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What Are Refined Carbohydrates?

Updated: May 31, 2021

I was asked this recently and thought it was a great question. Even for those who know what carbohydrates are, they may know how to distinguish refined or processed carbs from healthier, complex carbohydrates and how to pick the ones better for their health.

Let's explore what refined carbohydrates are

  • What do they contain (sugar) or not (fibre, nutrients)

  • How do they impact our body (blood sugar, insulin, fat storage)

  • Where do we find them (usually in packaged food)

  • How do you avoid them (eat fresh and minimally processed food grown from a plant)

Not all carbs are bad

Before we move on, please make a note - not all carbs are bad, carbs are not created equal. Plenty of carbohydrate-rich foods are packed with vitamins, minerals and fibre, including fresh fruits, vegetables, nuts and seeds, and whole grains.

What are refined carbs?

Refined carbohydrates are found in highly processed and packaged foods like white flour, white bread and pastries, pies and desserts. These are usually highly palatable, convenient foods that contain little or no fibre or nutrients except for the calorie content from sugar or starch. Starches are long chains of sugar molecules, which are easily broken down into simple sugars like glucose, by enzymes (amylase) in our saliva and intestines.

Whole vs refined grain

In grains such as wheat, rye and barley, nutrients like vitamins, minerals and fibres are found in the bran and germ. These nutrients are removed along with the bran and germ during processing, leaving a highly refined powder or flour void of nutrients but full of calories. As mentioned earlier, flour and starches are refined carbohydrates that can be digested easily into simple sugars, which can then spike our blood sugar and insulin levels. Having too much sugar in our blood for a prolonged period of time can seriously affect our insulin sensitivity and increase the risk of diabetes and heart disease.

Glycemic Index (GI)

I can't talk about refined carbs without mentioning GI. Glycemic index measures how quickly a food increases our blood sugar levels on a scale of 0-100. Glucose, a simple sugar, has a GI of 100. Foods with lower GI tend to help with weight loss, whereas foods with higher GI >70 can help to provide quick release of sugar to support intense activities like long distance running.

Whether you are diabetic or prediabetic or have no issues with insulin sensitivity, I would still recommend focusing on lower GI foods to avoid blood sugar or insulin spikes. Maintaining a relatively stable blood sugar level means that we don't go hungry or hangry every two hours, and risk disrupting our productivity with snacks or overfeeding. Spiking your insulin levels constantly is a sure way to put on weight and encourage fat storage instead of fat burning.

Source: Atkinson, F., Foster-Powell, K. and Brand-Miller, J.C., International tables of glycemic index and glycemic load values: 2008,  Diabetes Care, 31 (12), 2281-2283

Brown vs White Bread

So what are the foods with the highest GI? Is brown bread much better than white bread in terms of the impact on our blood sugar levels? How about breakfast cereals? Whole fruits versus fruit juices?

Without looking at the table, guess which of the following has the highest GI? What are you having for breakfast tomorrow?

  • Banana

  • Instant oat porridge

  • Sweet potato, boiled

  • White Bread

Why is high blood sugar or insulin bad for us?

Insulin is a hormone responsible for regulating our blood sugar level and fat storage. Without going into the details, it is important to remember that if we consistently eat too much sugar and processed carbohydrates, our body may end up with too much insulin and inflammation, which can affect our health, through weight gain, more fat storage and increase the risk of obesity and diabetes.

I need to get back onto refined carbs, but if you want to geek out more about sugar and insulin, see a few book recommendations at the end of the blog or read my old blog on sugar and its impact.

Where do we encounter refined carbohydrates?

They are commonly found in white bread, pasta, pastries, pies, potato fries, pizzas, bagels, biscuits, crackers, cookies, cereals, cakes, snack bars, energy bars, jam, low-fat yoghurt, frozen yoghurt, soft drinks and pretty much anything that says low fat. Anything that says low fat is basically a disguise for high sugar.

Refined or processed carbohydrates-rich food will likely fit into the following:

  • Came from a factory

  • Dry, convenient and fast to eat

  • Highly palatable but insatiable

  • Has a nutrition label

  • Has an expiry date

  • Long list of ingredients

  • Ingredient list starts with wheat or sugar

  • Has 10 or more ingredients

  • Contains preservatives, additives, colourings, letters and numbers

  • Low fat

  • White or beige

  • Health claims such as heart healthy, calcium rich, fibre rich, reinforced vitamins or minerals

  • Prominently displayed in supermarkets, including freshly baked pastries and cookies

How do you avoid refined carbs?

Very Simple. Eat Real Food.

The best way to avoid refined carbohydrates is to eat plenty of single-ingredient food. Ideally it's something you get from a fresh food market or directly from a farm supplier. Whole fruits like apples, bananas, melons and avocados don't have nutrition labels or expiry dates. Vegetables like broccoli, kale, sweet potatoes, cabbages and butternut squash are good examples too. A chicken egg or a piece of fish is considered whole, real food, more so than any low-fat protein bar you can see in a health food store.

Characteristics of unprocessed whole foods

  • Single ingredient

  • No packaging except for the skin on the fruit or vegetables

  • No preservatives, additives, colourings

  • Need washing, peeling and or cutting

  • No nutrition label

  • No expiry date

  • Not made in a factory

  • Grown from the ground or picked from a tree or plant

  • Colourful

  • Will likely rot away in less than a week

What about whole grains?

Whole grains are complex and healthier carbs than refined, as long as they are real whole grains with bran and germ attached, that’s where the nutrients and fibre sit. If you enjoy oatmeal porridge, choose steel-cut oatmeal (less processed) instead of instant oatmeal (very processed). Ancient grains like amaranth, millet, teff, farro, rye, barley, and quinoa (seeds) are great sources of fibre, vitamins and minerals.

Antinutrients - Low in Bioavailability

However, I'd like to add that I am not a full supporter of grains because of antinutrients. Have you heard of phytic acid or enzyme inhibitors? These are the plant's defensive mechanism to protect their seeds/ offspring. Plants don't really want humans or animals eat up all the seeds which are their babies. Phytic acids are one of their defenses, they bind to minerals like zinc and iron, making it harder for our body to absorb, which means the nutrients from seeds and grains are unavailable for humans, i.e. low in bioavailability.


I am not a nutritionist but as a runner and health coach this topic sits close to my everyday life. If you are reading this, I am sure you care about your health and I also want the best for your health. What kind of changes would you like to make today? Is there something in your breakfast or lunch that you can replace with a whole food? It can be something simple like having an omelette with an avocado to replace your daily instant oatmeal.

Let me hear your feedback if this makes sense. If you'd like to make some changes to your lifestyle and nutrition, please reach out or sign up for a free consultation.

Or download a self guided health-coaching e-guide for FREE.

Further information

International Tables of Glycemic Index and Glycemic Load Values: 2008, Atkinson, F., Foster-Powell, K. and Brand-Miller, J.C., (2008), Diabetes Care, 31 (12), 2281-2283

Glycemic Index for 60+ Foods

Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease

Dr. Robert H Lustig

The Case Against Sugar

Gary Taubes

Why We Get Fat

Gary Taubes

Grain Brain: The Surprising Truth about Wheat, Carbs, and Sugar--Your Brain's Silent Killers

David Permutter

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