Recognition of the importance of good nutrition in early childhood has led to an increased acceptance of the "first 1000 days" (from conception through the second year of life) as a critical window of opportunity for ensuring children have good health throughout life, with associated benefits in other areas. There are powerful arguments to say that investments made during this early period are both a foundation for better long-term development and the most efficient point of intervention to lessen the impacts of childhood poverty.

Early under-nutrition is reflected in children's physical growth trajectories, with early disadvantage stunting children's development from a very young age. However research from cohort studies is increasingly identifying that children's growth trajectories are not fully fixed in infancy. Some children are able to recover from early stunting, while others fall behind after an initial period of normal growth. Understanding what determines changes in children's post-infancy growth gives insights into the patterns of development (and interventions) which may foster more sustained healthy growth. This brief summarises key evidence to date from a series of research studies using Young Lives data to analyse children's growth, and concludes by drawing out implications for policy.