What are the reasons for the radical change in the course of the Second World War?

The reasons for the radical change in World War II include:

1) Continuous assistance with food and equipment from the United States;

2) The numerical superiority of the Soviet troops;

3) A series of major defeats of German troops near Moscow, Stalingrad and finally the Kursk Bulge;

4) German troops had practically no reserves that would allow the war to be waged on an equal footing.

Thus, from the second half of 1943, the fascist troops were constantly retreating.