“You have to eat oatmeal or you’ll dry up. Anybody knows that.” The above claim has never been disproved. It was authored by Kay Thompson and uttered by a 6-year-old girl named Eloise, who lived in The Plaza Hotel in New York with Weenie the dog and Skipperdee the turtle. Ever since I first saw that quote, in the margin by the oatmeal raisin cookie recipe in “The Silver Palate Cookbook,” I’ve wondered what she meant. Perhaps, young Eloise understood that oats absorb a lot of water as they cook, such that when you eat oats, you’re eating mostly water. Or maybe she meant “dry up” as a euphemism for “slow down.” Certainly, oatmeal has a reputation for keeping you going all day like the Energizer Bunny, thanks to the slow release of sugars from the complex carbohydrates in whole oats. Whatever she exactly meant, she was right to cast …