Even if you're about to go restaurant hopping, sometimes gorging after a short period of not eating actually fills you up faster, I find. Better to have a light bite to keep your stomach active, or...Something.
As for that ending, I wonder if anyone missed the reference? In Japan, most of the country calls it 'Mac' for short, but 11 prefectures refer to it as 'Macdo', mostly concentrated in the kansai (osaka) area.
I believe that she's just making excuses about the 'local cuisine' thing since it's still mcdonalds in the end...Well, Wcdonalds?