When we make a blessing over food, it isn’t because we need to bless the Creator. In fact, the Rav used to say, "The Creator doesn’t need our blessings."
The reason we make any blessing (not only over food) is to awaken our own consciousness. We need to constantly train our mind so that every action we do—from the moment we wake in the morning to the moment our head hits the pillow at night; whether we are at work or school or play, and when we interact with people we meet during the day—every single action is done on a conscious level with intention and with an awareness of the Light of the Creator within and all around us.