The fat body plays a vital role in the proper functioning of invertebrates, contributing to their metabolic processes and resilience. It serves as the central tissue for metabolism integrating signals, regulating molting and metamorphosis and producing hormones that govern the overall body function and immune system protein synthesis. Thanks to this multifunctionality, the fat body is responsible for the metabolism of basic compounds: lipids, carbohydrates and proteins, storing them in the form of reserves (protecting against weather conditions, starving, etc.) and “post-trials” metabolites. In this tissue the remodeling process takes place, which enables the metamorphosis of insects. Also, the fat body is the place of the synthesis of immune proteins, some hormones, pheromones and vitellogenin. Understanding its physiology has, therefore, become an important element of research on insects in the context of general health.