Is it necessary to know how to feed your mind?

Imam Hasan (a.s.) said:
“عَجِبْتُ لِمَنْ يَتَفَكَّرُ فى مَأكُولِهِ كَيْفَ لا يَتَفَكَّرُ فى مَعْقُولِهِ، فَيُجَنِّبُ بَطْنَهُ ما يُؤذِيهِ و يُودِعُ صَدْرَهُ ما يُرْدِيهِ.”

I wonder about those who think about their body’s food, but do not think about their soul’s food. They keep undesirable food away from their belly, but fill up their heart with destructive subjects.1

Brief Description
Our people are usually quite careful with their food and do not start eating unless they know what it is. They avoid anything that looks doubtful and some go to great lengths to ensure that the body receives good, clean, healthy diet.
Yet, when it comes to the food for the soul, these same individuals will throw caution to the winds. With eyes closed, unaware of the reality, they would have no hesitation in pouring down any mental food into their soul.
They harm their souls by accepting without question the speeches of unsuitable friends, misleading press reports and suspicious or poisonous propagation, and this is very surprising.[divider]
1. Safinat’ul-Bihar 84, article of taste. Bihar Al-Anwar, vol 1, page 218.