i prefer to eat ahead of the flight to maximise sleep time onboard. my experience with this flight usually goes like this...

1. (tired) trying to stay awake for boarding after a long day of work, eat ahead if need to
2. go onboard and try to catch as much zzz as possible, you are not missing much in terms of food if you are in economy, basically go into DND mode
3. (still tired) deplane and go through the 1 hour long immi/luggage process
4. get on a train/bus and nap another hour enroute to the city; prefer train because it's more stable and comfy for napping
5. (not energised, will live) arrive with the maximum rest possible