In his 1945 article “The Economic Organisation of a P.O.W. Camp,” the British economist R.A. Radford recounted his experiences within the informal system of barter among prisoners at Stalag VII-A, a German camp on the outskirts of Munich during the Second World War. Using supplies delivered by the Red Cross, some prisoners moved between different nationalities’ encampments, buying tea for cheap from the French (who tended to prefer coffee) and then selling it to the British (whose affection for tea is a matter of centuries-old lore). Meanwhile, imprisoned Gurkha soldiers from South Asia sought out tins of vegetables and bartered them for corned beef.

Radford’s account, which was compellingly retold by Ray Fisman and Tim Sullivan in their recent book The Inner Lives of Markets, explains that, in the absence of paper money, prisoners had to pick another currency to enable their transactions: cigarettes. “A ration of margarine might be bought for seven cigarettes, the equivalent, for instance, of one and a half chocolate bars, and so on,” Fisman and Sullivan write. “For the most part, prices were well known and consistent among the camp’s many huts that acted as local markets.”

Be they in wartime Bavaria or modern-day America, a surprising number of prisoners have lived in systems whose internal economies have centered on tobacco. However, according to a study released on Monday by Michael Gibson-Light, a doctoral candidate in the University of Arizona’s school of sociology, cigarettes have been supplanted in the United States by instant ramen. Gibson-Light argues that this dynamic has less to do with the national drop in smoking rates or the banning of cigarettes in some prisons and more to do with prisons’ finances. At the state prison where he conducted his study, budget cuts led to a reduction of the caliber and total number of meals that prisoners received, which meant that the practical value of ramen skyrocketed. “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 wrote in a press release accompanying his paper, which was presented at the American Sociological Association’s convention, in Seattle.  

In the study, Gibson-Light chronicles how a package of ramen, which costs 59 cents at the prison’s commissary, commands far greater value than its actual worth as it gets exchanged for different items. For example, thermal clothing, which runs over $11 in the commissary, is worth six packs of ramen, or a total value of $3.54, in a trade. What’s to stop prisoners from stocking up on ramen from the commissary and trading it for items that are worth more in dollars? It can be a shortage of funds—some prisoners simply don’t have access to that amount of cash—but it also is the case that the prisoners Gibson-Light studied had access to the commissary only once a week, and even then could lose commissary privileges as a disciplinary measure.

And besides, it might be dangerous to sit on a cache of such a valuable item: Gibson-Light also traces the accumulation of debt over borrowed ramen, which leads to disputes and violence. “I’ve seen fights over ramen,” one prisoner told him. “Who the fuck gonna fight about ramen noodles? That’s 15 cents on the outs!”

Gibson-Light added that other investigations into prison exchanges have indicated a trend away from tobacco and toward noodles. In his study, he brings up a dynamic of what’s called “punitive frugality,” in which prisons, in saving money by serving lower-quality food, pass “the burden and cost of nutrition and other needs on to inmates and their families” by compelling prisoners to seek out alternate forms of sustenance. Citing data from the U.S. Bureau of Prisons, Gibson-Light’s report highlights a 5.6 dip in prison spending between 2009 and 2010, in the wake of the Great Recession, as well an overall failure to match corrections spending with the increasing ranks of inmates since the early 1980s. At the prison where the study took place, wages for prison work also haven’t risen since the 1970s, making money a limiting factor. What’s striking is that the most sought-after item in American prisons has shifted from cigarettes, coffee, envelopes, or stamps—none of which are essential—to food, a necessity.

Speaking of punitive frugality, prison food in the United States already has a controversial history as a sanctioned form of punishment. Late last year, New York State announced that it would cease feeding Nutraloaf, or “Disciplinary Loaf” to prisoners in solitary confinement after activists campaigned against the starchy and maligned foodstuff. As of 2014, Nutraloaf was thought to be a disciplinary staple on the state and local levels in over a dozen states.

Before it became prisoners’ currency or the cliche fare of college students, instant ramen was created with the goal of feeding starving citizens in postwar Japan. “Peace will come to the world when all its people have enough to eat," said its inventor, Momofuku Ando. And, as Karen Leibowitz noted in 2011, over the myriad possibilities, a poll conducted in Japan in 2000 concluded that instant ramen was the most important invention of the 20th century. Dispiritingly, ramen is proving to be an invention crucial to life in many 21st-century American prisons, too.