Causes of hunger are related to poverty. There are inter-related issues causing hunger, which are related to economics and other factors that cause poverty. They include land rights, and ownership, diversion of land use to non productive use, increasing emphasis on export oriented agriculture, inefficient agricultural practices, war, famine, drought, over fishing, poor crop yield, etc.
The basic cause of starvation is an imbalance between energy intake and energy expenditure. In other words, the body expends more energy than it takes in. This imbalance can arise from one or more medical conditions or circumstantial situations, which can include:
Medical reasonsAnorexia nervosa
Eating disorder, not otherwise specified
Major depressive disorder
Circumstantial causesChild/ Elder/ Dependent Abuse
Famine – for any reason, such as political strife and war
The main causes of starvation are as follows:Economy; poor people sometimes cannot buy enough foodstuffs and thereby fail to fulfill the caloric demands of the body.
Food scarcity in the society. This causes a decreased supply of food to the whole of the population, and thus mass starvation may occur.
Diseases that can cause rapid weight loss either due to the nature of the disease or the inability of the person to either eat or eat enough due to symptoms including fatigue, nausea, and vomiting. The person may also be the host to a parasite such as an intestinal worm which may take a significant amount of the calories ingested by its host. This effect is exacerbated if the human host is already ingesting far less food than is required to meet their daily caloric intake needs.
Clinical conditions, such as recovering from surgery or burns, etc., in which the person may be too fatigued or incapacitated to eat enough during their period of convalescence.
Early symptoms include impulsivity, irritability, hyperactivity, and other symptoms. Atrophy (wasting away) of the stomach weakens the perception of hunger, since the perception is controlled by the percentage of the stomach that is empty. Individuals experiencing starvation lose substantial fat (adipose tissue) and muscle mass as the body breaks down these tissues for energy. Catabolysis is the process of a body breaking down its own muscles and other tissues in order to keep vital systems such as the nervous system and heart muscle (myocardium) functioning. The energy deficiency inherent in starvation causes fatigue and renders the victim more apathetic over time. As the starving person becomes too weak to move or even eat, their interaction with the surrounding world diminishes. In females, menstruation ceases when the body fat percentage is too low to support a fetus.
Victims of starvation are often too weak to sense thirst, and therefore become dehydrated. All movements become painful due to muscle atrophy and dry, cracked skin that is caused by severe dehydration. With a weakened body, diseases are commonplace. Fungi, for example, often grow under the esophagus, making swallowing painful. Vitamin deficiency is also a common result of starvation, often leading to anemia, beriberi, pellagra, and scurvy. These diseases collectively can also cause diarrhea, skin rashes, edema, and heart failure. Individuals are often irritable and lethargic as a result.
There is insufficient scientific data on exactly how long people can live without food. Although the length of time varies with an individual's percentage of body fat and general health, one medical study estimates that in adults complete starvation leads to death within 8 to 12 weeks. There are isolated cases of individuals living up to 25 weeks without food. Starvation begins when an individual has lost about 30% of their normal body weight. Once the loss reaches 40% death is almost inevitable.
Under normal metabolic conditions, the human body relies on free blood glucose as its primary energy source. The level of blood sugar is tightly regulated; as blood glucose is consumed, the pancreas releases glucagon, a hormone that stimulates the liver to convert stored glycogen into glucose. The glycogen stores are ordinarily replenished after every meal, but if the store is depleted before it can be replenished, the body enters hypoglycemia, and begins the starvation response.
After the exhaustion of the glycogen reserve, and for the next 2–3 days, fatty acids become the principal metabolic fuel. At first, the brain continues to use glucose, because, if a non-brain tissue is using fatty acids as its metabolic fuel, the use of glucose in the same tissue is switched off. Thus, when fatty acids are being broken down for energy, all of the remaining glucose is made available for use by the brain.
After 2 or 3 days of fasting, the liver begins to synthesize ketone bodies from precursors obtained from fatty acid breakdown. The brain uses these ketone bodies as fuel, thus cutting its requirement for glucose. After fasting for 3 days, the brain gets 30% of its energy from ketone bodies. After 4 days, this goes up to 75%. Thus, the production of ketone bodies cuts the brain's glucose requirement from 80 g per day to about 30 g per day. Of the remaining 30 g requirement, 20 g per day can be produced by the liver from glycerol (itself a product of fat breakdown). But this still leaves a deficit of about 10 g of glucose per day that must be supplied from some other source. This other source will be the body's own proteins.
After several days of fasting, all cells in the body begin to break down protein. This releases alanine and lactate produced from pyruvate into the bloodstream, which can be converted into glucose by the liver. Since much of our muscle mass is protein, this phenomenon is responsible for the wasting away of muscle mass seen in starvation. However, the body is able to selectively decide which cells will break down protein and which will not. About 2–3 g of protein has to be broken down to synthesize 1 g of glucose; about 20–30 g of protein is broken down each day to make 10 g of glucose to keep the brain alive. However, this number may decrease the longer the fasting period is continued in order to conserve protein.
