PHOENIX - For 13.6 percent of Arizonans, a trip to the grocery store is a time-consuming and often frustrating venture because those residents live in low-income areas that have few supermarkets, Cronkite News reports.

A new study by the U.S. Department of Agriculture based on 2000 Census numbers found the national average of people living in so-called food deserts was 4.8 percent, far below Arizona??s 13.6 percent.

A so-called food desert suggests that city dwellers have to travel more than a mile to purchase fresh food, while rural residents have to go 10 miles to the store. Rural areas are no longer the food deserts of yesterday. Today??s food deserts tend to be urban, which have about 75 percent of food deserts compared to 25 percent in rural areas. Few grocery stores and lack of adequate public transportation contribute to creating food deserts.

"People don??t get that if you are a struggling or low-income, all of the sudden two miles, especially in the heat of summer, is a big deal," said Brian Simpson with the Arizona Association of Food Banks.

Convenience stores often take up the slack created by a lack of full-service grocery stores. "I noticed this year everyone is selling fresh fruits and vegetables," said Jeff Lenard, NACS spokesman. "We have come a long way with [fresh] food and we still have a long way to go."

Read more about offering nutritious items in convenience stores in NACS Magazine.