Many methods and technics have accumulated a considerable mass of data about the mechanisms which control food intake and energetic loss. After a presentation of the most relevant signals sent by peripheral organs to the central nervous system : Glucose, triglycerides; from adipocytes : Leptin; from pancreas: Insulin, pancreatic polypeptide, amylin, enterostatin; from digestive tract: Ghrelin, cholecystokinin, peptide Y Y3-36 we consider, especially at the hypothalamic level, their interpretation by neurones whose transmitters are either neuropeptides such as: Neuropeptide Y Agouti Related Peptide, Cocainel Amphetamine Regulated Transcript, Melanin Concentrating Hormone, alpha Melanocyte Stimulating Hormone, orexins/hypocretins, octadecaneuropeptide, nociceptin/orphanin FQ, opioid peptides, Interleukin 1, galanin, urocortin 2, Neurotrophic ciliary factor, Glutamate, or monoamines such as : Dopamine, Norepinephrin, serotonin, GABA, histamine, acetylcholine. After this brief synopsis one should not be surprised that this so complex system which regulates feeding may be affected by various disorders; however one may be amazed by such a scarcity of drugs to influence it; whatever may be it predicts many new pharmacological strategies in this respect.