Federal ethanol-fuel policies forced consumers to pay an extra 0.5 percent to 0.8 percent in increased food prices in 2008, and the government itself could end up paying nearly $1 billion more this year for food stamps because of ethanol use, according to a new government report.

The report by the Congressional Budget Office helps answer questions raised by Congress last year as food prices shot up, and some lawmakers questioned the effects of government policies, such as the ethanol mandate.

“Producing ethanol for use in motor fuels increases the demand for corn, which ultimately raises the prices that consumers pay for a wide variety of foods at the grocery store, ranging from corn-syrup sweeteners found in soft drinks to meat, dairy and poultry products,” the CBO said.

The federal government has mandated that a certain amount of renewable fuels be used to replace motor-vehicle fuel, and ethanol from corn is a chief candidate for the U.S. market.