The government's December price report showed the cost of food rising while inflation overall held steady. This could worsen the "K-shaped" economy.

Grocery prices rose broadly in December, with five major food categories posting increases, while dining out also became more expensive.

Utility costs added to the pressure, with electricity prices up nearly 7% last year and natural gas posting double-digit gains.

After several years of relatively slow growth, health care costs are beginning to play a larger role in inflation, according to the data from the Bureau of Labor Statistics.