While "foodshed" may bring to mind a small structure designed to hold food, it is a fair amount more interesting, if less intuitive, than that. Simply put, a foodshed is a geographic area that includes where a food is produced, where it is transported, and where it's consumed. It includes the land it grows on, the routes it travels, the markets it goes through be they farmers markets or supermarkets, and the tables it ends up gracing.
In short, a foodshed is every touchpoint of a type of food or foods.
The History of "Foodshed"
First used in the early 20th century to describe the global flow of food, "foodshed" has recently been resurrected to discuss regional and local food systems and efforts to create more sustainable ways of producing and consuming food.
The Modern Foodshed
A local or regional "foodshed" could be defined in a variety of ways. A simple 100-mile radius, for example, is often used in "eat local" campaigns. Those are making an attempt to define and limit a foodshed for a population (or at least give some guidance to make people more aware of where their food is grown).
Workable, sustainable foodshed mappings tend to take into account the length and ease of travel, the geographic distribution of a population, where and how any natural water sources travel, and the innate productivity of the land.
More sophisticated foodshed models take that basic information and layer in the need and use of different types of fertilizers, labor impacts, socio-economic fall-out from labor practices, environmental impacts of growing food, and more to create full-spectrum pictures of how food is affected by and affects the area where it's grown, travels through, and feeds.
Different Kinds of Foodsheds
Foodshed is most often used to describe the area from which a population gets its food, it can also be used to refer to the area that provides a single type of food. This would be true of particularly local products, such as dairy or some fresh produce.
Maps of different foodsheds can compare from where different places source their food, as well as compare the large and small impacts of similar foods grown, distributed, or consumed in different areas.
In contemporary systems, foodsheds can be wide and wandering, with arms of an area's foodshed stretching across the country and around the globe. Studying foodsheds and comparing them is one way to find areas that can be made more sustainable while still meeting the dietary needs of different populations.