Abstract: A method for treating depression in a human subject, which comprises administering for a first time period a fasting mimicking diet (FMD) component providing less than 50% of the normal calorie intake of the subject with both protein restriction and sugar restriction; and administering for a second time period a re-feeding diet component that provides 60-100% of the normal calorie intake of the subject; the fasting mimicking diet component and the re-feeding diet component are administered for multiple cycles, and the subject undergoes a psychotherapeutic treatment for the whole duration of the multiple cycles.