Author Vicki Robins, of Whidbey Island, Washington, was a self-described “local food dabbler” for a long time. She would shop at the farmer’s market if she had the time, and she joined a community-supported agriculture program—which she later quit because she didn’t use all the vegetables that came her way. Then, in September 2010, she accepted a challenge from a farmer friend to eat only foods sourced within 10 miles of her home. Though she…