As per God changing his mind, God did not change his mind. Under the old covenant, there were specific foods that were unclean for JEWS to eat.
The UNCLEAN FOODs were still unclean until the new covenant was enacted.
God did not change his mind. The gospel of Christ had always been the original intent of God. He enacted the law as a placeholder until the time when his original intent would be manifested.
Gal 3
7 Know ye therefore that they which are of faith, the same are the children of Abraham.
8
And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed.
Notice that Paul is telling us that God already spoke about the gospel to Abraham (in thy "seed" that is Christ) even before the law was given.
Continuing...
Gal 3
16 Now to Abraham and his seed were the promises made.
He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.
17 And this I say,
that the covenant, that was confirmed before of God in Christ, the law, which was four hundred and thirty years after, cannot disannul, that it should make the promise of none effect.
Paul is showing us God's original intent was to save man through the gospel of Christ Jesus and God had already preached to Abraham this gospel. (The law coming 430 years after CANNOT DISANNUL the promise that was already given)
Continuing...
Gal 3
19
Wherefore then serveth the law? It was added because of transgressions, till the seed should come to whom the promise was made; and it was ordained by angels in the hand of a mediator.
Paul is telling us "why was the law given then since it cannot disannul the promise already made to Abraham?"
And he gives the answer right there: "till the seed should come to whom the promise was made"
The law was a placeholder until the time of reformation
Heb 9:10 Which stood only in meats and drinks, and divers washings, and carnal ordinances,
imposed on them until the time of reformation.
So we see that God did not change his mind.
In fact way back in
Gen 3:15, he had spoken of the seed to come.