All types of oatmeal are 100% whole grain and offer similar amounts of protein, fiber, vitamins, and minerals. What differs is the cooking time, shape (rolled or steel-cut), texture (chewy or smooth), and whether or not they are all natural or fortified with B-vitamins and iron. The type of oatmeal people prefer depends of course on your taste preference and available cooking time. There are 8 main forms of oats:
Whole Oat Groats.
Steel Cut / Irish Oats.
Scottish Oats.
Rolled / Old-Fashioned Oats.
Quick Oats.
Instant Oats.
Oat Bran.
Oat Flour.
Steel-cut oats take 20 to 30 minutes to cook. They have a chewier texture than rolled oats. Despite popular belief, steel-cut oats are nutritionally similar (not superior) to rolled oats. Old-fashioned oats (rolled oats) cook in 5 to 10 minutes and have a firm texture. They can be eaten uncooked with milk, like any dry cereal, or in the form of muesli or overnight oats. Quick-cooking oats are ready in a minute on the stovetop, they cook quicker and have a smoother texture. Instant oats cook quickly in the microwave. They are pre-cooked, rolled thin, dried, and then rehydrated to be eaten. Benefits from eating oatmeal Oats are a “safe” choice for a pre-event meal. They are low in certain fibers to prevent GI problems. Oats contain a type of soluble fiber (beta glucan) that makes cooked oats gluey—but can be beneficial for endurance athletes. Beta glucan slows the absorption of carbs over 2 to 3 hours, helping you feel satiated for a long time. Beta-glucan helps reduce the risk of heart disease if you eat oats in the context of a heart-healthy diet. To achieve this benefit, the daily target is 1 cup dry rolled oats or ½ cup dry steel-cut oats most days of the week. Oats have about 5 grams protein per ½ cup dry serving. A good protein target for breakfast is at least 20 grams, so cook the oats in 1 cup milk (dairy milk, 8 g protein, or soy milk, 7g protein) and stir in 2 tablespoons of peanut butter or ¼ cup of nuts (8 g pro), and you’ll have a perfect breakfast! Fortified oats offer extra iron, a mineral important for vegan and vegetarian athletes. Read the Nutrition Facts label for information on iron in the oats you buy. Oats have some fiber, but only about 4 grams per serving (1/2 cup dry rolled oats, 1/4 c dry steel-cut oats). Given the daily fiber target is 25 to 38 grams (achieved by only 10% of women and 3% of men), oats make a small contribution—but more fiber than if you were to have just eggs for breakfast. While naturally gluten-free, oats are often processed in a factory that also processes (gluten-containing) wheat. If you have celiac disease, you want to make sure you buy gluten-free oats How much oatmeal to boost performance Oats are versatile. You can cook them in water—or preferably in milk, to add protein, calcium, and creaminess. The suggested ratio is 1 cup (8 oz) of liquid for each half-cup rolled oats or ¼ cup steel-cut oats. For a savory option, cook oats in broth, season with soy sauce, or top with sriracha. Or add some cheese and spinach when cooking, then top the oatmeal with a poached egg. As an athlete, you lose sodium in your sweat, so don’t be afraid to make oatmeal tasty by sprinkling on some salt. A quarter teaspoon salt per ½ cup dry oats really helps change the bowl of glue into a yummier breakfast. Add sweetener, if desired, to make the oatmeal taste even better—honey, maple syrup, raisins, chopped dates. These extra carbs offer fuel for your muscles. (part of the content from https://www.acsm.org/blog-detail/acsm-certified-blog/2021/12/15/benefits-of-oats-for-athletes)
Don’t have time to cook oats in the morning? Make overnight oats the night before! Here also some fancy Japanese recipes with oatmeal https://www.oatmeal.co.jp/
In conclusion there’s no age to eat oatmeals, it's good from the youngest to the oldest athletes
My preference before a long training session is a large carbohydrate-rich breakfast (for example large bowl of hot oatmeal with milk and water mixed with 2 teaspoons of honey and nuts). I always try not to delay leaving after eating because if I wait too much I have reactive hypoglycemia.
An interesting way to measure timing and nutrition needs is to use Supersapiens, by monitoring how much glucose is in your blood.
It s a really great technology, but would i recommend it? Yes if you like metrics and already have a balanced diet. In both cases, you’ll still need to invest time and effort into getting the most out of it. You’ll need to test different fueling strategies in training and my advice is to ask a sports nutritionist for advice, because Supersapiens highlights the problem, but it doesn’t give you the solution. That part comes down to trial and error. However, it does provide evidence of what’s happening inside your body, rather than leaving everything purely to guess work. For that reason, if you do sports at a certain level, it’s certainly worth considering. On the other hand, it’s expensive and it’s not for everyone.