Carbohydrates, saccharides, simple sugars, sugars, carbohydrates, as many names as biochemical structures or roles for the body. Indeed, carbohydrates represent a very important nutrient because they are an immediate source of energy. What do we need? What does the glycemic index mean? Everything you need to know about carbohydrates can be found in this article.
What is a carbohydrate?
A carbohydrate is an organic molecule. As such, it is composed of carbon, oxygen and hydrogen. This whole is more or less complex and soluble in water. Carbohydrates can be divided into two categories that reflect their composition.
On the one hand simple carbohydrates, long called fast sugars. In chemistry, they are monosaccharides, composed of a single molecule (glucose, fructose, galactose), or disaccharides composed of two molecules (lactose, saccharose, maltose).
On the other hand are complex carbohydrates, long called slow sugars. In chemistry, they are polysaccharides. They can be digestible like starch or non-digestible like cellulose, which represent dietary fibre. These molecules are in fact glucose polymers, i.e. a chain of glucose molecules attached to each other with different bonds.
What are the foods that are rich in carbohydrates?
Carbohydrates are found in many foods. They are mostly found in foods of plant origin, very little in foods of animal origin except for milk, which is a source of lactose.
Again, foods can be divided into two categories.
Foods rich in complex carbohydrates:
- cereals (wheat, rice, rye, oats, buckwheat) and derived products (flours, breads, biscuits)
- tubers (potatoes, sweet potatoes, yams)
- legumes (lentils, chickpeas, kidney beans, flageolets)
- starchy fruits (chestnuts and chestnuts)
Foods rich in simple carbohydrates:
- fruits and vegetables
- dairy products
- sweet products (ice cream, chocolate, cakes, biscuits, pastries)
What are our needs in carbohydrate?
Carbohydrates are the basis of our diet. Indeed, they should cover 40 to 55% of our energy needs. They are a vital fuel for the body and release 4 kcal per gram. For example, a sugar cube weighs 5g, it provides 100% carbohydrates, i.e. 5g, so it provides 20 kcal.
In practice, complex carbohydrates should make up two thirds of our diet and the rest should me made up of simple carbohydrates. Sugar consumption should not exceed 100g per day (excluding lactose). Not forgetting fibre, which should be provided at a level of 30g per day.
Are carbohydrates good for your health?
The answer is yes, because as we have just seen, the main function of carbohydrates is to provide energy. The body uses carbohydrates in the form of glucose. In fact, all the carbohydrates we ingest are transformed into monosaccharides, or glucose, during digestion. This allows the carbohydrates to pass into the bloodstream. Other monosaccharides that are assimilated, such as fructose, are then transformed into glucose by the liver.
What are the roles of carbohydrates?
After passing into the bloodstream, glucose is distributed in the body to be used by all cells (muscles, heart…) but especially nerve cells and red blood cells. Indeed, these specific cells are characterized as glucodependent because glucose is their only source of energy. It is important to know that the brain uses on average 120g of glucose per day.
Furthermore, carbohydrates have a structural role because they are part of the composition of all our cells and those of many molecules (cell walls, membrane receptors, DNA, etc.).
When the body has excess glucose, it is converted to glycogen and stored in the liver and muscles. The glycogen then constitutes an energy reserve that can be used immediately. As a result, carbohydrates have a nitrogen-saving role, because glycogen stocks prevent the muscles from using their own proteins to provide energy.
As for fibres, since they are not assimilated, they do not provide energy. However, they have many roles:
- they stimulate transit and increase stool volume
- they bring and maintain satiety (length of time without hunger between two food intakes). Fibre is therefore an ally in weight loss.
- they have a preventive role on colon cancer.
- They help balance the intestinal flora and strengthen the immune system.
What are the carbohydrates to avoid?
Some carbohydrates are to be avoided because they provide no or very few essential micronutrients to the body such as vitamins and minerals. The foods concerned are industrial and highly processed foods:
- sandwich loaves, industrial baguettes, Viennese buns, burger buns…
- Viennese pastries, pastries
- cookies, cakes
- sodas, fruit juices, sweetened drinks
- industrial pizzas
- ready meals
These foods have often had sugar and/or gluten added that is not nutritionally interesting and can even lead to health problems. Be careful, this does not mean that everyone can be lactose intolerant, but some people have a genetic predisposition and a greater sensitivity than others which leads them to reduce these products.
On the other hand, limiting does not mean deleting. Eating pleasure is important and an integral part of our daily lives. It is important to know that frustration will hurt you more than pleasure from time to time.
What are the right carbohydrates to lose weight?
When you want to start losing weight, it can be interesting to slightly reduce your carbohydrate intake to let the body draw from its reserves. But the most important thing is to monitor the quality of these carbohydrates. Halving your carbohydrates and eating only white pasta will be much less effective than not reducing carbohydrates at all but varying your intake with wholemeal rice, sourdough bread and coral lentil pasta for example. The right choice of products is then essential. Care must be taken to vary the sources of carbohydrates.
Another concept is also important in weight loss: the glycemic index. Carbohydrates are classified according to their glycemic index, i.e. according to their hyperglycemic effects (ability to increase blood sugar levels after ingestion). In fact, while all carbohydrates are sources of glucose, they do not all raise blood sugar levels in the same way. Overall, simple carbohydrates often tend to raise blood glucose levels quickly, while for complex carbohydrates this can vary.
There are three kinds of glycemic indexes: the low GI is below 55, the medium GI is between 55 and 70, and the high GI is above 70. The higher a food’s glycemic index, the more quickly and abruptly it raises blood sugar levels (glycemia).
Creating a spike in blood glucose leads to a spike in insulin, out of which this hormone triggers the storage process. Repeated spikes in blood sugar levels can therefore cause weight gain.
In general, whole grains, fresh fruits and vegetables, legumes, and oilseeds have a low to medium GI. These are therefore the products to be favoured.
Once again, balancing your diet while enjoying your meal is key. It is by pleasing yourself that you take care of yourself!
Article written by Romane, Dietician at Foodvisor.