Acts 10 - the vision of the Roman centurion Cornelius, followed by Peter's vision regarding unclean foods, along with 1 Corinthians 8 (which I copied below), sheds light on this issue. Also, Hebrews chapter 9 talks about things on earth being copies or "shadows" of heavenly things, so it may be that many of the OT regulations that don't make much sense to us now fall into this category, and that they point to spiritual realities. I don't know for sure, but it's always helpful for me to see what spiritual lesson God might have for us in these things. Certainly, we must be sure that the exercise of our freedom in Christ does not cause anyone else to stumble, for that is not acting in love.
I Corinthians 8 (NASB)
1Now concerning things sacrificed to idols, we know that we all have knowledge. Knowledge makes arrogant, but love edifies. 2If anyone supposes that he knows anything, he has not yet known as he ought to know; 3but if anyone loves God, he is known by Him.
4Therefore concerning the eating of things sacrificed to idols, we know that there is no such thing as an idol in the world, and that there is no God but one. 5For even if there are so-called gods whether in heaven or on earth, as indeed there are many gods and many lords, 6yet for us there is but one God, the Father, from whom are all things and we exist for Him; and one Lord, Jesus Christ, by whom are all things, and we exist through Him.
7However not all men have this knowledge; but some, being accustomed to the idol until now, eat food as if it were sacrificed to an idol; and their conscience being weak is defiled. 8But food will not commend us to God; we are neither the worse if we do not eat, nor the better if we do eat.9But take care that this liberty of yours does not somehow become a stumbling block to the weak. 10For if someone sees you, who have knowledge, dining in an idol’s temple, will not his conscience, if he is weak, be strengthened to eat things sacrificed to idols? 11For through your knowledge he who is weak is ruined, the brother for whose sake Christ died. 12And so, by sinning against the brethren and wounding their conscience when it is weak, you sin against Christ. 13Therefore, if food causes my brother to stumble, I will never eat meat again, so that I will not cause my brother to stumble.
On a different note, one sentence that particularly caught my eye is in 1 Cor 1:8: "Knowledge makes arrogant, but love edifies." In the secular sense, to edify means "To instruct especially so as to encourage intellectual, moral, or spiritual improvement." In the spiritual sense, it means (to me) to encourage spiritual improvement in another. 1 Thessalonians 5:11 says, "Therefore encourage one another and build one another up, just as you are doing."
Does it profit anyone to show how much I know, if I don't act in such a way as to build that person up in their faith?