INCAP Guatemala nutrition study (1969–1977)
Researchers in four Guatemalan villages gave a high-protein supplement to one group and a control drink to another across pregnancy and early childhood.
Children in supplemented villages grew taller and performed better on cognitive tests in childhood.
Follow-ups into adulthood found higher wages and educational attainment.
It established that early nutrition shapes later human capital, the same logic the Delhi package builds on by adding health and stimulation components.
