Data from clinical trials, retrospective and cross-sectional studies have quantified the metabolic changes associated with long-term use of antiepileptic drugs (AEDs). AEDs can be associated with weight gain or weight loss, although most are weight neutral. Weight gain is not only a cosmetic problem but also a risk for obesity-related vascular disorders. Weight loss may compromise growth in children/adolescents. This review discusses the possible contribution of peripheral and central hormones/neuropeptides (as leptin, insulin, adiponectin, neuropeptide-Y, ghrelin and galanin) and pathways that influence energy balance in the pathogenesis of weight changes with AEDs. As AEDs may influence weight, physicians have to properly select and characterize the suitable AED as an initial step or modify the existing AED if it compromises patient’s health.