The difference between our fasting and the fasting of the People of the Book is the Suhūr meal

In this Hadīth, the Prophet (may Allah's peace and blessings be upon him) informs that the difference between the Muslim fasting and the fasting of the Jews and the Christians is the Suhūr, a pre-dawn meal eaten by Muslims, but not by the People of the Book. Muslims are recommended to have this meal so as to be different from the Jews and the Christians, and to comply with the Sunnah, and also to obtain the good and blessing contained therein, as related in the Hadīths.

The People of the Book start their fasting at midnight, and so they eat until this time, not before dawn. Muslims are required under Shariah to act differently from non-Muslims.