Instant Oatmeal Vs Steel Cut Oatmeal: Your Body Knows The Difference… But Do You?

Breakfast is an important meal because, for many people, it ends up being one of the most nutrient dense meals of the day.

It also happens to be a where many of us eat foods we might not otherwise eat at other times of the day.

Oatmeal, which is an extremely popular breakfast choice, is one such food.

It’s lauded as a nutrient dense whole grain packed with a soluble fibre known as beta-glucan which helps with blood cholesterol  regulation.

Oatmeal, however, also happens to come in a variety of shapes and sizes and not all of them are  made equal.

That’s what today’s article is all about.

And no, I’m not referring to the difference between plain and unsweetened instant oatmeal.

If a food is truly good for you, adding 5 grams of sugar ( 20 calories) does not make it bad for you.

Instead, the focus of today’s discussion centers around the the differences between Instant And Steel Cut oatmeal, which are really quite different from each other.

By the end of today’s article you will understand why the the more widely available instant oatmeal is actually not as great for you as  steel cut oatmeal and also be in a position to decide whether or not that is something you should be concerned about.

So what’s the difference?

Steel Cut and Instant oatmeal are on opposite ends of the oatmeal processing spectrum.

On the one hand, Steel Cut oats are the closest thing you can find to oats in their original form.

The original oat kernel is cut once or twice with a steel blade to create them ( also known as Irish Oats).

They take 25-30 minutes to cook, which may deter some people from purchasing them.

They also tend not to be as visible or well represented on grocery store shelves.

On the other hand, instant oatmeal is essentially the most heavily processed version of oatmeal ( excluding oat flour I suppose?) , requiring as little as 60 seconds to cook.

There are a number of varieties of instant oatmeal available and they tend to be very visible on grocery store shelves.

They cook so quickly as a result of an extensive process of cutting, pre-cooking, steaming and flattening.

There are a variety of other types of oatmeal that are available as well and these varieties essentially fall somewhere in between steel cut and instant oatmeal in terms of level of processing and cooking time.

Is there a difference in nutritional value between the two?

Despite going through a much more significant processing procedure, instant oats retain most of their original nutritional value.

The calorie, fibre and vitamin/mineral values remain very similar between steel cut and instant oatmeal.

This is essentially why instant oatmeal, despite significant processing, can still be referred to as a whole grain.

So why did I even bother writing today’s article?

Your appliances aren’t the only things that notice the difference in the type of oatmeal you select.

Your body does too, even if on the surface different types of oatmeal may appear nutritionally similar.

The one critical difference between Steel Cut and Instant Oatmeal is how rapidly they are broken down and  absorbed into your bloodstream ( and how much/how quickly they raise your blood sugar as a result).

This phenomenon is measured using the glycemic index.

Steel Cut oatmeal has a low glycemic index score because it is digested and absorbed slowly and does not raise your blood sugar quickly nor very high.

Conversely, instant oatmeal has a high glycemic index score ( similar to white bread ) because it is absorbed quickly and raises your blood sugar rapidly and to higher levels.

The amount of each food you eat also has a role to play ( known as glycemic load) but for the sake of today’s article I will carry out the discussion assuming all things are equal quantity wise.

So is that enough of a reason to drop your instant oats for steel cut?

What Does Science Say About Glycemic Index?

First of all, you should know that there was a period of time several years ago when Health Canada actually considered putting the Glycemic Index ( GI) values on food labels.

Ultimately, Health Canada chose not to at that time for a variety of reasons, one of them being that although GI is useful, there is much more to a food than JUST its glycemic index score.

BUT,   GI labelling exists in countries such as Australia ( see example below from 2011) and I’ve heard rumblings that Diabetes Canada ( where I was formerly employed) is making a second push to convince Health Canada to bring GI labelling here at home.

And I don’t think it’s the worst idea, as long as it’s done correctly.

Here’s why:

When I looked at some of the best available evidence on the connection between dietary choices, glycemic index and health outcomes, I generally found that people who had diets including more lower glycemic index foods had a reduced risk of chronic disease across a broad spectrum of categories including:

Type 2 Diabetes/ Blood Sugar Control

Additional evidence

Diabetes Canada 2018 Practice Guidelines:

Replacing high-glycemic-index carbohydrates with low-glycemic-index carbohydrates in mixed meals has a clinically significant benefit for glycemic control in people with type 1 and type 2 diabetes.

Heart Disease

Blood Pressure

Colon/Bladder Cancer

Overweight/Weight Loss

Additional evidence I

Additional evidence II

Now, among some of the other foods that have a high glycemic index ( ie: white bread, pure glucose), instant oatmeal is surely a superior selection.

It’s safe to say , however, that instant oatmeal is not quite at the level of steel cut oatmeal when it comes to overall healthfulness.

And there is something else to consider as well:

In  a 2014 Journal of the American Medical Association study, researchers found that when someone’s overall dietary pattern is quite strong, going out of your way to choose lower glycemic index foods does not offer benefits to risk factors such as insulin sensitivity, blood pressure and blood cholesterol. ( which are all risk factors for chronic disease).

In other words, if you have a GREAT diet, it might not matter whether you choose instant or steel cut oatmeal for breakfast.

So what is the take home message then?

Take Home Message

Glycemic index ( owing to physical/mechanical processing) is the defining attribute separating instant and steel cut oatmeal.

Glycemic index matters, which is why the high glycemic index score of instant oatmeal is not necessarily ideal.

When all else is equal, it generally makes sense to choose the food with a lower glycemic index.

It’s also why GI labelling may make its way to Canada in the years to come, and why it is already in Australia.

With that being said, glycemic index is not the be all and end all.

If you eat a very strong diet and choose instant oatmeal out of convenience, it’s unlikely to have any great negative consequences on your health.

If, however, your choice of instant oatmeal is your daily diet’s “saving grace” and what you consider to be one of your best choices throughout the day, you’d make a great candidate to make the switch over to steel cut oats.

Hope this helped!

Until next time,

Andy De Santis RD MPH