Steel-Cut, Rolled or Instant Oats: Which Is the Healthiest?

The oatmeal section at your local grocery store is likely filled with a variety of options: steel-cut oats, rolled oats, instant oats, low-calorie, low-sugar, flavored, plain and so on. Having tons of offerings can seem overwhelming to you, and a healthy food like oatmeal can become something that isn't so healthy once it's overly processed and has tons of sugar added in.

In general, oats are a complex carbohydrate packed with beneficial fiber. "Complex carbs take longer to digest than simple carbs, meaning they keep you full for longer," said Natalie Rizzo, RD, a registered dietitian and the founder of Greenletes. Meredith Price, RD, a plant-based registered dietitian, added that the high fiber content of this whole grain can help lower cholesterol, manage blood sugar, keep the digestive tract healthy and even aid with weight loss. "Oats are also a great source of plant-based protein and iron," Price said.

Oats can be processed into different products. Let's look at the key differences and whether one is healthier than the rest.

What's the Difference Between Steel-Cut, Rolled and Instant Oats?

These three types of oats—steel-cut, rolled and instant oats—start with the same first step. "Oats come from whole groats, and then the outer hull is removed," Rizzo said. The outer hull, also known as the shell, helps protect the seeds. "This leaves the bran, germ and endosperm, which are the nutritious parts of the groat." From here, each product is delivered.

Steel-Cut Oats

Steel-cut oats, also known as Irish oats, come from the first step of the oats process. These are the oat kernels that have had the outer shell removed. Essentially, steel-cut oats are the least processed type, hence taking the longest to cook. "Steel-cut oats aren't rolled or flattened, but they are cut," Rizzo said. "Since they aren't flat, steel-cut oats take a bit longer to cook than rolled oats."

A 1/2 cup (40 grams) of dry steel-cut oats provides:

• Calories: 150
• Protein: 5 grams
• Total Fat: 2.5 grams
• Total Carbohydrates: 27 grams
  • Fiber: 4 grams
  • Sugar: 0 grams

This nutrition information may vary depending on the manufacturer.

Rolled Oats

As mentioned above, the main difference between oat products relies on the manufacturing process, which will impact the texture and cooking time. As opposed to steel-cut oats, rolled oats, known as old-fashioned oats, go through a flattening process. After removing the oat hull, rolled oats are steamed and pressed flat, Rizzo explained. This process gives them a softer texture and reduces their cooking time.

A 1/2 cup (40 grams) of dry rolled oats provides:

• Calories: 150
• Protein: 5 grams
• Total Fat: 2.5 grams
• Total Carbohydrates: 27 grams
  • Fiber: 4 grams
  • Sugar: 0 grams

This nutrition information may vary depending on the manufacturer.

Pictured Recipe: Rhubarb Oat Muffins

Instant Oats

Instant oats come from thinly cutting rolled oats so that they cook quickly, Rizzo explained. Of all three, instant oats, also known as quick oats, are the fastest to make.

A 1/2 cup (40 grams) of dry instant oats provides:

• Calories: 148 grams
• Protein: 5.5 grams
• Total Fat: 2.75 grams
• Total Carbohydrates: 27 grams
  • Fiber: 3.76 grams
  • Sugar: 0.5 grams

This nutrition information may vary depending on the manufacturer.

Which Type of Oatmeal is Healthiest?

As you can see, the nutrition profiles for these three main types of oats are super similar to each other. As far as plain oats go there isn't one kind that's healthier than the other. "It's a common misconception that one type of oat is healthier than another," said Rizzo. "They are all actually identical in terms of their nutrition. The difference is how they are rolled and cut." However, Price added that since instant oats are the most processed option, they generally have salt and added sugars. "This puts them on the lower end of the healthy spectrum, but they're still healthy."

Should You Buy Steel Cut, Rolled or Instant Oats?

The short answer: It depends!

While nutritional profiles are similar across the board, you now know that steel-cut oats take the longest to cook and instant oats—as the name suggests—take the shortest amount of time. Steel-cut oatmeal needs to be cooked over the stove and takes about 10-20 minutes, plus the time it takes to bring a pot of water to a boil. Instant oats can be prepared in the microwave and ready in a minute or two. Old-fashioned oatmeal, however, falls in the middle; you can either prepare it on the stove or microwave and takes around three to five minutes. "If you're someone who struggles with time management in the morning, go for either rolled oats or instant oats that don't have any added flavors or sugars," Price said.

Another thing to consider is texture. Steel-cut oats have a firmer consistency than rolled and instant oats, which have a smoother, creamy-like texture.

With all of this in mind, go forth and enjoy your oats however you please! Rizzo eats them hot or cold as oatmeal or overnight oats. Also, Rizzo uses them as a binder for veggie burgers and a base for energy bites. Price prefers rolled oats for making oatmeal or overnight oats, adding in chia and flax seeds for extra protein and omega-3s, nut butter for more protein and healthy fat and fresh or frozen fruit for more vitamins and antioxidants.