On different days, on might find cooked rice, chili dogs, sandwiches, soup, and other food that could be made into a meal. He explained to me that putting the other stuff in first allows one to get more in and is less likely to spill all over with the wiener on top. He had a point, and I've done it his way ever since. I always notice when a fast food place or coffee shop does it the old way. On feature films, which usually have a lot more extras, extras have their own craft service table, usually with inferior snacks.
Most TV shows have the same craft service table for use by everyone.
To summarize, in spite of some negative thoughts I have expressed about the differences that non union extras occasionally encounter, between catered meals and craft services, extras are pretty well fed while on the set.