2011 World Hunger and Poverty Facts and Statistics by World Hunger Education Service: "Protein-energy malnutrition (PEM) is the most lethal form of malnutrition/hunger. It is basically a lack of calories and protein. Food is converted into energy by humans, and the energy contained in food is measured by calories. Protein is necessary for key body functions including provision of essential amino acids and development and maintenance of muscles.
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Number of hungry people in the world
925 million hungry people in 2010"