The word diet refers to the way we eat, but also to what we eat.
The term nutrition has several different meanings. Strictly speaking, the word nutrition designates the science that studies the action of food on our metabolism (all chemical reactions inside our body) once it went through our digestive system in order to be transformed in nutrients. It corresponds to the process of transformation and of using the food by the body. In order for these functions to be fully efficient, to maintain you in good health and without weight excess, you need to privilege a balanced diet.
The nutrition functions correspond to all functions insuring the supply in substances and energy of the body as well as its maintenance and renewal. These functions must be maintained even in the case of specific diets. Thus, they insure the longevity of the individual. These functions call in, in a coordinated manner, the four body systems that are the following:
- the digestive system (swallowing food, transformation of digestible nutrients and waste evacuation through stool);
- the respiratory system (oxygen supply as energy for chemical reactions);
- the circulatory system (in particular, the transport of oxygen and nutrients by the blood);
- the excretory system (removal of waste and toxins through the urine).
The food that we swallow (meat, eggs, fish, fruits, vegetables, legumes, cereals, dairy products, drinks) contains nutrients (that we commonly call proteins, sugars, fats, vitamins, minerals, fibers, etc.) that our body will extract, transform and dispatch towards each internal recipient (organs, muscles, brain, skin, etc.) according to its needs.
The organic and energy molecules – contained in these foods and that we also call macronutrients – are not digestible as such by our body. Digestion transforms them in elementary molecules, nutrients that become digestible by our body. They are: proteins, animal or vegetable, provide amino acids (20 different amino acids exist) that form the structure of all cells, tissues and organs. Carbohydrates or “sugars” mainly provide glucose, but also fructose from fruits and galactose from milk. The glucose is the main energy nutrient of our cells. Lipids or “fats”, animal or vegetable, provide fatty acids (saturated, monounsaturated and polyunsaturated), some of which are called “essential” because the body is not able to produce them (for example, Omega-3, Omega-6, Omega-9). Fatty acids have either a role of energy reserve (triglycerides), either a role as a component of our cell membranes, giving them “elasticity”.
Thus, the stomach provides to the small intestine nutrients (or micronutrients) that are directly digestible: amino acids, fatty acids, minerals, vitamins, fibers and phytoelements.
To stay in good health, our body needs more than 40 different nutrients. Some of them are necessary in large quantities, macronutrients. Proteins, lipids and carbohydrates are part of this category. Micronutrients (vitamins, minerals and trace elements) are necessary in smaller quantities.
Vitamins are associated with the idea of reconstruction of the cells’ shape. They are vital to the growth and the maintenance of the body. Each one of the 13 known vitamins has a specific role.
In what concerns mineral salts, they are classified in two very different groups:
- Dietary elements (the necessary quantity for the body is relatively important): we can include here calcium, magnesium, potassium, sodium as well as chlorine, phosphorus and sulphur (no deficiency was noticed for these last 3 elements).
- Trace elements, unstable compounds present in very small quantities in the body. Nonetheless, even in small quantities, they act as catalysts (activating and accelerating) in the countless chemical reactions in our body. They include metals such as iron, zinc, copper, manganese, chromium, cobalt, molybdenum and metalloids such as fluorine, iodine, selenium, silicon, bromine and boron. We are still discovering others, without being able to explain their exact role.
Being informed about food and knowing how to read food labels are part of the basics for all those that are interested in dietetics and their diet.
A good diet will often allow to replace too many useless diets and will represent an important support to maintaining yourself in good health.
The notion of a balanced diet rests on variety, moderation and conviviality and leads to well-being and health for each individual. Eating balanced meals is good for your health. It allows you to feel good while maintaining a good functioning of the body, to avoid all signs of tiredness dues to a lack of vitamins and minerals, to have a healthy digestive system without suffering of digestive disorders and to prevent certain diseases like diabetes, cardiovascular diseases, cancers, hypercholesterolemia, high blood pressure, while slowing down aging due to deficiencies. Key factor in the prevention of numerous pathologies, the importance of a balanced diet increases with passing years. One must keep in mind that the nutritional needs are different according to age, gender, height, weight, physical activity and psychological state (pregnancy, breast feeding) or even pathological (diseases).
Eating well means adopting a varied and balanced diet, that is eating everything in adapted quantities. Nutrients, minerals and vitamins are provided by food. Nonetheless, the consumption of a single type of food does not allow to cover all organism needs. Each food group has its role in our daily dishes. All of them are essential in order to reach a nutritional balance, but some of them must be consumed moderately. It’s about favoring food that can benefit our health (fruit, vegetables, starches, fish) and to limit the consumption of sweet (candy, sweet drinks), salted (crackers, chips) and fat (cooked pork meats, butter, cream) products. That is why there is neither prohibited, nor miracle food and that is why a balanced diet is built during several days, sometimes even weeks.
It is recommended to eat 3 real meals a day, and if possible to have a snack around 4 – 5 PM. Generally speaking, you need to try to eat at breakfast a quarter of the daily food intake. At lunch, avoid eating heavy which will lead to a decrease in vigilance during the digestion. Snacks must be light, containing fast-acting sugars (fruit, chocolate, sweet drink). Preferably dinner should also be light. Indeed, the calories stored during the evening meal and not used during your sleep will be stored as fat. The food intake must be divided harmoniously during the day. The food should be sufficient in quantity, but not excessive.
In order to be balanced, the diet must contain different nutrients: lipids, carbohydrates and proteins, but also to have a sufficient intake of vitamins and trace elements.
We can distinguish 7 food groups that provide more or less lipids, carbohydrates and proteins.
1. Group “Meat, Fish, Egg” contains animal proteins, iron and vitamins, in particular vitamins B. There is almost the same protein quantity in 100 grams of meat as in 100 grams of fish or 2 slices of ham or 2 eggs. It is recommended to vary protein sources in order to enjoy all the benefits of each one of them.
2. Group “Milk and dairy products” provide animal proteins, calcium and vitamin A in the fat ones, vitamin B. They are rich in fat and thus must be consumed moderately. We can eat them every day while diversifying the dairy produce.
3. Group “Cereals and starches” consists in slow carbohydrates (containing starch), plant proteins, fibers that help digestion, vitamin B. We can eat them every day in all meals.
4. Group “Fruit and vegetables” contains minerals, vitamin C, plant proteins and fibers. The fruit and vegetables the richest in vitamins are the most colorful ones, ripe and of course fresh. It is recommended to eat at least 5 portions of vegetables and/or fruits a day.
5. Group “Fatty substance” (butter, margarine, oil) contains lipids, vitamins A, D and E. Lipids are sources of essential fatty acids, which means that our body cannot make them. These fatty acids are necessary for the body because they are constituents of the cellular membranes and must necessarily be brought by food. Their consumption must be limited.
6. Group “Sweet products and alcoholic drinks” are fast-acting sugars that have a sweet taste and that provide immediate energy”. They are essential to health, but they can induce the notion of pleasure and conviviality. There are forbidden or in very little quantity in diabetics.
7. Water is the only indispensable drink.