What’s the difference between refined and complex carbohydrates?

With the conflicting advice out there about whether they’re good for us or not, carbs can seem complicated.

However, there is a simple reason for the fact that people seem to either love or hate carbs. There are actually two different types of carbohydrates, each with different properties.

What are carbohydrates?

Before getting into the two main categories of carbohydrates, remember that when we talk about carbohydrates, we could be referring to three separate sub-types – sugar, starch and fibre.

Thereafter, carbs fall into two broad categories – ‘refined’ carbohydrates (which consists of the carbohydrate sub-type sugar), and ‘complex’ carbohydrates (which consists of the carbohydrate sub-types starch and fibre).

What are refined carbs?

Refined carbohydrates, also known as ‘simple’ carbs, refer to sugars (e.g. glucose, fructose, sucrose) or anything made from grains which have had the fibrous wheat germ and bran removed.

Grains which have been refined also lose most of their vitamins and minerals in the process.

All refined carbohydrates are made up of short chains of molecules, which are rapidly and easily converted to glucose in your body, causing a sudden blood sugar raise, or ‘spike’, soon after eating. This causes your body to produce lots of insulin to allow the glucose to enter your body’s cells to be used as energy.

Insulin is vital in helping your body convert food into energy, but if you are experiencing several blood sugar spikes throughout each day, your body can over-produce insulin, leading to insulin resistance. Insulin resistance is when your body’s cells no longer recognise insulin and is a contributory factor to developing type 2 diabetes.

Regular consumption of refined carbs can also lead to weight gain. This is due to a number of factors – mainly that refined carbs leave you hungrier and more prone to snacking and overeating.

Also, the low fibre content in most refined carbs means you won’t get the benefits of a high-fibre diet such as reduced sugar cravings, feeling of satiety and happier gut bacteria.

Nutritionists generally advise avoiding refined carbs as much as possible, leaving them for an occasional treat rather than being consumed at every meal.

Refined carbohydrates include:

• Sugar-sweetened foods such as cakes, biscuits, sweets and pastries
• Fizzy drinks and some fruit juices and smoothies.
• White pasta and white bread
• White rice
• Sweetened breakfast cereals, cereal bars and energy bars.

What are complex carbohydrates?

Complex, or ‘good’ carbs, are in many ways the opposite of their refined counterparts. Incorporating starchy and fibrous foods, complex carbs are loved by nutritionists for their health-boosting properties.

Complex carbs are made of longer chains of molecules than refined carbs. As a result, they are digested more slowly and aren’t broken down into glucose as rapidly by your body. This provides your body with longer-lasting energy as opposed to the blood sugar spike followed by a ‘crash’ which can leave you feeling weak, hungry and dizzy.

Further, whereas refined carbs from grains have been stripped of their nutrients in the refining process, complex carbs retain them. As a result, complex carbs from grains boast a variety of nutrients including vitamin B1, vitamin B6, magnesium, phosphorus, selenium and manganese.

Complex carbs include:

• Wholegrain bread and pasta
• Brown rice
• Grains such as quinoa and freekeh
• Most fruits and vegetables
• Legumes such as lentils and beans

Is this related to the glycemic index (GI)?

You may have heard of the glycemic index (GI) in relation to carbohydrates. The GI is a ranking system for carbohydrates based on how quickly the body converts them into glucose.

The GI ranges from 0 – 100 according to how much the food raises the blood sugar after you’ve eaten it, with 100 being equivalent to pure glucose. Foods that have a high GI are quickly broken down and turned into glucose by your body, which leads to a spike in your blood sugar level. These are usually (but not always) refined carbohydrates, with low GI foods converting into glucose slower. These are normally complex carbohydrates.

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Last updated: 31 March 2020

Sources

https://www.diabetes.co.uk/insulin-resistance.html

https://www.nhs.uk/live-well/eat-well/the-eatwell-guide/ https://www.nhs.uk/live-well/healthy-weight/why-we-need-to-eat-carbs/ https://www.nhs.uk/live-well/eat-well/starchy-foods-and-carbohydrates/