Ramen noodles have overtaken tobacco to become the most valuable commodity in U.S. prisons, Doctoral candidate in the University of Arizona’s school of sociology Michael Gibson-Light’s new report stated.

During his studies Gibson-Light interviewed fewer than 60 inmates. The scientist claims that the tendency to use noodles as prison currency is noted also in other researches on the subject, BBC reported.

 “Ramen is easy to get and it’s high in calories,” Gibson-Light said.

“A lot of them, they spend their days working and exercising and they don’t have enough energy to do these things. From there it became more a story, why ramen in particular”, the Guardian reported.

As the study says, Ramen can be exchanged for various goods or services in prison. Due to the long term of storage it is ideal currency.

“One way or another, everything in prison is about money. Soup is money in here. It’s sad but true,” a prisoner said.

As Gibson-Light believes, that this happened due to the fact that  the quality and quantity of food given to prisoners fell sharply.

On Monday, the U.S. Department of Justice announced plans to close all private prisons in the country.

Recent check revealed that in comparison with state in private prisons there are low level of safety and high level of violence.