Metformin decreases meal size and number and increases c-Fos expression in the nucleus tractus solitarius of obese mice

► We explored metformin-induced anorexia in diet-induced obese mice. ► Oral metformin transiently reduced meal sizes and persistently meal numbers. ► Oral metformin produced conditioned taste aversion at various doses in obese mice. ► Oral metformin activated neurons within the nucleus tractus solitarius.