The only food outside security that I know of is an espresso stand on the baggage claim level. EWR's C has almost nothing outside security.

To get into NYC from C:
* buy a NJ Transit ticket to NY Penn Station at the amtrak/NJ Transit machines on the mezzanine level in C, right by the escalators to the monorail
* take monorail to the EWR train station
* take a train into NY Penn Station- not all NJ Trainsit trains go that far, so check the schedules first:

NJ Transit

The clickable route map is the easiest way to get just the schedules that you need.