The conclusion is that Americans ate too much, meaning there’s more food available than necessary, whereas Soviet citizens ate a better amount, but it consisted largely of less expensive foods like potatoes. Americans ate a lot more fish and meat (21% vs 8%), which is likely a marker for prosperity differences between average citizens. The difference was pretty small (~250 calories according to that document), so I’m not exactly sure what your point is.

In the USSR, we have a few examples of famine, such as Holodomor, and the US stepped in during the famines in the 1920s. Between those two periods, we see millions of deaths, somewhere between 5-10 million.

On the flipside, during the Great Depression in the US, few people starved and life expectancy likely rose. During this period, the US went through the Dust Bowl crisis, which doesn’t seem to have resulted in starvation (though it did result in displacement).

So from what I can tell, the US had much more consistent food availability throughout even the worst of crises, whereas the Soviet system seemed to struggle. Granted, starvation wasn’t really a thing after 1947, so the USSR seems to have at least met minimum expectations for food production. This is a decent Reddit thread on it, and the result is essentially that farmers don’t like collectivization much at all, and sometimes that resulted in huge problems like food shortages, and the USSR often resorted to imports when production wasn’t enough:

A system of state and collective farms, known as sovkhozes and kolkhozes, respectively, placed the rural population in a system intended to be unprecedentedly productive and fair but which turned out to be chronically inefficient and lacking in fairness… However, Marxist–Leninist ideology did not allow for any substantial amount of market mechanism to coexist alongside central planning, so the private plot fraction of Soviet agriculture, which was its most productive, remained confined to a limited role. Throughout its later decades the Soviet Union never stopped using substantial portions of the precious metals mined each year in Siberia to pay for grain imports, which has been taken by various authors as an economic indicator showing that the country’s agriculture was never as successful as it ought to have been.

So basically, the USSR was dependent on food production in the west because its own production was often lacking. So not only did the US have more than enough food production for its own population, but it also had enough to help out the USSR (e.g. this massive grain deal).