When I sit down to work, I keep a small bowl of garlic croutons on my desk. These are little rewards for good ideas and strong lines, Pavlovian pellets to keep my spirits up. Recently, I began to wonder what fuel writers have relied on, and the answers turned out to be all over the culinary map. Walt Whitman began the day with oysters and meat, while Gustave Flaubert started off with what passed for a light breakfast in his day: eggs, vegetables, cheese or fruit, and a cup of cold chocolate. The novelist Vendela Vida told me she swears by pistachios, and Mark Kurlansky, the author of “Salt” and “Cod,” likes to write under the influence of espresso, “as black as possible.” For some writers, less is more. Lord Byron, a pioneer in fad diets as well as poetry, sipped vinegar to keep his weight down. Julia Scheeres, the author of the memoir “Jesus Land,” aims for more temporary deprivation. “When in the thick of writing I minimize food intake as much as possible,” she told me. “I find I work better when I’m a little starved.”