Although it has been argued that undernutrition and its consequences for child development are irreversible after the age of 2, the evidence in support of these hypotheses is inconclusive. This working paper investigates the impact of nutrition at different periods from conception to middle childhood on cognitive achievement in early adolescence using data from Ethiopia, India, Peru, and Vietnam. In order to address estimation problems the paper develops a conceptual framework that delineates the channels through which child health impacts cognitive development and uses exogenous variation in nutritional status arising from weather shocks.  

Results suggest that child growth both before and after the first 1,000 days is responsive to weather shocks and impacts cognitive achievement in early adolescence. The research also finds that part of the effect of early growth on later cognitive achievement manifests through growth in interim periods. Another novel result is that parental investment responses to a change in child health depend on the timing of this change.

These findings have important policy implications. On the one hand, results indicate that nutrition early in life is important for physical growth and cognitive development in subsequent stages of childhood, but on the other hand they suggest that nutrition-promoting investments after infancy and early childhood can act as a remedy for early nutrition and cognitive deficits and protect from nutritional insults in later stages that may also lead to developmental setbacks. Overall, the evidence suggests that nutrition-promoting interventions that start early in life and continue to subsequent stages of childhood, combined with support in other areas such as cognitive stimulation and parental involvement, may hold the most promise for the promotion of child development.