The hippocampus is the brain’s memory centre and is vital for remembering new information. Neurons in the hippocampus form connections that are constantly being reorganised, a process we call neuroplasticity. This enables us to learn and form memories in response to the constant influx of information in our dynamic world. Junk food filled diets also reduces key brain chemicals required for neuroplasticity, impairing memory.
Research also shows that people who eat lots of junk food also perform badly in memory tests compared to those who eat healthily, irrespective of body weight (i.e. you don’t have to be overweight for these foods to impact your brain’s health).