Porridge is notorious for being a healthy breakfast, particularly on cold winter mornings. But are all oats made the same? In this dietitian’s guide we break down the main types of oats, from oat groats to instant sachets, and explain what really matters when you are choosing which to buy.

Written by Tatiana Bedikian, Accredited Practising Dietitian and owner of Body Fusion.

Are Oats Healthy?

NEW short section near the top to capture the high-volume “are oats healthy” query and frame the article. Keep it general and qualified. Link a credible source such as the Grains & Legumes Nutrition Council (glnc.org.au) or the Heart Foundation for the wholegrain and beta-glucan points.

In general, oats are a nutritious wholegrain. They provide slow-release carbohydrate for energy, along with fibre, including a soluble fibre called beta-glucan. As part of a balanced diet, wholegrains like oats are associated with heart health and healthy digestion. How processed the oats are, and what is added to them, makes a difference to how filling and how blood-sugar-friendly your bowl will be, which is what this guide covers.

The Main Types of Oats

Oat groats

All oat grains begin as groats, which are simply hulled, toasted oat grains. They are not commonly available except in some health food shops. Normal cooking time is 20 to 25 minutes, similar to other wholegrains like buckwheat or barley. If you have the time to find and cook them they are the least processed of the oat products, but they are not necessary for a hearty, healthy breakfast.

Steel Cut Oats

Steel cut oats have made a resurgence in the marketplace thanks to health trends and bloggers. In fact, they have long been eaten in Scotland and are known as Scottish or Irish oats. Steel cut oats are produced when the groat is cut into small, thick pieces. They taste nuttier and have a gritty texture. Cooking time is around 15 to 20 minutes once added to boiling water.

Rolled Oats

Instead of being cut into chunks, oat groats are flattened, rolled out and then steamed. This processing means they cook faster, in around 5 to 10 minutes once added to boiling water. Rolled oats (sometimes called traditional or old-fashioned oats) are the everyday all-rounder for porridge, bircher and baking.

Quick Oats

Quick oats are the most heavily advertised and, from what we see with clients, the most commonly used. They are more processed than rolled oats because they have been cut into smaller pieces, rolled for longer and partially cooked, which reduces their cooking time to about 1.5 minutes in the microwave.

Instant and Flavoured Oats

Another step down the processing line are instant oats. They are cut even finer than quick oats, partially cooked, and often have skim milk powder, emulsifiers and other additives included to create a creamy texture when cooked. Flavoured sachets usually have added sugar, which is worth checking on the ingredients list.

Steel Cut vs Rolled Oats: Is One Healthier?

This is where the debate gets a little heated. Steel cut oats are often argued to be far superior to rolled oats, but in reality there is very little difference between the two. Energy, carbohydrate, fibre and glycaemic index are all pretty similar.

As you can see there are a few SLIGHT differences, however nothing that will drastically make a difference to your health. Energy, carbohydrates, fibre, GI are pretty much identical.  Because of this interest in health foods, most brands now sell a steel cut range. They are perfectly nutritious, but tend to cost noticeably more than everyday rolled oats. Home-brand rolled oats are often several times cheaper than a branded steel cut product for a similar pack size, so plain rolled oats are a great value, healthy option.

The original quoted 2015 Woolworths prices ($5.99 steel cut vs $0.99 rolled, note the original ‘0.99c’ typo). Prices are now well out of date, so the copy above generalises. If you would like to keep a concrete price comparison, refresh it with current Woolworths or Coles prices and cite the date checked.

Quick and Instant Oats vs Steel Cut and Rolled Oats

The bigger difference is not steel cut vs rolled, it is how heavily processed the oats are. Compared with steel cut and rolled oats, quick and instant oats tend to have:

A higher glycaemic index (GI)

A higher GI means a faster release of sugar (from the carbohydrate and any added flavours) into your bloodstream. That gives a quicker burst of energy in the morning and a larger insulin response, which may be less ideal for people managing insulin resistance or diabetes, and the oats take less work for your body to break down.

Lower fibre

Because of the extra processing, some of the fibre that wholegrain oats naturally contain is reduced. The machinery has done some of the mechanical work your digestive system was designed to do. Generally this means quick and instant oats are less filling, so you may feel hungry again an hour or two after breakfast.

More added sugars (in flavoured varieties)

Added sugars are a significant contributor to energy intake and one of the bigger nutritional challenges we face as a population. Flavoured sachets have extra sugar added. A useful rule of thumb is to avoid products with sugar listed in the top three ingredients. In many flavoured quick or instant oats, sugar is the second ingredient. Regularly eating sweet-tasting breakfasts can also train your taste buds to keep seeking out sweet foods.

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The Verdict

Choose traditional rolled oats, and if time and budget allow, feel free to splash out on steel cut oats. Focus on the quality of the product rather than just the numbers on the side of the packet. Watch out for added sugars, especially in gourmet packets with added flavouring and dried fruit.

The simplest approach is to buy good old-fashioned rolled oats (like your grandma would have) and add your own flavour from naturally sweet, fibre-rich fruit and vegetables such as banana, pear, apple, berries or even grated carrot, with a sprinkle of cinnamon, some crushed nuts and, if you like, a teaspoon of raw honey or 100% maple syrup.