Michael Gibson-Light, a doctoral candidate at the University of Arizona’s school of sociology, published a study in which he interviewed 60 inmates at one state prison and analyzed nationwide investigations into other institutions. What he found, as the Guardian U.S. writes, was that ramen noodles are becoming an increasingly valuable commodity.

Gibson-Light discovered that, in the early 2000s, the prison where he conducted his interviews had swapped out its private food preparation firm for one that was cheaper in order to cut costs. The quantity and quality of the food inmates were served dropped as a result.

How American Prisons Became a Bizarre Tourist Mecca

Before the switch, prisoners at the prison studied received three hot meals every day. Today, they get two hot meals and one cold meal on weekdays, and two meals a day on weekends. And, according to prisoners’ personal accounts, they don’t get enough. “I save all my meals to eat at once so I can actually get full,” one inmate told Gibson-Light. Additionally, the researcher was warned against eating the food by corrections officers—who said it might give him food poisoning.

What followed was an increase in value of ramen noodles at the prison studied, as well as at similar U.S. penal institutions. Gibson-Light writes that noodles have even become more treasured than cigarettes and—in institutions where tobacco isn’t as popular—stamps and envelopes. He found that the overall trend has been leaning toward food, but ramen is particularly popular because it’s “easy to get and it’s high in calories.”