Unfortunately, that's not true. Millions didn't.
For example, in the early years of the USSR, collectivization of agriculture caused a massive famine in the early 1930s, killing several million people.
Things went even worse in China during the so called 'Great Leap Forward', the most devastating economic experiment of all time. According to most estimates, about 40 million(!) people died at that time from hunger. Some even think it's more like 80 million, a death toll higher than both world wars combined.
In the 1970s, the USSR could only avert a massive famine by importing grain from... guess who? Yes, the United States.
And the most recent famine in North Korea from 1994 to 1998 killed at least several hundred thousand people. Up to this day, malnutrition seems to be a major problem in North Korea.
East Germany, especially East Berlin was a special case. Due to its geographic location, the USSR used it as some kind of store front, trying to put socialism in best light. As a result, the supply situation in East Berlin and GDR was much better than in other countries of the Eastern Block. But it was still very bad in comparison to West Germany.