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The complete guide to carbohydrates.

The complete guide to carbohydrates.

Nutrients. 17.04.2019

Macronutrients are essential for the proper functioning of our body. They are also our main source of energy. Yet, despite this being the case, they are often wrongly considered to be the main source of weight gain. So, what are carbohydrates, where do we find them and what is their role?

Carbohydrates: Roles and food sources

Carbohydrates, often referred to as sugars, play a crucial role in ensuring that our body works as it should. They are differentiated by their structure and the effects that they have on the body.

There are two types of carbohydrate: simple and complex. They are assimilated by the body thanks to digestive enzymes, unlike fiber, which is considered a non-assimilable carbohydrate.

Simple carbohydrates.

Simple carbohydrates may consist of a subunit (monosaccharide) or two subunits (disaccharide).


Fructose is mainly found in fruits, vegetables and honey. It is an excellent sweetener and has a low glycemic index. As a result, it does not induce insulin peaks and therefore does not lead to fatigue.

Glucose is naturally present in honey, in some fruits (grapes), and is most often found in industrial products in the form of syrup. The glycemic index of glucose is 100, so it can cause a large increase in blood sugar levels.


Sucrose is a natural sugar extracted from sugar beet or sugar cane and is used to make the white sugar that we’re all familiar with. White sugar, when consumed moderately, is not bad for your health.

Isomaltulose is naturally present in honey and sugar cane. It can be produced industrially through the fermentation of sucrose. Its structure means that it is digested slowly by our body which in turn means that it has a low glycemic index.

Complex carbohydrates.

Unlike simple carbohydrates, complex carbohydrates consist of more than two subunits.

Complex carbohydrates are found in the form of starch in cereals, tubers or vegetables. These foods are grouped under the category of « starchy foods ».

Maltodextrin is a complex carbohydrate that exists through the partial transformation of starch. Its glycemic index is variable according to its refinement rate. The more maltodextrin is industrially modified, the higher this index will be.

The high protein and fiber content within Feed. meals ensures that the overall glycemic index of our recipes does not induce significant peaks in blood sugar levels.

Assimilable carbohydrates represent an average of 40-45% of the average total energy intake per day. This is lower than the 40-55% that is recommended by ANSES.

These results can be explained through the overconsumption of foods that are rich in lipids and proteins at the expense of food sources that are rich in carbohydrates such as bread, tubers and cereal-based products.

Did you know?

Did you know?

The GI measures the ability of a carbohydrate or a food to increase the level of glucose in the blood. The average glucose level is between 0.7-1.1g per litre. The higher the GI of a particular food, the quicker it will increase the level of glucose in the blood. The presence of fiber, protein and fat in your meals reduces the impact of the glycemic index of your food by slowing down the distribution and absorption of carbohydrates. If the food has a low GI, the glucose from digestion is released more slowly into the body. This means that there is no peak in blood sugar levels and that it is distributed over a sustained period of time, ensuring long-lasting satiety.  

What are their roles in our body?

Carbohydrates have two primary jobs: an energetic and structural role.

  • Energy role: Glucose is the first source of energy used by cells. A single gram of carbohydrates provides 4kcal.

Some cells, often referred to as “glucose dependent cells”, such as red blood cells and neurons, can only use glucose as a source of energy.

The brain receives a daily carbohydrate energy supply of roughly around 150g. The rest is distributed between the muscles and other organs.

  • Structural role: Carbohydrates are used in the composition process of cells but also different bodily tissues such as cartilage, mucus and skin.

Simple carbohydrates are mainly found in fruits, vegetables and sugar.   

Amount of simple carbohydrates per 100 grams.

Granulated sugar 100 gr
Honey 81,3 gr
Agave 70,2 gr
Banana 19,6 gr
Grape 15,7 gr
Apple 11,6 gr
Beetroot 9 gr
Courgette 6,5 gr
Tomato 2,6 gr

Complex carbohydrates come from cereals (oats, rice, corn, etc…), tubers (potatoes, cassava), pulses (dry peas, lentils, etc…) and starchy fruits such as walnuts.

Amount of complex carbohydrates per 100 grams.

Rice 78 gr
Corn 72 gr
Oat 60 gr
White bread 50 gr
Walnut 23 gr
Potato 15 gr
Pea 15 gr
Lentil 15 gr

For an average adult, ANSES recommends that carbohydrates make up 40-55% of the total energy intake. They recommend that ⅔ of these are complex and the remaining ⅓ simple carbohydrates.

For health reasons, sugary and sweets products should not exceed 10% of the total energy intake.

Someone who has a daily energy requirement of around 2000kcal should consume between 200-275g of carbohydrates per day. The sugar intake should never exceed 90g.

In Europe, we tend to prefer simple carbohydrates over complex. This ultimately leads to a negative impact on our health.

Complex carbohydrates are digested and therefore assimilated gradually by the body. Consequently, they prevent spikes in the blood sugar level and lead to energy being released over a sustained period of time.

Whereas simple carbohydrates cause a rise in blood sugar levels which results in insulin being secreted which ultimately leads to the pancreas being overworked. The daily overconsumption of carbohydrates is one of the primary triggers for diabetes.

Even for those who are intent on losing weight, it is strongly recommended not to too drastically reduce the consumption of carbohydrates. Carbohydrates should constitute at least 40% of the daily energy consumption and they are vitally important in ensuring that the glucose-reducing cells are able to operate effectively. They also play a crucial role in the cerebral function.

If this ratio is not respected then the body will have to find a different source of energy, usually via the transformation of fats into energy molecules. Although this process is physically possible, the resulting molecules, ketone bodies, are toxic.

The special case for dietary fiber.

Fibers are non-assimilable carbohydrates that are not broken down by digestive enzymes. Nevertheless, they nourish the bacteria of the intestinal flora and are therefore essential for the proper functioning of the digestive system.

There are two types of fiber, soluble and insoluble.

Soluble fiber has the ability to absorb water and slow down distribution, while insoluble fiber has the opposite effect.

To sum up

To sum up

There are two families of carbohydrates: assimilable and non-assimilable carbohydrates.

There are two types of assimilable carbohydrates: simple and complex carbohydrates.

Dietary fiber can be found within the non-assimilable carbohydrate family.

Carbohydrates contribute to the body’s energy and structure. They are a vital component in a healthy diet.

ANSES recommends that carbohydrates make up between 40-55% of the  total daily energy intake.