How come the seafood and the pigmeat were suddenly acceptable to eat? What was it that happened?
Jesus declared all foods clean in Luke 11:41 and Mark 7:15,19.
Paul also said that he was convinced by the Lord Jesus that there is nothing unclean of itself, in Romans 14:14.
Why would god change his mind bout that?
Why would he change his mind when only ONE person needed it
God didn't change his mind...He simply gave the dietary food laws to the Jewish people as a part of the covenant that He had made with them.
In Genesis 9, it is clear that Noah was allowed to eat all manner of meats.
And, while for those who seek to be justified through law-keeping, their works, or their personal merits, they are required to obey all of Moses' law perfectly from conception into eternity; yet it is also true that God did not give His law to the Gentiles (specifically the dietary food laws).
While all the world will be found guilty before God on the basis of the law of Moses (Romans 3:19-20) as they are judged by it as a standard of righteousness.
And therefore, for the one seeking to be justified on the basis of personal merit (whether they are Jew or Gentile), they are required to obey the food laws (Galatians 3:10, James 2:10, Matthew 5:48).
So the food laws still apply to the unbeliever as condemnation.
For the believer, it is the spirit of the law that governs him and he has been delivered from the condemnation of the letter (Romans 7:6).
Personally, I do my best to obey the food laws, not in order to obtain or keep my salvation; but rather as an expression to the Lord that I love Him. Abstaining from those savoury meats, which I love, is my way of saying to Jesus,
"I love you more than anything".