With them would go 137,000 wheeled vehicles, 4,200 fully tracked vehicles, and 3,500 cannons. Also assembled were prodigious amounts of supplies. Each American soldier in Normandy got six and one-quarter pounds of rations a day, each German three and one-third. On the other hand, a German rifle company’s small-arms ammunition scale was 56,000 rounds, an American company’s 21,000.
[…]
By September 1944, German aircraft fuel production was only 10,000 tons, while the Luftwaffe’s minimum monthly demand was 160,000 tons. These deficiencies reduced the menace of new German jet-engine fighters, now being introduced.
Plentiful food supplies probably helped diplomatically. I presume that the local Europeans would trust Americans who gave gifts of chocolate and cigarettes more than hungry Germans who would demand extra food. The army marches better with full stomachs.
The fuel consumption of motorized vehicles is a related set of issues that deserves careful examination.