Instant noodles are displacing the time-honoured jailhouse currency tobacco as inmates barter in calories rather than cigarettes to supplement substandard prison grub, according to a new study cited by the Guardian newspaper.

Instant soups with ramen noodles are high in calories and have gained favour among inmates as the quality and quantity of US prison food declines due to cost cutting, the UK-based newspaper said, citing study author Michael Gibson-Light.
A doctoral candidate at the University of Arizona's school of sociology, Gibson-Light interviewed about 60 inmates at one state prison as part of a wider study on prison labour, the Guardian said. “Soup is money in here. It’s sad but true,” one inmate reportedly told the study author.