The basics of nutrition

Health goes through the plate! We know more and more about the links between nutrition and health. Numerous studies show the impact of nutritional factors on the occurrence of certain diseases and, on the contrary, other studies prove the interest of certain foods, nutrients and behaviors in preventing pathologies. Therefore, nutrition is a key element to maintain and even improve our health level. Through this guide, discover the basics of nutrition with a presentation of essential nutrients, macronutrients (proteins, lipids, carbohydrates), micronutrients (vitamins, minerals, trace elements) and other active compounds (guaranine, curcumin, etc.) found in our food.

What are macronutrients?

The proteins

The protides, often called proteins by abuse of language, are essential to the proper functioning of our metabolism. The protides include proteins, amino acids and peptides : amino acids combined form peptides and the chain of these peptides form proteins. The protides are then macromolecules, formed of one or more polypeptide chains.

There are 20 different amino acids, 12 of which are synthesized by our body and 8 of which are said to be "essential", i.e. they must be provided by the diet because we are not able to synthesize them.

Protein in sufficient quantities helps to maintain and increase muscle mass but also plays a role in maintaining normal bone structure.

For 1 gram of protein consumed, that's 4 Calories provided to the body.


Carbohydrates are our primary source of energy, providing vital fuel for the brain, muscles and some are essential for proper gut function. Commonly called sugars, carbohydrates are made up of hydrogen (H), carbon (C) and oxygen (O), forming the bones. There are two types of carbohydrates, simple carbohydrates such as glucose, lactose and sucrose and complex carbohydrates such as starch, glycogen or fiber.

Just like proteins, for every 1 gram of carbohydrates consumed, that's 4 Calories provided to the body.

Dietary fiber

Dietary fibers are polysaccharides (consisting of several simple sugars, oses) and are part of the family of carbohydrates. There are two classes, soluble fibers such as pectins, which as their name suggests are soluble in water, and insoluble fibers such as cellulose which have a high swelling power. Fibers are not digested by the enzymes of the digestive tract, they will however have benefits on the regulation of intestinal transit, satiety and in the prevention of many diseases.

Fiber provides less energy than simple carbohydrates, only 1.9 kcal per gram of fiber consumed.


Lipids are essential components of our body. They are made up of fatty acids, of which there are two types, unsaturated and saturated fatty acids.

The unsaturated fatty acids (IFAs) are composed of one or more carbon-carbon double bonds (C=C), allowing them to be classified into two categories: monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). The MUFAs have a single double bond, such as oleic acid, an omega 9, while the PUFAs are made up of several carbon-carbon double bonds. Among the latter, we find, for example, omega 3 and 6, which respectively include the following fatty acids, alpha-linolenic acid and linoleic acid, essential fatty acids that must be provided by our diet because humans are not able to synthesize them.

As for saturated fatty acids (SFAs), they have only simple carbon bonds, that is, all carbons are connected to hydrogen atoms.Unsaturated fats are preferred in the diet to saturated fats in order to maintain normal cholesterol levels and more broadly to improve cardiovascular health mainly.

Unlike proteins and carbohydrates, which each provide 4 kcal per gram, fats provide 9 kcal per gram. They thus participate in a consequent way in the coverage of energy needs.

More details on: fats and fatty acids in our diet

To know more

In addition to these macronutrients, only certain organic compounds such as ethanol, polyols and certain acids have an energy value.

What are micronutrients?

The minerals

Minerals are not a source of energy, but are often incorporated into cellular structures and are essential for the activity of hormones and enzymes. They must be provided by the diet because the body cannot manufacture them. There are about twenty minerals with benefits for humans, the main ones are calcium, magnesium, phosphorus, sodium or potassium.

Trace elements

Trace elements are present in small quantities in our body but play a major role in many metabolic reactions. The main trace elements are iron, copper, chromium, selenium, zinc, manganese or iodine.

More details on: minerals, trace elements in our diet


Vitamins are essential substances for the body and in particular for the proper functioning of physiological processes. They are active molecules in very small quantities and their deficiencies can lead to serious illnesses or dysfunctions. The intake of vitamins through the diet is essential since it cannot manufacture them, with the exception of two vitamins K and D. There are 13 families of vitamins divided into two categories:

  • The fat-soluble vitamins capable of dissolving in fat include vitamins A, D, E, and K.
  • The water-soluble vitamins capable of dissolving in water include the B-group vitamins (B1, B2, B3 or PP, B5, B6, B8, B9 and B12) and C.

More details on: vitamins in our diet

What are phytonutrients?

Phytonutrients are nutrientsfrom plants, they occur naturally in plant-based foods such as fruits, vegetables, whole grain products or legumes.

Among the phytonutrients are the phenolic compounds with polyphenols, flavonoids or phenolic acids and carotenoids.

These active compounds are often found in our food and are known to be powerful antioxidants. These nutrients as antioxidants help fight against oxidative stress and impacted diseases such as cardiovascular, degenerative diseases, cancers or premature aging.

More details on: antioxidant power

In addition to their antioxidant properties, phytonutrients can also have health benefits and particularly on the immune or hormonal system for example. They can also act as bacterial or antiviral agents and are responsible for the coloration of some fruits and vegetables such as the orange color of carrots, which is primarily due to beta-carotene.

More details on: phytonutrients in our diet

Learn more about the Recommended Dietary Allowances (RDAs)

The ANCs refer to the benchmarks set by Anses for a large number of nutrients to define the average nutritional requirements of a population. They are updated regularly based on scientific advances. Currently, energy intake is distributed as follows:

  • For a male (18 to 69 years old), the RDA is 2600 Kcal per day.
  • For a woman (18 to 59 years old), the RDA is 2100 Kcal per day.
  • For children depending on age and gender, the RDAs are between 1100 and 2200 Kcal per day.

