It is increasingly realised that the nutritional environment during early life not only affects the course of development but also establishes the settings of both physiological responses to the environment and the range of environments in which the offspring can live healthily in later life. When environmental challenges exceed an individual’s ability to respond healthily, risk of disease increases. We describe this as an individual mismatched to their environment, and the greater the degree of mismatch the greater the risk of disease. Hence balanced nutrition in pregnancy and childhood is not only important for the health of the mother and the growth of her child, but also establishes some of the fundamental processes which determine risk of later chronic disease including the metabolic syndrome, cardiovascular disease and osteoporosis. We are now rapidly learning how these processes are established in early life, especially the role of nutritionally-induced epigenetic processes (e.g. DNA methylation and histone methylation and acetylation) which produce sustained effects on gene expression determining the offspring’s cardiovascular, metabolic and neuro-endocrine responses, as well as growth of key organs such as the heart, kidney, liver and pancreas. The developmental responses additionally determine the offspring’s body composition, in terms of skeletal muscle, bone and fat; these track into later life to affect risk of glucose intolerance, obesity and osteoporosis. What is striking is that these processes start to be induced even in very early development, and are then modulated by later interactions between fetus and its mother via the placenta, and then between the mother and infant during suckling. In this way factors in addition to maternal diet, such as her stature and body composition, stress and exercise levels and behaviour can influence the long-term health of her child. New evidence suggests that the effects can be passed to more than just one successive generation. In addition effects on metabolic homeostasis and obesity in females lead to increased risk of gestational diabetes, which in turn induces deleterious effects on their offspring. There are several ways in which these insights are relevant to developed and developing societies. They include: ● rapid transitions in diet and levels of physical activity ● changes in a woman’s body composition produced by dieting or by being overweight ● excessive control of weight-gain in pregnancy in some societies such as Japan ● teenage pregnancies ● increasing age at first pregnancy ● increasing proportion of primiparous pregnancies with reductions in family size ● changes in breast-feeding practices. These socio-cultural processes, many involving changes in nutrition, will influence the degree of mismatch between the next generation and their environment. The consequences of this for incidence of non-communicable, chronic diseases are very substantial. Acknowledgements: MAH is supported by the British Heart Foundation