U.S. consumer prices were under wraps last month, especially when food and energy prices were stripped out.

The consumer price index increased 0.2% in April, the U.S. Labor Department said today. Excluding food and energy, it advanced 0.1%. Wall Street economists had expected a 0.2% rise in both the headline and core indexes.

Consumer prices rose 3.9% on a year-over-year basis, down slightly from the prior month. The core CPI grew a more modest 2.3% compared to April 2007. Over the past three months, core inflation rose at only a 1.2% annual rate.

The year-to-year core increase is slightly above the U.S. Federal Reserve’s presumed comfort zone of around 1.5% to 2%. The Fed’s preferred gauge, the core price index for personal consumption expenditures, is closer to that range at 2.1% annual growth through March.

Energy prices were unchanged last month after jumping 1.9% on March, according to today’s report, though with oil prices hitting record highs this month, that will likely change in May. Gasoline prices fell 2% last month, but natural gas prices spiked 4.8%.

Food prices rose 0.9% on the month, the biggest rise since 1990, and 5.1% versus one year ago.

Medical care prices, meanwhile, increased a modest 0.2%, while clothing prices advanced 0.5%. Transportation prices fell 0.7% on the month, as airline fares and new vehicle prices both fell.

Housing, which accounts for 40% of the CPI index, was up 0.3%. Rent increased 0.3%. Owners’ equivalent rent advanced 0.2%.

In a separate report, the U.S. Labour Department said the average weekly earnings of U.S. workers, adjusted for inflation, fell 0.5% in April, suggesting incomes aren’t keeping pace with prices, which could weigh on consumer spending.

Average hourly earnings increased 0.1%, and average weekly hours were down 0.3.