Regulatory peptides, both hormones and neurotransmitters, are the key expertise of this group of about 30 scientists and scientists in training. They are crucial to the control of mammalian energy balance. We use multiple techniques, from targeted adult gene manipulation through hypothalamic explants to human infusion studies, to demonstrate the workings of the hypothalamic circuits regulating appetite and energy expenditure. We have discovered the important role of peripheral peptide hormonal signals, for example from the gut, in regulating appetite. This is being exploited to identify the cause of excessive (or deficient) fat stores in man. These gut hormones are being used to develop powerful new ways of regulating appetite. They have the advantage that they appear safe for long term therapy. With over 1,000 people dying prematurely from obesity in the UK each week, and no effective treatment, such original approaches are long overdue and spur on our work.