<human>:  When did the US government begin rationing food in the book ‘Food in World War I’?
<bot>: Rationing of food in the United States began in 1917, when the US entered the war. The United States was not the only country to experience rationing during World War I, but it was the most severe. Rationing of food was also imposed in other countries, including Britain, France, and Germany. Rationing was a way to conserve scarce food resources, especially meat, sugar, and fats.