Dietetics is the science of balanced diet. If nutrition is defined as the science which examines the relationship between food and health, including diet includes a cultural dimension related to dietary practices.
Nutrition is the science that studies the food and their effects on human beings, while the diet is the study of the set of rules that should govern the power of the human being.
Dietetics is a “social norm” that varies over time, according to civilizations, as religions or beliefs and of course depending on the state of knowledge in nutrition.
In our time, as a result of scientific development, the two concepts tend to join. The “standard diet” is based on scientific knowledge that continue to grow.
Dietetics is the most natural way to maintain or regain weight, maintain or improve their health.
The history of the evolution of diet shows that there is not a diet but diets, which depend on the design of the human digestion and knowledge of food.
Until the development of chemistry, dietary old Europe, India and China, had large commonalities: digestion is cooking; the body is composed of elements that determine a character;
it is recommended to eat a balanced diet, that is to say food corresponding to his character.
For the Hippocratic dietetics, there are 4 elements: Water, Earth, Air, Fire, which correspond to four temperaments: lymphatic, melancholic, sanguine and choleric. Each food is classified as hot, cold, wet or dry.
For Ayurvedic nutrition, there are 5 elements: Ether, Air, Water, Fire, Earth, which correspond to three temperaments: Vata, Pitta, Kapha. Each food is classified according to the elements, or doshas temperaments, 6 flavors and 3 categories or Gunas (Sattvic, Rajasic or Tamasic).
For the Chinese diet, there are 5 elements: Wood, Fire, Earth, Metal, Water, which correspond to the same five temperaments. Foods are classified by flavor, color, consistency. Food can also be yin or yang.
The Hippocratic dietetics and Chinese diet survived the advances in medicine and chemistry, while the Ayurvedic diet has survived in India (Unani Tibbi medecine). Naturopathy has taken some concepts of Ayurveda.
Scientific dietetics in the West has changed its definition of digestion: all mechanical and biochemical processes that transform and absorption of food. It has changed the classification of food, now composed of nutrients directly assimilated proteins, lipids, carbohydrates, vitamins, minerals, trace elements.
Dietetics official retains the concept of balanced diet to stay healthy.
Protesters of the official dietary created in the twentieth century, several dietary alternatives, which take both dietary theories and ancient scientific knowledge of foods: naturopathy, vegetarian movement, Catherine Kousmine method. Diets, more or less scientific, more or less commercial, have also diversified.
The diet has in recent years a greater extent including the increase in diseases related to the “bad food”.
The general principles of Western scientific dietetics are:
1 – Energy: quantitative need
It is generally believed that the energy requirement depends on the climate, age, size and activity of the subject.
However, a single study has found a paradoxical result: Researchers at the University of Leeds in Britain have estimated in 1997 that there was no link between the number of calories burned during exercise and number of calories consumed during the meal. They submitted eight volunteers in a program of intensive gymnastics. Result: they ate as much during exercise days than inactive days.
2 – Energy: qualitative distribution source
Foods contain many nutrients. Some of these nutrients (carbohydrates, lipids, proteins) are also sources of energy. To be called a balanced menu, you must know its energy needs and properly allocate energy between the different sources. It should also provide other non-energy nutrients (vitamins, minerals, fiber and water) in sufficient quantity.
Energy intake of key nutrients is calculated by various estimates, such as the method of indirect calorimetry. We obtain:
- 1 gram of carbohydrates provides 4 kilocalories (kcal), soit17 kilojoules (kJ);
- 1 gram of fat provides 9 kcal or 38 kJ;
- 1 gram of protein provides 4 kcal or 17 kJ;
The theoretical distribution of the energy provided by food in France is as follows:
- 50-55% carbohydrates (carbs focusing on low glycemic index);
- 35-40% lipids (part of plant origin: for example, virgin olive oil);
- 12-15% protein (part of plant).
Are called “empty calories” the calories found in foods (such as soft drinks, sweets or alcohol) that bring a lot of energy with very little non-energy compounds such as essential fiber, minerals and micronutriments
3 – Other nutrients
Other elements of nutrition play an important role, including:
dietary fiber, vitamins, macro-minerals: calcium (Ca), phosphorus (P), potassium (K), chlorine (Cl), sodium (Na), magnesium (Mg).
the trace minerals: iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), iodine (I), molybdenum (Mo), etc..
In addition, the current science ignores in labeling, polyphenols, phytosterols and the richness of the plant world in molecules which we have yet to discover the full potential.
4 – Excess of certain nutrients and health
Excessive consumption of certain nutrients can be dangerous. For example, sodium in Western countries. Consumption is mainly in the form of sodium chloride (table salt). Overconsumption of sodium is the origin of the water retention in the bloodstream which leads to hypertension.
Ensure that everyone knows be balanced menus is a public health issue. It is now clear that dietary imbalances are a major source of diseases such as cardiovascular disease, obesity, eye diseases, diabetes, osteoporosis and certain cancers.
The diet studies have shown that virtually all local cuisines of the world de facto apply these principles. For example,
Couscous combines starches (carbohydrates), fiber (four vegetables), meat (fat and protein) and is often accompanied by sour milk (calcium).
English breakfast, which may include eggs, fried bacon, fried potatoes, sausages, etc.. is very rich in lipids, but complements a diet that was once traditionally based of slurry in the day.
We must make a distinction between food consumed by humans for 7 million years until the Neolithic (and still consumed by the last hunter-gatherers) and that consumed since the Neolithic. Until the Neolithic, diet consists mainly of fresh fruits and nuts, vegetables, tubers (but not potatoes), meat and fish. There was no dairy, no grains, no legumes, no salt, sugar or oil. Of course, given the difficulty in obtaining meat, food was probably more carbohydrate. On the other hand, our ancestors ate in the largest amount possible nuts that were the parallel (even better) with our modern oils. With the use of fire and cooking food for the consumption of carbohydrates (tubers, cereals, pulses), life expectancy has increased while.