Starvation is a severe deficiency in caloric energy intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death. The term inanition refers to the symptoms and effects of starvation.According to the World Health Organization, hunger is the single gravest threat to the world's public health. The WHO also states that malnutrition is by far the biggest contributor to child mortality, present in half of all cases. Undernutrition is a contributory factor in the death of 3.1 million children under five every year. Figures on actual starvation are difficult to come by, but according to the Food and Agriculture Organization, the less severe condition of undernourishment currently affects about 842 million people, or about one in eight (12.5%) people in the world population.The bloated stomach, as seen in the picture to the right, represents a form of malnutrition called kwashiorkor which is caused by insufficient protein despite a sufficient caloric intake. Children are more vulnerable to kwashiorkor whose advanced symptoms include weight loss and muscle wasting.