In the Greek, Romans 14:14 does not have the word unclean. Here is how the Greek reads.
Romans 14:14 “I know, and am persuaded in the Lord Jesus, that nothing is common of itself; except that to him who considers anything to be common, to him it is common.”
There is quite a difference. Common is something contaminated or profane. Scripture is very precise. Any unclean thing is never called food in scripture. Some translations ignore this fact in the Greek text. Food is considered common if it was offered to idols. Scripture never calls food unclean. When you read the word food in scripture, let scripture define it’s own terms. Even the word holy should be understood based on the source of this quote in 1 Peter 1:16 which is Leviticus 11:44.
“Be holy, for I am holy.” 1 Peter 1:16