As for the prohibition of food I quote below one relevant Qur'anic
"Forbidden to you (for food) are: dead meat, blood, the flesh of swine, and that on which hath been invoked
the name of other than Allah; that which hath been killed by strangling, or by a violent blow, or by a headlong fall, or by
being gored to death; that which hath been (partly) eaten by a wild animal; unless ye are able to slaughter it (in due form);
that which is sacrificed on stone (altars); (forbidden) also is the division (of meat) by raffling with arrows: that is impiety..."(5:3)
Your doubt is why God should prohibit any kind of food, while God is the One who has created everything. Well, everything
has a purpose in Gods scheme. If God tells His obedient servants (that is to say, those humans whom are willing to follow
His laws) that they are prohibited from eating a particular kind of food, then the duty of His servants is just to follow
That is a test from God, which those who love God follow literally. It is not a question of certain
things having been created by someone other than God. God is the Creator of everything; God is in command of everything; God
is the Lawmaker and the Lawgiver; He has the Dominion and the Power of command.
This is the Islamic view of the universe
and our duty is to understand His commands and obey. It is a matter of submitting to his Will, not a matter of who created
what is prohibited and who didnt. I hope this brief answer gives you an idea about the wisdom of yielding to the only One
Who is worth surrendering to in complete submission.