Oct. 12 (HealthDay News) -- Kids who shop at the corner store before or after school purchase nearly 360 calories worth of food and beverage, on average, during each visit, according to a study of Philadelphia students.

Junk food is the most popular purchase, including chips, candy and sugar-sweetened beverages such as soft drinks, the study found. Results are in the November issue of Pediatrics.

For the study, researchers conducted more than 800 surveys of students in grades 4 through 6 in urban areas of Philadelphia. They talked to kids outside corner stores immediately after they made purchases and looked at what they bought in order to collect nutritional data.

More than eight in 10 students surveyed were from families with incomes that were low enough to qualify for free or reduced-price meals at school, the surveys showed.

More than 50 percent of the kids said they shopped at corner stores once a day, five days a week, and nearly 30 percent visited the stores twice a day -- before and after school.

The kids spent a bit more than a dollar, on average, and purchased 356 calories worth of food. Chips made up a third of all purchases, the study authors noted. But with a dollar, they said, the kids could buy an 8-ounce drink, a small bag of chips, candy, gum and a popsicle.

"This is the first study to show what children purchase from corner stores before and after school," lead researcher Kelley Borradaile, of the Center for Obesity Research and Education at Temple University, said in a news release from the Robert Wood Johnson Foundation. "It is troubling that so little money buys so many calories. Corner stores are an important part of the urban landscape, and they have a significant impact on the amount and quality of calories children consume."

What should be done? "Promoting items like water, single-serving snacks and fresh fruits are small changes that could yield a significant impact on the quantity and quality of children's food intake," Sandy Sherman, director of nutrition education at the Food Trust, suggested in the news release.

The study was part of an initiative aimed at boosting the amount of fresh fruit and other healthy snacks on store shelves in Philadelphia, Baltimore and Oakland, Calif.

SOURCE: The Robert Wood Johnson Foundation, news release, Oct. 12, 2009