USSR doubled life expectancy in just 20 years. A newborn child in 1926-27 had a life expectancy of 44.4 years, up from 32.3 years thirty years before. In 1958-59 the life expectancy for newborns went up to 68.6 years. the Semashko system of the USSR increased lifespan by 50% in 20 years. By the 1960's, lifespans in the USSR were comparable to those in the USA:
https://en.wikipedia.org/wiki/Demographics_of_the_Soviet_Union
https://www.rand.org/pubs/research_briefs/RB5054/index1.html
Quality of nutrition improved after the Soviet revolution, and the last time USSR had a famine was in 1940s.
By 1983, they had become completely food sovereign and eating better than Americans (according to the CIA)
https://www.scribd.com/document/430076844/CIA-RDP84B00274R000300150009-5-pdf