Malnutrition can lead to developmental challenges; some are not reversible even with proper nutrition. Key is to prevent young children from being malnourished and break the cycle of poverty. Caused by either acute or chronic undernutrition. Underlying factor in majority of child deaths. Primary causes are diarrhoea, pneumonia, measles, influenza. Malnutrition impacts on infant & child physical development. Energy and protein critical to human development. Accounting for other factors: genetic and environmental. Science of measuring the human body and its parts". Based on comparison of human body measurements to a reference standard steps: measurement of individual, compare individual to reference group, determine nutritional status. Delayed menarche used as indicator of energy deficiency reduced years of fertility. Intellectual development causes: maternal undernutrition, child undernutrition (brain development, fatigue) impacts: cognitive functioning, intellectual capacity. Micronutrient deficiency: iodine (iq reduced by 13. 5 points) and iron (iq reduced by 9. 0 points) Energy deficiency: fatigue impact less strong than for cognitive development.