Are you feeling sad without any reason?
Is your mood always dull and not prefer to be out under the sun?
If yes, then you might be suffering from a mental illness.
For the most of the people, the food that has been consumed determines their overall mental behavior.
Imagine a lion which is fierce due to it's carnivorous diet and an elephant which is calm most of the time due to it's herbivorous diet.
Food becomes us, and a bad food is surely precipitates a detrimental outcome.