You know how it goes; you see someone in the morning, you say ‘good morning’. The same applies in German. You can say Guten Morgen. But after that… at some point in the later morning, people switch from saying Guten Morgen and instead say Mahlzeit. That means, literally translated. Meal time. Mahlzeit is what you say when you are about to start eating a meal, kind of like the French bon apetite. But strangely enough, it is also used as a greeting. If you pass someone in the corridor at work and they are carrying food, chewing something, or hell, even look like they might be heading to the canteen, you say Mahlzeit to them, instead of hello.
It’s hard to get used to, but I’m getting there.
an aussie in austria 
Considering the insane importance that Lunch has in the Austrian mindset, it’s no wonder that even the greetings evolve to incorporate Mittagsessen!
My favourite thing was eating lunch early and then watching the landscape become like a post apocalyptic wasteland – devoid of human life before the stroke of 12!
I know what you mean – I get weird looks when I announce that I’m going to cook an evening meal… everyone else uses up their calories at lunch!
Haha! We never quite got over the Australian need for a proper dinner, which always invited comment!
I am not over it either. I do find it strange though that when they go out for dinner they are perfectly happy eating a large meal and starting very late!