The Anses recommends composing one's average daily consumption so that the contribution to calories of each major macronutrient group is as follows:

  • 40 to 55% of calories (Kcal) in the form of carbohydrates.
  • 35 to 40% of calories (Kcal) in the form of fat
  • 10 to 20% of calories (Kcal) in the form of protein, whether animal or vegetable
  • 30 g per day of fiber.

The questions we all ask ourselves...

What are the nutritional recommendations of the PNNS?

What is the NSNP?
takes into account the biological, symbolic and social dimensions of the food act and physical activity.
The goals of the NSNP.
  • Reduce obesity and overweight in the population
  • Increase physical activity and decrease sedentary behavior at all ages
  • Improve dietary practices and nutritional intakes, especially among at-risk populations
  • Reduce the prevalence of nutritional diseases
The recommendations on diet, physical activity, and sedentary behavior

To help people make the best food choices and adopt a more active lifestyle, the benchmarks become recommendations and new ones appear!

  • Increase: unsalted nuts, dried vegetables, fruits and vegetables, homemade but also physical activity.
  • Go for: whole grain products, seasonal fruits and vegetables, foods from local producers and, if possible, organic foods, alternating fatty and lean fish, varied vegetable oils, dairy products in a limited way.
  • Reduce: red meat, sweet and salty products, deli meats, alcohol, sitting time, and products with a D and E nutri-score.

What is the difference between Kcal and Calories?

Scientifically speaking, 1 kilocalorie (1,000 calories or 1 kcal) is the amount of heat needed to raise the temperature of 1 kilogram of water by 1°C.

In dietary terms, a single apple provides about 52 kcal or 52,000 calories. Thus, for ease of calculation, energy is expressed in units of 1,000 calories which are also called kilocalories. That is,1 Calorie is equivalent to 1 kilocalorie; the capital "C" in Calories stands for "kcal." Thus, Calories and kilocalories are used interchangeably to express the same thing.

In practice, therefore, it is normal and acceptable to use the lowercase "c" instead of the uppercase "C", especially when speaking.

CNA, RDA, GDA or NRV, what is the difference?

There are several terms used in nutritional recommendations, such as RDAs, RNIs, GDAs and NRVs.

  • ANC : Recommended Dietary Allowances. These are scientific benchmarks for a given population. They represent the sufficient amount of the various nutrients needed to ensure that the nutritional needs of different populations are covered.
  • RDA: Recommended Daily Allowances. These are European regulatory values used as a reference in the nutritional labeling of food products. Unlike the RDAs, the RDAs do not take into account age, gender or lifestyle.
  • DNR: Daily Dietary Reference Points. These are basic values provided by manufacturers, in order to position the energy and macronutrient content of beverages or foods in relation to the RDAs.
  • Nutrient Reference Values. They are a set of nutritional recommendations for different nutrients, such as recommended intakes (RDIs) or average nutrient requirements (ANRs).

Related articles

GUIDE Osteoporosis and diet: which foods should you choose and which should you avoid?

GUIDE Excess uric acid: what foods to avoid and what to choose for gout?

GUIDE Eczema and diet: which foods to avoid and which to choose?

GUIDE Macrocytic anemia: what foods are rich in vitamin B12?

GUIDE Foods rich in vitamin B9 (folic acid) for macrocytic anemia

GUIDE Iron deficiency anemia: which iron-rich foods should you choose?

GUIDE What foods to choose to boost your tan?

GUIDE What are the most effective appetite suppressant foods?

GUIDE Pollen allergy: what foods to choose and avoid?

GUIDE What foods should you avoid or focus on if you have diverticula?

GUIDE What foods should you avoid if you have hiatal hernia?

GUIDE Tendonitis and diet: what foods should you avoid and what foods should you choose?

GUIDE Osteoarthritis and diet: what foods should you avoid and what foods should you choose?

GUIDE What to eat if you are constipated?

GUIDE What to eat while breastfeeding for the health of the child and mom?

GUIDE Prevent and relieve canker sores with food

GUIDE Cellulite and diet: which foods to avoid and which to favor?

GUIDE Prevent and relieve bloating with diet

GUIDE Diarrhea and diet: what foods to choose and what to avoid?

GUIDE Prevent and relieve urinary tract infections (cystitis) with diet

GUIDE What is acid-base balance and how do you restore it?

GUIDE What to eat if you are gluten intolerant?

GUIDE What to eat if you are lactose intolerant?

GUIDE How can you relieve irritable bowel with foods without FODMAPs?

GUIDE How to prevent acne with diet?

GUIDE Preventing and relieving asthma with diet

GUIDE Diverticulitis: Residue-Free Diet

GUIDE What diet should you follow if you have hypothyroidism?

GUIDE How can you prevent muscle cramps through diet?

GUIDE Kidney failure: what foods should you avoid?

GUIDE How can you limit the consequences of hyperthyroidism through diet?

GUIDE What diet to follow for acute pancreatitis?

GUIDE What diet should you follow for chronic pancreatitis?

GUIDE Prevent and relieve hemorrhoids with diet

GUIDE How to get soluble and insoluble fiber in your diet?

GUIDE What is oxidative stress and how can you limit it?

GUIDE What foods to eat to prevent Age-related Macular Degeneration (AMD)?

GUIDE Glycemic index: definition and ranking of foods

GUIDE Preventing and relieving gastritis with food