This guest post by Tierney Manning is part of Earth Eats' coverage of the 2010 Food in Bloom Conference held in Bloomington, Indiana from June 3-5, 2010.

Not all of the earth's deserts are sandy, arid landscapes.

The regions where it is difficult for people to access fresh and healthy produce -- or noble foods -- are called a food deserts.

Food deserts can be identified by looking at walking distances to noble food stores and farmers' markets. A city's topography is also taken into account because steep hills can make access to food sources more difficult.

For some, shopping for fresh and healthy produce is a chore, but for many others even accessing such produce can be a challenge.

Food Deserts Encourage Unhealthy Eating

The inaccessibility of noble foods can cause consumers to consume more of less-healthy foods -- or fringe foods -- which are more convenient and help them save on time.

Consumption of noble foods is vital to prevent against diet-related diseases and to promote overall well-being.

Besides distance, other causes of food deserts are lack of mobility (personal vehicles, public transportation, etc.) and prices that make it hard for certain demographics to buy healthy foods.

Farmers' Markets Can Help

Below are some images from a study of food deserts in Pittsburgh, Pennsylvania that show change in the size of food deserts when farmers' markets are available (in the summer) compared to the winter months when only grocery stores are available.

The size of the food deserts shrinks during months when farmers' markets are active and produce is available.

These images have been produced by layering a series of maps collected from Pennsylvania Spatial Data Access (PASDA) and Environmental Systems Research Institute (ESRI) in addition to self-collected data. A computer program called Geographic Information System (GIS) aids by using the previous parameters to identify the food desert regions. All maps are the property of Tierney Manning.

Tierney Manning is a recent graduate of Chatham University of Pittsburgh, PA. now living in Chicago, IL. Her background is in environmental science but she has a true passion for food whether it's the creation, chemistry, culinary art, or consumption! To learn more about her research, you can e-mail her at Tierney.Manning@gmail.com.