Judith C. Thalheimer, RD, LDN, managing editor of Tufts Health & Nutrition Letter, answers: “After the inedible husk is removed from an oat grain, the resulting groat (inner kernel) can be cut into smaller pieces or steamed and flattened with a roller. Steaming and rolling breaks the grain’s structure down and creates a greater surface area so the oats cook more quickly and have a softer, more consistent texture. Quick or instant oats generally undergo further processing, such as precooking and then drying.
“All forms of oats are nutritious, fiber-rich whole grains. They are naturally low in saturated fat and sodium and are a good source of phosphorus and selenium and a very good source of manganese. Oats also are a good source of fiber, including beta-glucan, a soluble fiber associated with reducing blood cholesterol levels and colon cancer risk.
“The nutritional content of instant oats is the same as other types of oats (steel-cut/Irish, Scottish, and rolled/old-fashioned). Instant oats are digested more quickly than regular oats. They therefore raise blood sugar levels faster. Instant oats are frequently found in products that contain added sugars and flavorings.
“If you have the time, try steel-cut (sometimes called Irish) oats. They have the most intact structure and will likely keep you full the longest and have the least impact on your blood sugar. If you do not like the texture of steel-cut oats, rolled oats (sometimes called regular or “traditional”) are a softer, quicker cooking option. These can be soaked overnight in a liquid of your choice, such as milk or soy milk, to create a no-cook, creamy, porridge- or pudding-like grab-and-go breakfast. Top with berries, nuts, banana, cinnamon, a dollop of plain yogurt, or anything else that suits your tastes, and enjoy a healthy, hearty “instant” breakfast.”