Ramen noodles have supplanted tobacco as the most valuable commodity among prisoners in the US, as cost-cutting leaves jails struggling to feed inmates.

A decrease in both the quality and quantity of food in state prisons has left the cheap snack in high demand, a study has found.

Michael Gibson-Light, a doctoral student in sociology at the University of Arizona interviewed nearly 60 inmates and staff at one state prison and analysed investigations into other institutions nationwide.

He found that the burden and cost of care was shifting away from prison systems and on to prisoners and their families or friends.


"Prisoners are so unhappy with the quality and quantity of prison food that they receive that they have begun relying on ramen noodles - a cheap, durable food product - as a form of money in the underground economy," he said.

"Because it is cheap, tasty, and rich in calories, ramen has become so valuable that it is used to exchange for other goods."

The Federal Bureau of Prisons reported that states spent about US$48.5 billion on jails in 2010, marking a 5.6 per cent decline compared with 2009.