"This book compiles the scientific content of the International Symposium on Energy & Protein Metabolism and Nutrition, in Rostock-Warnemünde 13th-18th September 2003.Specialists from all over the world working in energy and protein metabolism research were assembled to discuss scientific matters of physiology, nutrition, immunology and genetics. All scientific contributions, presented as oral communications or posters, are published in this book. Additionally to these more than 150 articles and 10 review papers, presented by invited speakers, give an overview of the state of the art in special research areas of energy and protein metabolism. The book presents latest results in topics of energy metabolism such as environmental aspects of energy homeostasis, dietary and genetic aspects as well as tissue, organ and whole body energy metabolism and methodology. Furthermore this compilation also gives insight in current affairs of protein research, i.e. protein metabolism and microbiology in the gastro-intestinal tract and requirements and post-absorptive metabolism of amino acids. Apart from these specific questions other topics concerning genes and nutrition or modelling and regulation of energy and protein status were of common interest. The intention of these proceedings is to disseminate latest perceptions of energy and protein research and with this to attempt the connection of areas in animal and human life sciences."