This is kind of a hard question to measure, because it depends what we are talking about in terms of time scales, what parts of the country we are focusing on, if they are living in cities or the countryside, their class and income level, etc.

There are also a number of mitigating factors. Generally, when people try to compare pre-Revolution and post-Revolution statistics, they take 1913 as the last pre-Revolutionary year, because the First World War began a process of economic mobilization, dislocation and invasion that isn't really a stable "baseline". Added to this is the massive disruption and dislocation that occurred during the Russian Civil War, with the country actually deurbanizing and deindustrializing - scarcity actually meant lots of people left cities for their ancestral villages in this period. The war also led to the 1921-22 Famine.

If we're comparing 1913 to the 1930s, which is when industrialization took off under the Five Year Plans, there is still the 1930-1934 famine to take into account (which did have impacts Union-wide) and massive scarcities of consumer goods - the industrialization was focusing on heavy, primary industry, not consumer goods, and a move of tens of millions to cities old and new for new factory jobs meant extremely crowded and cramped living in urban settings that were not well-supplied with infrastructure. Historian Sheila Fitzpatrick writes that "The average married worker in Moscow [in the mid 1930s] consumed less than half the amount of bread and flour that his counterpart in Petersburg had consumed at the beginning of the twentieth century and under two-thirds the amount of sugar." Of course, there were millions more of these industrial workers in the 1930s, so that's worth taking into account.

Add to all that the massive dislocation and destruction of World War II and the rebuilding efforts, and the continuing urbanization of the country, and by the 1950s things begin to stabilize and improve in terms of living standards, especially under Khrushchev as more resources were devoted to consumer needs (including the mass construction of private khrushchevki apartments - no more communal kitchens and toilets!). This is also about the time (1960 or so) when the population became majority urban for the first time.

If we're really focusing on food in particular, the 1970s and 1980s might be of interest, as average Soviet caloric intake as about as high or higher than that of Americans. There is a larger discussion around the accuracy of that data, and what it does not show in differences of diet or dietary needs in an answer I wrote here.