They would still have to seize food from the Soviet people to feed their armies.Germany had a lot of things going for it in World War II. Indeed, it seems its real undoing was the ideology of Nazism and how its vicious cuntery drove their enemies into "war of survival" mode. I said in another thread that if the Germans had shown the slightest respect for the rules of war, the Soviet people would have welcomed them with open arms and Stalin's regime would have collapsed.
Domestic German production was insufficient and they actually expected to import food from the East to feed Germany.
Which would cause resentment.
Which then leads to partisans.
And then the vicious cycle begins.
That said, the Germans could have very easily put all those Red Army POWs to work on the newly captured farmlands in the East, or used them as a labor force to change railway gauges and other general, heavy labor tasks instead of locking them in a camp and then starving them to death.
It's a real pity that Schuebner Richter died in the Munich Putsch, because it was only after his death that the whole anti-slavism thing crept into Nazism by way of Himmler and his band of idiots.