When Adam was banished from the Garden of Eden, he was also sent to till the earth from which he was taken, to separate the good from the evil in it, the sorting out being a corrective process.
Afterwards, there was the eating of the fruits of his labor, and the enjoyment of this harvest is also an act of choosing and discriminating.
As in prayer, one gives thanks for the nourishment that enables one to raise the sparks of holiness hidden in the food.
Because there is a circle of life in which man’s place is crucial, he has to sort out things in the material world and then he is enjoined to raise that which he has selected to a higher level, even to holiness.
By sanctifying his food, he is using his special relation to the Divine for this purpose of correcting the reality of the world.
–Rabbi Adin Steinsaltz