelerators such as X-ray converters; all irradiated foods, having damaged DNA or RNA, must be labeled with the Radura symbol). All preserved foods help advancing or retreating forces to survive in hostile war territories in which food has been used as a weapon of war by one or both the opposing forces (e.g., Hitler's retreating forces leaving Moscow while implementing their own scorched earth strategy to stop pursuit).
Source: Encyclopedia of Food & Culture, Gale Cengage 2003.