Thomas Stern is an unabashed locavore, buying everything from beets and basil to lamb and legumes from nearby producers.

“Things like salt and oils are a little harder to source,” the 23-year-old Evanstonian said at a farmers market recently. “But I’d say that about 80 percent of my food is local.”

Stern, who cooks at Fraiche in Evanston, said he chooses local foods largely for taste, higher nutrient values, environmentalism and a connection with the person who grew them.

That philosophy – to try to source food from a within a 100- to 300-mile radius – is fueling “eat local” initiatives across the country. These include Green City Market’s annual “Locavore Challenge,” where hundreds of Chicago-area residents are expected to follow a mostly local diet from Wednesday to Sept. 22.

While such efforts might seem innocuous, a growing chorus of writers, politicians and bloggers is challenging the locavore movement, painting it as naive and elitist at best and dangerous to the livelihood of conventional commodity farmers at worst.

Last spring, Republican Sens. John McCain of Arizona, Saxby Chambliss of Georgia and Pat Roberts of Kansas wrote a letter questioning the Department of Agriculture’s $65 million Know Your Farmer, Know Your Food program, which they said was using public funds to “prop up urban locavore markets.”