Everywhere Jessica Hardy turned, it seemed as if someone was telling her to eat quinoa. The message, she recalls, seemed to be: "If you just eat quinoa for the rest of your life, you'll die happy."

After visiting yet another restaurant where quinoa appeared on the menu in "five different forms," she says, the Vancouver writer last year decided she'd had enough of "people's blind devotion" to the bead-size food. She banged out a piece for a local news website, called "Five Reasons to Hate...