Growth is the traditional means of assessing the impact of newborn nutrition. We argue that this approach is flawed as the optimum pattern of postnatal growth after extremely preterm birth is unknown and both growth restraint and growth acceleration are associated with beneficial as well as adverse outcomes. Clinical trials examining nutritional regimens should be designed to achieve specific patterns of postnatal growth. Clinical practice should include the systematic capture of neonatal nutritional intake. As the ultimate goals are adult health and wellbeing, long-term follow-up is essential.