Is eating at restaurants such as McDonald's or KFC forbidden?

The Quran and Sunnah indicate the permissibility of eating the meat of the People of the Book if they slaughter it according to Islamic law, based on the Almighty's saying: "And the food of those who were given the Scripture is lawful for you." However, what they kill by unlawful methods such as electric shock or strangulation is not permissible to eat, because it is carrion, based on the Almighty's saying: "Forbidden to you are carrion." Since it is known that the People of the Book nowadays do not slaughter according to Islamic law, it is not permissible to eat from restaurants like McDonald's or KFC unless one verifies that the meat was slaughtered according to Islamic law.