Despite efforts to limit the availability of junk food in schools, many elementary school students still have been able to buy sugary snacks at their schools, a study says.

The report, published in the Archives of Pediatrics & Adolescent Medicine, says that by the 2009-2010 school year, about half of all public and private elementary school students could buy food from competitive venues on campus (vending machines, school stores, snack bars or a la carte lines), and sugary foods were available to almost all students with access to these options.

In contrast, only about two-thirds of the students with access to competitive food venues were able to buy salads, vegetables or fruit.

Researchers Lindsey R. Turner and Frank J. Chaloupka from the University of Illinois at Chicago gathered data through surveys of public and private elementary schools from 2006-2007 to 2009-2010.

"Many U.S. elementary school students have access to competitive foods on campus, particularly in the South," the study concludes. "Although lower-fat options are available, students can also purchase various less healthy options that are high in sodium, fat or sugar."