Nutrient requirements are based on various factors like age, sex, activity and condition of an individual, like for pregnancy and lactation period, infancy, a school going child or an adolescent of either gender. The nutrient demands of an expectant mother and through the lactation period undergo modification from time to time to cater to the demand of the rapidly developing fetus. There is an increased demand for energy, proteins, calcium, iron and folic acid and iodine. At birth the energy demands of the new born are high in view of the rapid growth velocity, which falls slightly after 3 months and thereafter again rises towards the latter half of the first year. The energy and protein requirements are hence based on the velocity of the child\'s growth pattern. The energy requirements have been computed in terms of calories per Kg and the ICMR group (1990) has formulated these requirements based on the FAO/WHO group of 1985. Other simple and quick bed side formulae have been planned for calculating the energy requirements of a child based on his/her body weight e.g. the Holiday and Segar formula. Similar recommendations have been made for other macro and micro nutrients for children of all age groups from 0-18 years.