Today making the simplest of grocery selections have become an intricate affair of ethical choices, ranging from free range, grain fed, cage free, slow food to considering the food miles it took to get an item from farm to plate.
Now you can add the 'food print' to that list.
Food print is the amount of land needed to supply one person's nutritional needs for a year.
With the world population projected to grow from 6 billion in 1999 to 9 billion by 2042 according to the US Census Bureau the earth capacity to agriculturally sustain this growth rate becomes increasingly important.
The term comes from a Cornell University study, published in the journal Renewable Agriculture and Food Systems. It is the first to examine the land requirements of complete diets. It found that a low-fat vegetarian diet is very efficient in terms of how much land is needed to support it. But adding some dairy products and a limited amount of meat may actually increase this efficiency.
It was conducted in the New York state area comparing 42 diets with the same number of calories and a core of grains, fruits, vegetables and dairy products. They only used food that can be produced in New York state, but with varying amounts of meat and fat to determine each diet's "agricultural land footprint."
"A person following a low-fat vegetarian diet, for example, will need less than half an acre per person per year to produce their food," said Christian Peters, a Cornell postdoctoral associate in crop and soil sciences and lead author of the research.
"A high-fat diet with a lot of meat, on the other hand, needs 2.11 acres."
However don't think if you're a vegetarian you are in the clear.
"A vegetarian diet is not necessarily the most efficient in terms of land use," says Peters.
Fruits, vegetables and grains must be grown on high-quality cropland, he explained. Meat and dairy products from ruminant animals are supported by lower quality, but more widely available, land that can support pasture and hay. Most farmland requires a crop rotation with such perennial crops as pasture and hay.
Food prints differ from area to area, depending not on how fertile the land is, but also on the eating habits of the inhabitants.
Ultimately Jennifer Wilkins, senior extension associate in nutritional sciences who specialises in the connection between local food systems and health says that, "Consumers need to be aware that foods differ not only in their nutrient content but in the amount of resources required to produce, process, package and transport them."