This narrative review explores the impact of diet and physical exercise both as a risk factor of central nervous system inflammatory diseases, but more importantly as potential adjunctive disease modifiers in Multiple Sclerosis (MS), Neuromyelitis Optica Spectrum Disorders (NMOSD), and Myelin Oligodendrocyte Glycoprotein (MOG) antibody-associated disease (MOGAD). The gene discussed is OMG; the disease is myeloid sarcoma.