Starvation ensues when the fat reserves are completely exhausted and protein is the only fuel source available to the body. Thus, after periods of starvation, the loss of body protein affects the function of important organs, and death results, even if there are still fat reserves left unused. (In a leaner person, the fat reserves are depleted earlier, the protein depletion occurs sooner, and therefore death occurs sooner.) The ultimate cause of death is, in general, cardiac arrhythmia or cardiac arrest brought on by tissue degradation and electrolyte imbalances.
For the individual, prevention consists of ensuring they eat plenty of food, varied enough to provide a nutritionally complete diet.
Starvation can be caused by factors, other than illness, outside of the control of the individual. The Rome Declaration on World Food Security outlines several policies aimed at increasing food security and, consequently, preventing starvation. These include:Poverty reduction
Prevention of wars and political instability
Reduction of economic inequality
Supporting farmers in areas of food insecurity through such measures as free or subsidized fertilizers and seeds increases food harvest and reduces food prices.
Starving patients can be treated, but this must be done cautiously to avoid refeeding syndrome. Rest and warmth must be provided and maintained. Small sips of water mixed with glucose should be given in regular intervals. Fruit juices can also be given. Later, food can be given gradually in small quantities. The quantity of food can be increased over time. Proteins may be administered intravenously to raise the level of serum proteins.
Many organizations have been highly effective at reducing starvation in different regions. Aid agencies give direct assistance to individuals, while political organizations pressure political leaders to enact more macro-scale policies that will reduce famine and provide aid.
According to estimates by the Food and Agriculture Organization there were 925 million under- or malnourished people in the world in 2010. This was a decrease from an estimate of roughly 1 billion malnourished people in 2009. In 2007, 923 million people were reported as being undernourished, an increase of 80 million since 1990-92. It has also been recorded that the world already produces enough food to support the world's population.
As the definitions of starving and malnourished people are different, the number of starving people is different from that of malnourished. Generally, far fewer people are starving, than are malnourished.
The proportion of malnourished and of starving people in the world has been more or less continually decreasing for at least several centuries. This is due to an increasing supply of food and to overall gains in economic efficiency. In 40 years, the proportion of malnourished people in the developing world has been more than halved. The proportion of starving people has decreased even faster.
Historically, starvation has been used as a death sentence. From the beginning of civilization to the Middle Ages, people were immured, or walled in, and would die for want of food.
In ancient Greco-Roman societies, starvation was sometimes used to dispose of guilty upper class citizens, especially erring female members of patrician families. For instance, in the year 31, Livilla, the niece and daughter-in-law of Tiberius, was discreetly starved to death by her mother for her adulterous relationship with Sejanus and for her complicity in the murder of her own husband, Drusus the Younger.
Another daughter-in-law of Tiberius, named Agrippina the Elder (a granddaughter of Augustus and the mother of Caligula), also died of starvation, in 33 AD. (However, it is not clear whether her starvation was self-inflicted.)
A son and daughter of Agrippina were also executed by starvation for political reasons; Drusus Caesar, her second son, was put in prison in 33 AD, and starved to death by orders of Tiberius (he managed to stay alive for nine days by chewing the stuffing of his bed); Agrippina's youngest daughter, Julia Livilla, was exiled on an island in 41 by her uncle, Emperor Claudius, and subsequently her death by starvation was arranged by the empress Messalina.
It is also possible that Vestal Virgins were starved when found guilty of breaking their vows of celibacy.
Ugolino della Gherardesca, his sons and other members of his family were immured in the Muda, a tower of Pisa, and starved to death in the thirteenth century. Dante, his contemporary, wrote about Gherardesca in his masterpiece The Divine Comedy.
In Sweden in 1317, King Birger of Sweden imprisoned his two brothers for a coup they had staged several years earlier (Nyköping Banquet). According to legend they died of starvation a few weeks later, since their brother had thrown the prison key in the castle moat.
In Cornwall in the UK in 1671, John Trehenban from St Columb Major was condemned to be starved to death in a cage at Castle An Dinas for the murder of two girls. The Makah, a Native American tribe inhabiting the Pacific Northwest near the modern border of Canada and the United States, practiced death by starvation as a punishment for slaves.
Many of the prisoners died in the Nazi concentration camps through deliberate maltreatment, disease, starvation, and overwork, or were executed as unfit for labor. Prisoners were transported in inhumane conditions by rail freight cars, in which many died before reaching their destination. The prisoners were confined to the cattle cars for days or even weeks, with little or no food or water. Many died of dehydration in the intense heat of summer or froze to death in winter. Nazi concentration camps in europe from 1933 to 1945 deliberately underfed prisoners, who were at the same time forced to perform heavy labour. The diet was restricted to watery vegetable soup and a little bread, with little or no dietary fats, proteins or other essential nutrients. Such treatment led to loss of body tissues, and prisoners became skeletal, the so-called Muselmann who were murdered by gas or bullet when examined by camp doctors.
Starvation was also used as a punishment where victims were locked into a small cell until dead, a process which could take many days. Saint Maximilian Kolbe, a martyred Polish friar, underwent a sentence of starvation in Auschwitz concentration camp in 1941. Ten prisoners had been condemned to death by starvation in the wake of a successful escape from the camp. Kolbe volunteered to take the place of a man with a wife and children. After two weeks of starvation, Kolbe and three other inmates remained alive; they were then executed with injections of phenol.