As I said, the priority of food would go to the industry, it would run on. And the breadbasket of the west was that, a basket of surplus by the time of the war, gone was the famine of the early 30s (things were learned from that). As well as a major population center. It counts both ways.
Remember that entire new cities were constructed in the east, best known is perhaps Tankograd (guess what they made there), with outlying villages and communal farms to feed them. Those that would suffer were the rural population not tied into this sceme of things. But as I said, the leadership couldn't care less about them if the prize was victory, and it would be.