Boby is correct. The so-called "Hunger Plan" is a post-war construct, based on a prejudicial interpretation of a detailed plan for extracting food from occupied Soviet territory, written most probably by Herbert Backe in May 1941.
If one reads the entire paper, one sees that it is analysis of the amounts of food produced in various parts of the Soviet Union and the quantities available for use by Germany. The single reference to the starvation of "tens of millions" occurs in a throwaway line, and is presented by Backe as a likely result of the diversion of surplus Soviet food production to Germany and its sphere of influence in Europe. There is however nothing in the paper to support the thesis that the purpose of the food-extraction plan was to exterminate a part of the Soviet population through starvation.
An English translation of the entire paper can be found in this publication:
Karl Brandt and others, "Germany's Agricultural and Food Policies in World War II: Vol 2, Management of Agriculture and Food in the German-Occupied and other Areas of Fortress Europe : A Study in Military Government", published by Stanford University Press 1953.
The plan presented by Backe in May 1941 based largely on his theory that European Russia was divided into two distinct zones, a food-surplus area (essentially Ukraine and the North Caucasus) and a food-deficit area (mainly Belarus and Northern Russia), and that there was a flow of food from the former area to the latter. He postulated that if the two zones could be sealed off from each other, the flow of food from the food-surplus area could be diverted to Germany. The side-effect of such a diversion would be a large-scale food shortage in the food-deficit area, which would probably lead to mass starvation unless a large part of the population of that area moved to Siberia (which was in fact a food-surplus area).
The problem with Backe's theory is that there was not a neat division of the German-occupied territory into food-surplus and food-deficit areas, and the proposed sealing-off of the two areas from each other could not work in practice. The historical fact is that there was not a massive famine in the Soviet territories that came under German occupation. What did occur was a large-scale movement of population from the cities to the countryside where food and work were available; the city population consisted to a large extent of peasants who had moved to the cities in the 1920s and 30s, so it was relatively easy for them to move back to the countryside.
The authors of the above book, in the section on German food policies in the occupied Soviet territories, point out that the amount of food extracted by Germany from those territories during the period of occupation was less than the amount that had been exported from them in the last years before the war, suggesting that the German extractions would not have led to food shortages of sufficient magnitude to cause mass starvation among the local population, unless there was a massive decline in production. That is probably the reason why the huge famine predicted by Backe did not occur, at least not on the scale he had thought possible.
As has been pointed out by Gerlach and other historians who have studied German food policies in occupied Soviet territories, when the predicted famine did not occur, and there was no mass mortality of the civilian population from starvation during the winter of 1941-42, the German authorities did not resort to alternative ways of exterminating the population under their control (except in the case of the Jews). That in itself suggests that extermination of the Soviet population by starvation was not an aim of Backe's food-extraction plan, rather that the predicted famine was a side-effect.
There was in fact a considerable mortality from starvation in the non-occupied parts of the Soviet Union, for example in Central Asia. That starvation had two major causes:
1. Some of the major food-producing areas, eg Ukraine and to a lesser extent the North Caucasus, were under German occupation and their food surpluses were not available to the non-occupied part of the Soviet Union.
2. A large part of the population of the territory that came under German occupation, particularly the urban population, had been hastily evacuated to the East, to the Southern Ural region and central Asia, where there were insufficient food supplies for them.