Monday, October 29, 2007

Diet for Small Planet may be most efficient if it includes dairy and a little meat

By Susan Lang, Cornell Chronicle, Oct. 4th.

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, Cornell researchers suggest.

The study, published in the journal Renewable Agriculture and Food Systems, is the first to examine the land requirements of complete diets. The researchers compared 42 diets with the same number of calories and a core of grains, fruits, vegetables and dairy products (using only foods that can be produced in New York state), but with varying amounts of meat (from none to 13.4 ounces daily) and fat (from 20 to 45 percent of calories) to determine each diet's "agricultural land footprint."

"A person following a low-fat vegetarian diet, for example, will need less than half (0.44) an acre per person per year to produce their food," said Christian Peters, M.S. '02, Ph.D. '07, 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."

"Surprisingly, however, a vegetarian diet is not necessarily the most efficient in terms of land use," said Peters.

The reason is that 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. A large pool of such land is available in New York state because for sustainable use, most farmland requires a crop rotation with such perennial crops as pasture and hay.

Thus, although vegetarian diets in New York state may require less land per person, they use more high- valued land. "It appears that while meat increases land-use requirements, diets including modest amounts of meat can feed more people than some higher fat vegetarian diets," said Peters.

Read more (Cornell Chronicle)