The physiological control of appetite is complex. Appetite and food intake are often reduced In the presence of gastrointestinal disease, particularly inflammation, but the mechanisms are not well understood. The principle nutrient sensors in the gut are the enteroendocrine cells (EEC) which respond by secreting gut hormones. These signal to the brain and reduce further food intake. Recent research has assigned key immunological roles to EEC, including expression of components of the innate immune system. Moreover, in the presence of inflammation or infection, EEC number and function are upregulated by adaptive immune responses and play a direct role in the suppression of food intake. These may present tractable targets in developing novel strategies aimed to enhance or suppress food intake.