I read this in al-Baghawees Tafseer of verse 5:5: "{... and the food of those who were given the Scripture is lawful for you...} means the meat of the Jews and Christians and whoever entered their religion of the other nations before the Prophecy of Prophet Muhammad, sallallaahu 'alayhi wa sallm. As for those who embraced their religion after the advent of the Prophet Muhammad, sallallaahu 'alayhi wa sallam, then it is not lawful to eat."
Does this mean according to al-Baghawi's opinion that those who accept Judaism and Christianity after Muhammad, sallallaahu 'alayhi wa sallam, was sent, we cannot eat their food and marry their women? And that the allowance to marry their women and eat their food was only to those Jews and Christians before Muhammad, sallallaahu 'alayhi wa sallam, was sent?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

Indeed, Al-Baghawi did state this in his Tafseer (interpretation of the Quran), and it is the view of some scholars, but the correct opinion according to most scholars is contrary to this.

Shaykh Al-Islam Ibn Taymiyyah said in Daqaa’iq at-Tafseer: “In conclusion, we say that the pronouncement that the People of the Book who are mentioned in the Quran are those whose grandfathers entered that religion before it was abrogated (by Prophet Muhammad ) is a weak statement, and the pronouncement that ‘Ali ibn Abi Taalib implied this is also weak. Rather, the correct opinion that is absolute is that the man being from the People of the Book or not is an independent ruling and everyone who adopts the religion of the People of the Book is one of them, whether his father or grandfather embraced their religion or did not embrace it, and whether he embraced it before the ruling was abrogated or after it was abrogated. This is the view of the of the majority of the scholars such as Abu Haneefah and Maalik, and it is the explicit view of Ahmad although there is a well-known difference of opinion about it among Ahmad's companions. This view is also the adopted view among the Companions (of the Prophet, sallallaahu ‘alayhi wa sallam) and I do not know any difference of opinion among the Companions in this regard.”

Allaah Knows best.