"When you have eaten and are replete, then you shall bless"
Rabbi Chiya speaks here about, "And satisfies the desire of every living thing," indicating that the person who has eaten must bless God in order to give joy above. Rabbi Chizkiyah says that even one who is drunk may say the Blessing After a Meal, because the blessing is tied to satisfaction on this level, but a person who is drunk must not pray, because prayer rises higher, to that place where there is neither eating or drinking.
There is a link between our daily bread and our spiritual lives, which on this earthly level, feed each other constantly and interactively. The blessing of a meal awakens divine sparks of Light within the food so that we may nourish both our bodies and our souls. Otherwise, all we receive from the meals we eat is the one percent physical matter of the food. We miss out on the remaining 99 percent - the eternal spiritual nourishment. This passage extracts all the sparks of Light from all the foods eaten by man throughout time. Further, we are uplifted to the highest levels of the spiritual atmosphere, where the Light is so all-embracing that there is no need of food or drink.