In poultry production, a trade-off has been made between growth and efficiency on the one hand, and immune potential and disease resistance on the other. The emerging field of immunometabolism, brought to the fore by research into human metabolic syndrome and cancer, is an opportunity in poultry production to eliminate this trade-off and have both production efficiency and immune robustness. This chapter provides an overview of metabolism and immunometabolism, including the most important links between metabolic and immune pathways. The chapter describes methods of investigating metabolism and addresses the components of feed that lead to inflammation, and how to mitigate this effect. Finally, the chapter discusses the future of research in this field, using examples of how feeding the immune system is already enhancing growth and immune response in poultry.