CHAMPAIGN, Ill. – A recent University of Illinois study suggests that supermarkets are the primary source of “junk” food for U.S. adults, far surpassing convenience stores, vending machines, entertainment venues and fast-food and full-service restaurants.

The study says that access to healthy foods in a supermarket does not hinder Americans’ consumption of empty calories. In fact, the study found, U.S. adults buy the bulk of their sugar-sweetened beverages and nutrient-poor discretionary foods at supermarkets and grocery stores.

According to a press release, the new findings challenge the “food desert” hypothesis, which posits that a lack of supermarkets and grocery stores in some communities restricts people’s access to healthy foods.

“More than half of the sugar-sweetened beverages and two-thirds of discretionary foods are purchased in supermarkets and grocery stores,” said Ruopeng An, University of Illinois kinesiology and community health professor, who led the study. “Supermarket purchases of these items are about two to four times as large as all the other sources—fast-food restaurants, full-service restaurants, convenience stores, vending machines and other locations—combined.”

The press release continues that the food desert hypothesis led the U.S. government to spend almost $500 million since 2011 to improve access to supermarkets and grocery stores in underserved communities. States and municipalities also have made efforts to increase the supply of healthy foods, offering financial incentives to build new grocery stores or to increase the amount of fresh food available in convenience stores and gas stations, for example.

“It is true that supermarkets also are the largest source of healthy food,” An said. “But we can’t be naïve and think that people only purchase healthy food from supermarkets. They also buy all this junk food from supermarkets and grocery stores.”

Adding fruit and vegetables improves the diet, An said. “But from the standpoint of obesity prevention, it is only helpful if people replace junk food with healthy food,” he said. “We don’t see from our data that the presence of a supermarket has a preventive effect on people’s obesity or their junk-food intake.”