Keith Godfrey (MRC Epidemiology Lifecourse Unit) evaluated the epigenetic processes that underpin metabolic programming and the development of obesity. Around conception, during fetal life and in infancy and childhood, nutritional and other normal environmental variations affect development with lasting effects on later health and chronic disease risk. There is now evidence that excessive gestational weight gain has lasting effects on offspring adiposity, while maternal vitamin D insufficiency is associated with impaired bone development and postnatal gain in adiposity. Poor quality diets are common in women with low educational attainment, and relate to fetal adaptations and childhood body composition. Moreover, the mother’s diet affects fetal liver development, with an imprudent diet associated with decreased fetal blood flow through the ductus venosus and increased liver blood flow. Potential interventions include diet and exercise prescription together with counselling and maternal vitamin D supplementation.