The WHO advocates that all newborn infants are exclusively breast-fed for the first 6 months of life, followed by a period of weaning, with appropriate complementary feeds, which is recommended to continue until the child's second birthday. The period of lactation from the mother's perspective of up to 2 years for each child, represents a considerable period of adult life. Adequate protein intake during lactation is important - if a woman's dietary intake of protein is inadequate, her own lean mass will be depleted to support the growth of the infant. Currently, dietary protein intake recommendations are based on nitrogen balance studies conducted in men and recommendations for breast-feeding women are extrapolated from these studies, and there is little breast-feeding specific data.