To be honest, if on a Loco carrier 12 hour day you do not have any time throughout the day to take a short break to be able to comfortably eat a meal away from the work environment then you have a serious company rostering issue that needs to be taken up with the company.
Such tight rostering issues are both illegal and immoral. All employers have a legal mandate to afford you, the employee, adequate breaks throughout the working day. Anything else where you get worked constantly without breaks is a flight safety hazard that should be taken up, through the Captain (who IS responsible) to the company management.
Failure to do so becomes the individuals problem as they are not bringing the issue to the notice of the company. I have had to delay flights due to the CC requiring a break to get lunch/dinner etc. Whilst it can be annoying it is also a requirement which I see as good leadership from the senior CC member looking after their team on my behalf.