Diet for diabetes

What are carbohydrates and why are they important?

In this article we would like to provide you with useful information about carbohydrates so that you can use this knowledge in your everyday life.

However, this does not mean that you have to avoid carbohydrates. You still need them, but must consume them in a clever way.

In this article I would like to share important information about various types of carbohydrates and to give you some advice on how to incorporate them into your meals.

What are carbohydrates and why do we need them?

Carbohydrates are macromolecules whose primary function is to provide our bodies with energy. They make up 45-55 % of our nutritional needs. In the case of an average adult woman, whose daily need is about 2000 kcal, it means ca. 225-275 g of carbohydrates a day.

Simple carbohydrates

Or sugars, as we usually call them. We can list saccharose, fructose, glucose and lactose here for example. These elements consist of one or two molecules at most. They get into the bloodstream very quickly, so they will increase your blood glucose level if you consume them solely.

The odd one out here is fructose, because it raises blood glucose level slowly and the glycemic index of fructose is only 24, which counts as very low compared to glucose (GI=100).

Which simple carbohydrate should I have?

It is recommended to always have some grape-sugar (glucose) on you. In the case of hypoglycemia, it is the best way to quickly raise your blood sugar level.

Regarding its low glycemic index and high sweetening values, fructose is a suitable sweetener for people who live with diabetes. But consuming too much of it as a sweetener can have adverse effects on our bodies. E.g. It can raise our triglyceride levels and uric acid levels. The recommended quantity is appr. 30 g per day from added fructose. So, we advise that you mix up your sweeteners, and use other ones as well instead of/next to fructose.

According to several nutrition-related studies, added sugar should not make up more than 5-10% of our daily carbohydrate needs; this means 1-3 spoonfuls of sugar in the case of 2000 kcal per day.

Are you interested in the newest sweeteners? Then please read our post about the different type of sweeteners and their affect on IBS and IBD.

Complex carbohydrates

These are the carbohydrates that consist of three or more sugar molecules. Their structure has a lot of variation, which highly influences their digestibility.

Potatoes, rice, pasta – what do they have in common?

Did you know that the carbohydrate content of these foods is made up by starches? Starches are one of the most common complex carbohydrates. They make up the glucose storage in plants and consist of connections of simple sugar molecules. If the bonds between these molecules are ripped apart by our digestive enzymes, then their nutritional content will be changed into glucose, which will lead to blood glucose level elevation.

Legumes, cereals and pseudo-cereals contain a lot of starches, so it is recommended to eat them only with foods high in fibre, protein or fat (e.g. cabbage, roast meat) in order to slow down their absorption.

Did you know that the proportion of amylose and amylopectin, which gives the structure of starches, has an important effect on their elevating impact on blood sugar level? Foods with a higher proportional rate of amylose are digested slower. So, they may raise your blood glucose level slower. Durum wheat and basmati rice are such examples. If you are curious of the glycemic indexes of different carbohydrate rich foods just download DiabTrend. When you log your meals it will automatically show you the foods GI if it's available.

Are fibres also carbohydrates?

Beside starches, fibres also consist of sugar molecules, but with bonds that cannot be ripped apart by the digestive enzymes, meaning that they reach the colon undigested. However, the bacteria living in the colon are able to digest these fibres and change them into short chain fatty acids (SCFA). A part of them is able to be absorbed, so they can provide us with energy. As a result, fibres contain only 2 kcal/g of energy.

However, this does not mean that they raise our blood glucose level. Various vegetable fibres have a good effect on our BGL, slowing down or prohibiting the absorption of some nutrients, playing an efficient role in establishing a stable blood glucose level.

We can divide fibres into three main categories: soluble fibres (chia seeds, oatmeal), non-soluble fibres (wheat bran, apple peel) and resistant starches (green banana, cold cooked rice, cold cooked potatoes). They help to balance our blood glucose level, and have a good effect on our blood fat values. They feed the gut flora and increase the motility of the bowels. So, when enough water is consumed they also lower the risk of constipation. It is highly recommended to consume fibre-rich food every day. The min. recommended quantity of fibre is 25 g per day.

From sugars to fibres

As you can see, there are many different types of carbohydrates which are very similar to each other, but all of them have a different biological effect. If you are interested in carbohydrates, and you are eager to read more about them, just follow our blog!


  • Advanced Nutrition and Human Metabolism, 6th edition
  • Krause’s Food and Nutrition Therapy, 12th and 14th edition
  • Ádám Veronika - Orvosi biokémia
Koszecz Anna
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September 1, 2021

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