What’s the Difference Between Steel Cut, Rolled & Instant Oats & Does It Matter?

Oatmeal is a powerhouse grain we should all include in our pantries. But with the many varieties of oatmeal on the market, it seems to require a degree in nutrition to figure out which one to buy, especially for the health conscious person. Steel cut, rolled, old fashioned, quick or instant? Are there any real differences that actually matter? The answer: yes, actually but probably not for the reasons you might guess.

Steel vs Rolled vs Quick vs Instant

Oat groats are oat kernels that have had the hulls removed. The hulls are the tough outer shell that protects the seed of the oat plant. Steel-cut, rolled and quick oats all start out as oat groats. Oat groats intended for human consumption are exposed to heat and moisture to make them more shelf-stable. The oat groats are then processed in different ways to create either steel-cut, rolled or quick oats, and instant oats, all of which have distinct characteristics and health benefits.

From Super Healthy Kids

Steel-Cut Oats

Also known as Irish oatmeal, steel-cut oats are most closely related to the original, unprocessed oat groat. To produce steel-cut oats, the groats are chopped into pieces with large steel blades. Steel cut oats have a coarser, chewier texture and nuttier flavor than rolled or quick oats. They also take longer to prepare, with average cooking times varying 15–30 minutes. However, you can soak steel-cut oats beforehand to reduce the cooking time.

Rolled Oats

Rolled oats, or old-fashioned oats, are oat groats that have gone through a steaming and flattening process. They have a milder flavor and softer texture and take much less time to make than steel-cut oats, as they have been partially cooked. A bowl of rolled oats takes 2–5 minutes to prepare. Rolled oats can also be added to goods like cookies, cakes, muffins and bread.

Quick Oats

Quick oats or quick-cooking oats are rolled oats that go through further processing to decrease cooking time. They’re partially cooked by steaming and then rolled even thinner than old-fashioned oats. They cook within a few minutes, have a mild flavor and soft, mushy texture.

Instant Oats

Quick oats are not the same as instant, packaged oats. Instant oats are the most processed and quickest to make, requiring hot water to cook almost instantly. They often contain other ingredients like skim milk powder, sugar, flavoring and other chemical additives.


Oats have many health benefits. These fiber-rich whole grains are a good source of protein and packed with vitamins, minerals and antioxidants. Plus, they are gluten-free, so they make a great choice for those with celiac disease or an intolerance to gluten. While oats are naturally gluten-free, people with celiac disease should choose varieties that are certified gluten-free to avoid those that may have been contaminated with gluten during processing.

Oats are also loaded with beneficial compounds, including antioxidants and beta-glucan, a type of soluble fiber linked to health benefits (3). Eating them may help lower cholesterol, decrease blood sugar levels and help with weight loss.

Due to the increase in processing from steel cut to rolled to quick to instant, the nutritional profiles vary across the plain types but only minimally, usually by a gram or 2 across their carb, protein, fat, fiber and sugar content.

Rolled Oats Steel-Cut Oats Quick Oats
Calories 212 208 208
Carbs 39 g 37 g 38 g
Protein 7 g 9 g 8 g
Fat 4 g 4 g 4 g
Fiber 5 g 6 g 5 g
Sugar 1 g 0 g 1 g

That said, not all oatmeal is created equal.

Avoid Instant Oatmeal & Oatmeal High in Sugar

Despite the overall healthy benefits of oatmeal, you should avoid the two following types for health reasons: oatmeal high in sugar and instant oatmeal.

Oatmeal High In Sugar

No matter what type of oat you choose, it’s always best to choose plain, unsweetened oats. Many packaged varieties have loads of added sugar and additives, making them an unhealthy breakfast choice. For example, one packet (43 grams) of instant maple and brown sugar oatmeal contains 13 grams of sugar (11). This equates to over four teaspoons of sugar. Meanwhile, plain oatmeal contains only 0 to 1 gram.

Too much added sugar can negatively impact your health and lead to a number of conditions, including heart disease, diabetes and obesity (12). For this reason, it’s best to add your own toppings and flavoring to unsweetened oats to keep added sugar to a minimum. Try a tasty combination of fresh berries and healthy fats, such as unsweetened coconut and chopped walnuts.

Instant Oatmeal

You should also avoid instant oatmeal in addition to oatmeal with added sugar since they have a high glycemic index. The glycemic index is a value assigned to foods based on how slowly or how quickly those foods cause increases in blood glucose levels. Also known as “blood sugar,” blood glucose levels above normal are toxic and can cause blindness, kidney failure, or increase cardiovascular risk. Diabetes and pre-diabetes are major consequences of elevated blood glucose levels.

Foods low on the glycemic index (GI) scale tend to release glucose slowly and steadily and can help stabilize blood sugar. Foods high on the glycemic index release glucose rapidly and spike blood sugar. Low GI foods tend to foster weight loss, while foods high on the GI scale can lead to blood sugar regulation issues and weight gain.

Foods are considered low on the glycemic index if they have a GI of 55 or less, moderate at 56 to 69, and high starting at 70.

Steel cut oats and rolled oats have a low GI of 55, quick oats are in the medium impact range at 66, while instant oats clock in on the high range at 79, higher than eating many breads (1):

Porridge, steel cut and rolled oats 55 ± 2
Instant oat porridge 79 ± 3
Porridge, quick oats (2) 66
White wheat bread 75 ± 2
Whole wheat/whole meal bread 74 ± 2

As you can see, while various plain oats may have similar nutritional profiles, they will vary in terms of impact on your blood sugar levels based on their processing amounts, which can have serious health implications, especially your risk of pre-diabetes or diabetes. Steel cut and rolled oats have a low glycemic impact but the more processed quick oats and especially instant oats have much higher glycemic impacts. Additionally, flavored oats usually include added sugar and chemicals that won’t do your body or blood sugar any favors.

Overnight Oats from Chocolate Covered Katie

The Takeaway

Oats are a fiber-rich grain that has been linked to a number of health benefits. Adding more oats to your diet may help keep your heart healthy, weight in check and blood sugar levels stable but only if you eat the less processed versions like steel-cut oats and rolled olds which have the lowest glycemic index and slightly higher fiber content. Quick oats, which have a similar nutritional profile but somewhat higher glycemic index are your next best thing.

However, packaged instant varieties can contain a lot of added sugar and have a high GI at 79, so it’s a good idea to avoid those and choose plain, unsweetened steel or rolled varieties (GI 55) whenever possible, or quick oats (GI 66) in a pinch. Quick and rolled oats take minutes to prepare and won’t spike your blood sugar into the stratosphere like instant oats.

No matter what type of oat you choose, don’t pigeonhole them as a breakfast food. They make an excellent choice at any time of day, including lunch and dinner. Plus, they are a great ingredient to use in cooking. Start experimenting with them today and experience the health benefits they provide over many other foods.

Like this article? Share it so that others can learn these health secrets and start living their best lives now.


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