Nutrition is the study of nutrients. There are two categories of nutrients: macronutrients and micronutrients. Macronutrients are made up of proteins, fats and carbohydrates while micronutrients are made up of vitamins and minerals. Let’s take a closer look at the role of macronutrients.

PROTEINS

What are their roles?
Foodvisor protéines animales oeufs

Proteins play a number of important roles in the body and are therefore vital for us, humans. One of their functions is to create and maintain our muscles. Nonetheless, they are not limited to one function: proteins allow the immune system to function properly, are part of the composition of cells and allow the transport of molecules such as oxygen in the blood thanks to haemoglobin. Under certain circumstances, proteins can be used as energy for the body. This is because the body is able to convert a protein (set of amino acids) into glucose. This is called gluconeogenesis. On the calorie level, 1 gram of protein provides 4 kcal. The recommended dietary allowance in protein is between 10% and 20% of the total daily energy intake.

What are they made of?

A protein consists of amino acids linked together by peptide bonds. It can be visualised as a necklace of pearls: a pearl represents an amino acid and when they are put together, they form a necklace (a protein). In humans there are 8 essential amino acids, that is to say our body cannot synthesize them and therefore their intake through food is essential. 

Animal or vegetable proteins?

There are two sources of protein: vegetable and animal. Animal proteins are of very good quality and animal products (meat, fish, eggs, milk,…) provide all the essential amino acids necessary for our body. On the other hand, most of the time, proteins of vegetable origin present a limiting factor (lack of an amino acids), they are said to be of lower quality because the “necklace” is not complete. However, it is possible to supplement this limiting factor with other foods of plant origin, this is called protein complementarity. It is often a matter of combining a cereal with a legume. For example, corn and kidney beans are complementary and the mixture of these two foods provides the body with a number of proteins that are needed. There is one exception to this rule: soybeans. Soy contains complete proteins, very similar to animal proteins. 

CARBOHYDRATES

Foodvisor glucides pain farineWhat are their roles?

This macronutrient is composed of molecules that are digestible (carbohydrates) and molecules that are not digestible by the body (fibers). Carbohydrates are also known as “sugars”. Carbohydrate NCAs are between 40 and 55% of the total daily energy intake, they represent the largest source of energy for the body. Therefore, the main role of carbohydrates is to provide us with immediate energy, we can consider carbohydrates as our main source of fuel.

Additionally, carbohydrates are indispensable to the organism because they intervene in the healing mechanism, enter into the constitution of cell membranes and allow us to save up on our protein reserves. When the body needs energy, it draws on its glucose reserves (glycogen from the liver and muscles), if these reserves are not sufficient, then the body is forced to use existing proteins, and this can reduce muscle mass over the long term or decrease the effectiveness of ones immune system. 

Fibers, on the other hand, are a molecule that are not digested by the intestine because the body does not have the enzymes to do so. Enzymes are molecules that act like scissors, they come to cut the different nutrients. Each enzyme (or scissors) has a specific shape to the molecule it wants to reduce. On the other hand, their roles are numerous and fibers are particularly used in order to regulate transit. Moreover, since they are not digested, they do not provide energy, therefore no calories

What are they made of?

Unlike fibers, carbohydrates are digested by the body and provide 4 kcal per gram consumed. This nutrient is divided into two categories, simple carbohydrates and complex carbohydrates. They are also known as simple sugars and slow sugars, respectively. They are easy to recognize sinc in chemistry, sugars are called “oses“: saccharose, glucose, lactose, … An exception remains: starch, a complex carbohydrate contained in starchy foods. 

Simple carbohydrates are monosaccharides or disaccharides, that is to say molecules composed of one or two bones (small molecules composed of a single carbon chain). For example, glucose, fructose and galactose are monosaccharides and lactose, sucrose and maltose are disaccharides.

Complex carbohydrates have a more developed structure, they are called polysaccharides, which are large molecules made up of many bones. Amylopectin and amylose are two starch-forming polysaccharides.

Carbohydrates can be found in many foods such as fruits and vegetables, cereal-based products, legumes, sweet products and some dairy products.

LIPIDS

What are their roles?

Lipids are an integral part of our diet because they allow the construction of our neurons (saturated fatty acids), the digestion of our lipids (cholesterol in bile salts), the production of part of our hormones, the regulation of our body’s temperature, improved vision (vitamin A), the fixation of calcium on our bones (vitamin D), and the reduction of inflammation (omega 3). Lipids provide 9 calories per gram consumed, so you have to choose your sources carefully and consume lipids in adequate quantities.

What are they made of?Foodvisor lipides matières grasses noix

Contrary to preconceived ideas, lipids are not to be banished from our diet as they represent 35% to 40% of the total daily energy intake of a healthy adult. Lipids are made up of fatty acids. There are different types, each with different properties. Fatty acids can either be saturated or unsaturated, the difference can be observed at the molecular level. Saturated fatty acids are mostly found in animal products and unsaturated fatty acids are often found in plant-based products. 

As you can see, it is important to balance your meals by eating foods that correspond to the different macronutrient categories. None should be set aside, only the quantities of each should be be modified according to your needs or objectives .

 

 

 

Article written by Romane Guerot, dietician at Foodvisor