Some ways that the government controlled the economy in World War 1 was to allocate scarce materials, coordinated purchasing, determined priorities, encouraged the development of new facilities, and fixed prices. They also standardized production to effect savings and it occasionally granted exemption from the antitrust laws to promote efficiency.
European nations relied heavily on American wheat and sugar exports. Food administrator Herbert Hoover got farmers to bring additional land under cultivation by offering to purchase agricultural commodities at high prices. At the same time he urged customers to observe “wheatless,”
“meatless,” and “porkless” days. He also asked grocers to restrict each person’s sugar ration to two pounds per month. He ruled that restaurants could not serve bread until after first course, also use sugar cubes instead of using sugar bowls. A coal shortage was threatened so Garfield ordered factories producing civilian goods to close down for a few days to observe “heatless” days as a conservation measure. Due to massive transportation tie-up in 1917 the head of railroad administration, William McAdoo integrated rail schedules, limited passenger traffic, modernized equipment, and increase the amount of uniform track gauge.
The American Century by Walter LaFeber