U.S. consumer prices and core inflation both rose higher than expected during January, as food costs jumped and medical care posted the biggest increase in 15 years.

The consumer price index rose 0.2%, the U.S. Labor Department said today. The CPI increased 0.4% in December.

Core inflation, which is consumer prices excluding food and energy costs, increased by 0.3%, after rising 0.1% during each of the three previous months. Unrounded, the core CPI rose 0.174% in January; it rose 0.256% in December.

Economists had forecast a 0.1% increase in consumer prices overall and a 0.2% increase in the core index.

Today’s CPI report said overall consumer prices were 2.1% higher than a year earlier, on an unadjusted basis. Core prices rose 2.7% in the 12 months ending in January 2007.

Energy prices last month decreased by 1.5%, after going up by 4.2% in December. Gasoline prices last month dropped by a seasonally adjusted 3.0%. Natural gas also fell 3.0%. Electricity prices rose 2.0%. Food prices increased 0.7%, the largest rise since 0.8% in April 2005. Costs climbed for vegetables, fruits and dairy products.

The transportation index was 0.8% lower, as gas prices fell and new vehicle prices were flat. Transportation costs in December increased 1.7%. Medical care prices shot up 0.8%, the largest jump since a matching increase in August 1991.

Housing, which accounts for 40% of the index, rose 0.2%, after rising 0.4% in December. Rent climbed by 0.4% and owners’ equivalent rent rose 0.2%. Lodging away from home was up 1.1%. Clothing prices increased 0.3%, while education and communication fell 0.1%. Prices for the category of other goods and services were 0.8% higher in January.

In a separate report, the Labor Department said the average weekly earnings of U.S. workers, adjusted for inflation, decreased 0.3% in January. Average hourly earnings rose 0.2%. Average weekly hours decreased by 0.3%.