Fed Chairman Ben S. Bernanke and his chief deputies on the FOMC-Fed Vice Chairman Janet Yellen and New York Fed President William C. Dudley-have said in recent speeches that the committee's leadership believes the threat from accelerating prices will prove "transitory." Even so, policy makers have been bumping up their forecast for 2011 core inflation, which excludes food and fuel. The April projection is about 1.5%, compared with about 1.2% in January.

Restaurants have projected menu increases of 1.8% during the next six months, the most in a year, according to research by RBC Capital Markets. The amount depends on the type of food they serve, said Larry Miller, an RBC analyst in Atlanta. In the same period, the companies are forecasting a rise of at least 3.2% in their commodity costs, the research showed.

Rising Unemployment

The industry's ability to pass along higher input costs depends on diners' ability to pay more. The unemployment rate rose to 9% in April after dropping to 8.8% in March, still below a post-recession peak of 10.1% in October 2009. The Bloomberg Consumer Comfort Index fell to minus 46.2 in the week ended May 1, the second consecutive weekly decline.

Customer traffic still has improved from last year and "trends have been decent in terms of demand, so restaurants have a little more confidence to raise prices," Miller said.

The Standard & Poor's Supercomposite Restaurants Index, which includes McDonald's Corp., The Cheesecake Factory Inc. and 25 other companies, has risen by 43% since December 31, 2007, while the S&P 500 Index has declined by 8%.

McDonald's boosted menu prices in the U.S. by 1% in March, Chief Financial Officer Peter Bensen said on an April 21 conference call. The Oak Brook, Ill.-based fast-food chain had resisted such a move since 2009, said Miller, who upgraded McDonald's stock in January to "outperform" from "sector perform."

'Inflationary Environment'

"Our upgrade was driven by the belief that fast-food models, like McDonald's, thrive in a modest inflationary environment and that they would be able to successfully implement price increases in 2011," Miller said.

BJ's Restaurants Inc. expects to boost menu prices for the full year by about 3% to offset rising food and energy costs, Chief Executive Officer Gerald Deitchle said on an April 20 conference call. Like McDonald's, the Huntington Beach, Calf.-based company didn't raise prices the past few years at its namesake brewery, pizza and grill chains, Deitchle said.

Cheesecake Factory, based in Calabasas Hills, Calif., is monitoring input costs after rolling out a 0.7% rise at its 150 casual-dining restaurants earlier this year, Chief Financial Officer Douglas Benn said on an April 20 conference call. The company currently projects a further boost of at least 1.4% later this year, he said.