Carbohydrates – an energy source for the body

Carbohydrates are the main source of energy for our bodies. They are made up of sugar molecules, which are broken down by the small intestine. Carbohydrates should account for around 45 to 55 per cent of our daily calorie intake.

01.03.2021 Lara Brunner 6 minutes

Carbohydrates consist of carbon, hydrogen and oxygen. They are made up of chains of sugar molecules, which vary in length. They are mainly found in plant-based foods. Carbohydrates are a source of energy – the fuel for our muscles and brain. The body transports them to all our cells via the bloodstream. Carbohydrates provide 4 kilocalories per gram. 

Types of carbohydrates

In chemistry, carbohydrates are divided into four types, which contain different numbers of sugar components:

  • Monosaccharides consist of just one sugar molecule. For that reason, they are also called simple sugars. Examples of this type include fructose and glucose. They are mainly found in fruit. They are also added to many processed foods such as soft drinks, cakes, biscuits and dairy products.
  • Disaccharides are also known as double sugar because they consist of two sugar molecules. Examples of this type include sucrose (table sugar) and lactose. Sucrose is mainly found in sweets, while lactose is found in milk and dairy products.
  • Oligosaccharides are carbohydrates consisting of three to nine sugar molecules. These complex sugars are found in pulses, for example.
  • Polysaccharides are made up of ten or more sugar components, hence the prefix “poly”, meaning “many”. Examples of this type of carbohydrate are starch and dietary fibre. They are found in plant-based and cereal products, for example.

Simple carbohydrates: absorbed quickly

Mono- and disaccharides enter the bloodstream quickly and increase the release of insulin. This causes our blood sugar level to drop quickly, which, in turn, can trigger food cravings. However, foods with simple carbohydrates, such as fruit, are important because they contain vitamins and other valuable nutrients.

Complex carbohydrates: keeping you full for longer

Carbohydrates consisting of three or more monosaccharide molecules have to be broken down by the body first before they can be digested. After that, they enter the bloodstream slowly and evenly. This means they keep you full for longer and do not cause insulin levels to spike. They provide the body with valuable fibre. Complex carbohydrates are mainly found in cereal products, pulses and vegetables.

What are carbs?

The terms “carbs” and “carb-loading” are widely used, especially in the field of sports nutrition. “Carbs” is simply short for “carbohydrates”. Endurance athletes often eat large amounts of carbohydrates before competing in major events in order to improve their performance. This practice is known as “carb-loading” or “carbo-loading”.

The most important carbohydrates for humans


Glucose, also known as dextrose, is only found in its free state in small amounts. It is contained in fruit and honey, for example. Glucose is often linked with other carbohydrates such as sucrose or lactose. The small intestine absorbs the glucose and transports it to the body cells. The glucose then supplies the cells with energy. Glucose is actually the only source of energy for the brain and red blood cells.


Fruit and honey naturally contain fructose. However, fructose is also added to soft drinks and yoghurt to sweeten them. When consumed in large amounts, it can sometimes cause flatulence and diarrhoea. The intestine can only absorb a limited amount of fructose.


Lactose is only found in breast milk and the milk of mammals. In the small intestine, an enzyme called lactase breaks down lactose into glucose and galactose. When someone is lactose intolerant, they don’t have enough lactase in their small intestine, or any whatsoever, meaning they are unable to break down lactose. This causes problems such as flatulence, stomach aches or diarrhoea.

Lactose intolerance: what you need to know


Dietary fibre is also simply called “fibre”. The human body cannot digest it. That is to say, the small intestine cannot break it down and absorb it. It is broken down by intestinal bacteria. Fibre leaves you feeling more full and has a positive impact on blood sugar and insulin levels because it delays the absorption of nutrients in the small intestine. It also supports the gut flora and reduces the levels of lipids and cholesterol in the blood. The recommended daily fibre intake for adults is 30 g. Some good sources of fibre are wheat bran, flax seeds and chia seeds, white beans, soy meat, lentils and peas.

Good to know

Sweeteners such as saccharin or aspartame are not carbohydrates. They are much sweeter than sucrose, but they provide little to no energy. They do not affect our blood sugar levels. Sugar substitutes such as sorbitol or xylitol, on the other hand, are carbohydrates. They are about as sweet as sucrose, but don’t have as much of an effect on blood sugar levels. You can use both sweeteners and sugar substitutes if you want to give up sugar. However, this won’t stop sugar cravings!

It’s important to have a balanced diet

The body converts excess carbohydrates into fat and stores it in the liver, muscles and fatty tissue. The Federal Food Safety and Veterinary Office (FSVO) and Swiss Society for Nutrition (SSN) therefore recommend that around 45 to 55 per cent of our daily calorie intake comes from carbohydrates. No more than 10 per cent of our energy should come from added sugar.

How sensible is a low-carb diet?

Do you have questions about your diet?

Our Health Consultation advisors will show you how to achieve a balanced and nutritious diet.

An example: 45 to 55 per cent of a daily intake of 2,000 calories would equate to 225 to 275 g of carbohydrates. No more than 50 g of these carbohydrates should come from added sugar.

There are 100 g of carbohydrates in:

  • 150 g pasta (uncooked)
  • 180 g Bircher muesli
  • 500 ml soft drink

There are 10 g of added sugar in:

  • 100 ml soft drink
  • 100 g flavoured or fruit yoghurt
  • 50 g ice pop

Recommended sources of carbohydrates include cereals and cereal products (preferably whole grains), potatoes, fruit, vegetables and pulses. Food and drinks with added sugar should only be consumed occasionally. Examples of low-carbohydrate foods include fish, meat, dairy products, eggs, tofu and green vegetables.

Even these foods contain hidden sugar

The glycaemic index tells us how quickly the blood sugar level rises after consuming carbohydrate-rich foods. The lower the GI value, the healthier the food. Meals will normally have a low GI if:

  • they contain minimally processed foods,
  • they have been freshly cooked and not heated up,
  • they contain complex carbohydrates (e.g. products with whole grain and fibre),
  • they do not consist purely of simple carbohydrates, but also of fat and protein.

However, the GI does not tell us how much carbohydrate food contains, meaning it cannot always be applied in practice.

The glycaemic load not only takes into account the type of carbohydrate, but also the food’s carbohydrate content. An example: Carrots have a similar GI to white bread. But their GL is significantly lower, as they have a lower carbohydrate content.

  • Carrots have a GI of 70. There are 50 g of carbohydrates in 700 g of carrots. Carrots therefore have a GL of 5.
  • White bread has a GI of 70. There are 50 g of carbohydrates in 100 g of white bread. White bread therefore has a GL of 35.

If we look at the content and type of the carbohydrate as well as its effect on blood sugar, we can see that carrots are the healthier option. 

GI and GL values can provide some guidance when figuring out which carbohydrate-rich foods are suitable and which are not. However, these are not the only criteria for judging food. For example, they don’t tell us anything about low-carbohydrate foods. Just make sure you’re regularly eating foods with a low GI and a low GL. These include wholegrain bread, muesli without sugar, pulses and vegetables. This is in line with the general recommendations for a balanced diet.

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