The human body requires a continuous supply of energy. The energy needs of an average person are 2,500 calories (more precisely, kilocalories) per day. Those people who chronically receive less than 90% of their caloric needs are said to be undernourished. Those who receive less than 80% of their caloric needs are said to be seriously undernourished. Undernourishment is not necessarily the result of low food production in a country. Undernourishment also occurs when individuals do not have the means of obtaining food. This can be the result of unemployment and other economic or political factors. While undernourished individuals may not starve to death, their quality of life is greatly reduced. Their weakened condition also results in low work output, which is part of a vicious cycle of poverty and hunger.