​Consider this. The brain works 24 hours a day and needs  a continuous supply of energy.
 
The energy, of course, comes from the food we eat.  According to Harvard Medical School  research what we eat directly affects the function and even the structure of our brains. It certainly affects our mood. Good quality food makes all the difference. Our  diet should contain many vitamins and minerals. Moreover, antioxidants in certain foods are ‘brain food’ and reduce the free radicals which can cause damage to brain cells.
 
Processed and refined foods travel to the brain and the brain finds it difficult to get rid of certain components. Refined sugar is particularly an issue as it can cause inflammation and oxidative stress. Many research papers report a connection between the consumption of foods with a high sugar content and restricted brain function. It can worsen depression and other mood disorders. A leading psychiatrist at Cambridge University confirms that depression can be the result of inflammation of the brain.