It would vary drastically based on the country. Nazi ideology determined some peoples as superior to others and therefore merited better treatment.

Occupied areas in Western Europe (France, Holland, Belguim) that did not actively resist were often treated quite well excepting standard food and supply rationing.

However, the Nazis saw Slavic people as sub-human and Eastern Europe open to future German colonization. In order to do this, plans were made for the wholesale massacre or starvation of various Slavic and Jewish populations in the East.