Over the last 15 years, a number of long-term health risks associated with reduced fetal growth have been identified, including cardiovascular diseases, hypertension, dyslipidaemia and type 2 diabetes. A common feature of these conditions is insulin resistance, which is thought to play a pathogenic role. However, despite abundant data in the literature, it is still difficult to trace the pathway by which fetal events, environmental or not, may lead to increased morbidity later in life. To explain this association, several hypotheses have been proposed pointing to the role of a detrimental fetal environment, a genetic susceptibility or an interaction between the two, and of the particular dynamic changes in adiposity that occur during catch-up growth. The relative impact of early postnatal events in relation to fetal growth has to be considered for designing health policy strategies for early interventions aimed at decreasing disease risk throughout life.