Here's an argument local-food activists might consider: that demand for organic food in the developed world is aiding farmers in Africa. According to this Reuters article, African farmers are growing organic food for export.

"In Europe farms which have used chemicals on their land have to wait for three years while their land is cleansed before they get organic certification," said Amarjit Sahota of consultants Organic Monitor.

"As Third World farmers do not use agricultural chemicals they can get certification almost immediately."

African farmers were gaining from the trend.

"We are seeing the switch across the board with a range of crops in countries like Kenya, Uganda, Tanzania and Egypt," he said. "This is almost entirely being produced for export."

"I estimate there has been a 9,000 percent increase in organic farming in Africa in the last four years and a 1,000 percent increase in Latin America."

What the article doesn't explain, and which needs further investigation, is whether the farmers are actually benefiting from this trade in premium agricultural goods.

But this raises questions: Does an emphasis on buying local, to reduce food miles, stamp out just the sort of trade the developing world is seeking? Should it? Can a desire to support local farmers be balanced with trade that helps those in the Third World? And if so, How?