Just to share my experience on BA178 from yesterday. I connected to BA178 having arrived into JFK on AA10 (overnight from LAX) so no pre-arrival breakfast and the paltry food offerings in the BA F Lounge at this time also didn't offer the possibility of a full breakfast either, so I took the flight effectively "empty" from a food perspective. Pictures below of the food provided but in summary I found the quantity adequate.
Starter:
BA178 Starter (Continental platter)
Main:
BA189 Main (Mixed Grill)
Pre-arrival light refreshments:
BA178 Light Refreshment (pre-arrival)