Clinical and experimental data, together with epidemiological studies, have suggested that the pathogenesis of multiple sclerosis (MS) might involve factors that link the immune system with metabolic status. Moreover, recent research has shown that leptin, the adipocyte-derived hormone that controls food intake and metabolism, can promote experimental autoimmune encephalomyelitis, an animal model of MS. In patients with MS, the association of leptin with disease activity has been dissected at the molecular level, providing new mechanistic explanations for the role of this hormone in MS. Here, we review the intricate relationship between leptin and other metabolic modulators within a framework that incorporates the latest advances linking the CNS, immune tolerance and metabolic status. We also consider the translational implications of these new findings for improved management of MS.