Being provided with food is part of the essential care of a person. This is vital for existence. As God is our father, we (can) ask him to be always fed. This is why the request for our "daily bread" is included in the prayer.
Explanation:
The best example is when Jesus took a couple of pieces of bread, fish and wine and was able to feed the whole village, and then some. Taking care of everyone, as a father would.
