Long story short: This wasn't the original plan. The original plan, which was in effect for a while, was a variant of the "Morgenthau plan" ( https://en.wikipedia.org/wiki/Morgenthau_Plan#JCS_1067 ). It took two years for them to realize that not only would they be starving Germans (intention), but also the rest of Europe (unintended), and more or less block any economic growth in Europe (+risk Europe falling under the sway of the Soviet Union). So, they reversed their plans and the rest is history (that history includes the Marshall plan).