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). This evidence concerns the gene MOG and multiple sclerosis.