This is because the divine loaf is the one stepping down out of the universe and he granting substance to the world order.
Jhn 6:33 For the bread of God is he which cometh down from heaven, and giveth life unto the world.
Interesting and Hidden Aspects:
The meaning here isn't quite as poetic as the English translation. Christ is using some concepts that he has developed well over the course of his teaching.
The concept of "divine bread" being something more than "worldly bread" goes back some of Christ's earliest words in the Bible, Mat 4:4, where "bread: is first defined as "that which gives life."
Interestingly, the term used for "he which cometh down" (katabainô) is neither the word usually translated as "come" in the NT (eiserchomai), nor is it the term used in Mat 4:4, as "proceeds out" (ekporeuô). The word used here has more of a sense of choosing to do something. It is also different than the word Christ as been using to describe himself as "sent out" by the Father (apostello). It is in the form of a present participle, that is, a verb taking the role of a noun, in this case, a masculine noun.
In the alternative, the alternative renders the word translated in the KJV as "heaven" as "the universe" simple to emphasize the point that Christ use the term to mean everything that wasn't worldly. This word, basically meaning "sky" is not used the way "heaven" is used in the modern Church as the place of heavenly reward. However, Christ clearly identifies it as "the realm of God" in the sense that the Father is a universal God, God over all.
The word translated as "giveth" is also a present participle, that is, a verb acting as a masculine noun.
The word translated as "life" has the more general meaning of "substance." In this context, describing "bread," it could easily be translated as "sustenance," the substance giving life.
Though translated consistently in the NT as "the word," the term kosmos has the primary meaning of "order." Christ uses it to both "the-powers-that-be" governing worldly society and, as in this case, more generally the way the world is organized.
ὁ καταβαίνων (part sg pres act masc nom) "He which cometh down" is from καταβάτω (katabainô), which means "dismount", "come down", "go down," and "step down." It is a metaphor for "attain" and with the word "end" (telos) means "attaining one's end."
καὶ "And" is from kai, which is the conjunction joining phrases and clauses, "and," or "but." After words implying sameness, "as" (the same opinion as you). Used in series, joins positive with negative "Not only...but also." Also used to give emphasis, "even", "also," and "just."
ζωὴν "Life" is from zôê (zoe), which means "living", "substance", "property", "existence," and, incidentally, "the scum on milk." It has the sense of how we say "make a living" to mean property. Homer used it more to mean the opposite of death.
"Unto the world" is from kosmos, which mean "order", "good order", "ruler", "world order", "universe," and "the world of men."