Starvation is a severe deficiency in caloric energy
Food energy
Food energy is the amount of energy obtained from food that is available through cellular respiration.Food energy is expressed in food calories or kilojoules...

, nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...

 and vitamin
A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on...

 intake. It is the most extreme form of malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....

. In humans, prolonged starvation can cause permanent organ
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...

 damage and eventually, death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....

. The term inanition refers to the symptoms and effects of starvation.

According to the World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...

, hunger
Hunger is the most commonly used term to describe the social condition of people who frequently experience the physical sensation of desiring food.-Malnutrition, famine, starvation:...

 is the single gravest threat to the world's public health. The WHO
Who may refer to:* Who , an English-language pronoun* who , a Unix command* Who?, one of the Five Ws in journalism- Art and entertainment :* Who? , a 1958 novel by Algis Budrys...

 also states that malnutrition is by far the biggest contributor to child mortality
Child mortality
Child mortality, also known as under-5 mortality, refers to the death of infants and children under the age of five. In 2010, 7.6 million children under five died , down from 8.1 million in 2009, 8.8 million in 2008, and 12.4 million in 1990. About half of child deaths occur in Africa....

, present in half of all cases.