In the US meal breaks for actors are regulated by the Screen Actors Guild/American Federation of Television and Radio Actors (SAG/AFTRA) and are usually provided by the Craft Services Department.
According to the Union rules found here
The performer must be given the first meal break within six hours from the time of first call. The provisions for meal periods are the same for all performers.
Please note that, for the purpose of synchronizing performer and crew meal-time, the performer may be given a non-deductible meal of 15 minutes free from all activity within two hours of the performer’s call time. An announcement should be made and a notation indicating the start and finish time of the non-deductible meal must be on the production time report. The following is then allowable:
The first meal break would then be due six hours from the end of the non-deductible meal.
The second meal break must be called within six hours from the time of call back from the first meal break.
The Producer can deduct actual time up to one hour spent at meals.
A twelve minute grace period to set up provided the six hour period is not already extended due to camera being in the course of photography.
Meal penalty payments for violations of either meal period are:
for the first half-hour, or fraction thereof $ 25
for the second half-hour $ 35
for each half-hour thereafter $ 50
When you see the craft services tables piled up with food keep in mind this is not only for the actors but also for the crew which usually outnumbers actors 3 to 1.
As for the starving actor image, standard background actors are paid $148/day plus travel cost and any overtime. Not bad but if you only work for a week you better have another job.