The concept of a functional foetal "appetite regulatory neural network" is a new and potentially critical one. There is a growing body of evidence showing that the nutritional environment to which the foetus is exposed during prenatal and perinatal development has long-term consequences for the function of the appetite-regulating neural network and therefore the way in which an individual regulates energy balance throughout later life. This is of particular importance in the context of evidence obtained from a wide range of epidemiological studies, which have shown that individuals exposed to an elevated nutrient supply before birth have an increased risk of becoming obese as children and adults. This review summarises the key pieces of experimental evidence, by our group and others, that have contributed to our current understanding of the programming of appetite, and highlights the important questions that are yet to be answered. It is clear that this area of research has the potential to generate, within the next few years, interventions that could begin to alleviate the adverse long-term consequences of being exposed to an elevated nutrient supply before birth.