Diets-Metabolism   [back to the Category]

The purpose of nutrition   [read the french version]

Author :   Dr Paule Nathan

Every living organism has to take nourishment. It is this vital function that enables living things to draw elements, essential for their survival, from their environment. Nutrition provides essential energy.
This energy is then used:
- during relaxation to ensure the main, essential functions of the body; respiration, blood circulation, thermoregulation ensuring a constant body temperature of about 37°, digestion with assimilation and excretion, as well as the good working of organs.
- during cell metabolism with the balance between synthesis and dissipation; these processes being responsible for organ elaboration and dead cell replacement.
- for growth: especially during adolescence and pregnancy.
- during the various physical activities that are undertaken throughout the day. Ballet dancing means increased energy requirements from the earliest age.

Requirements vary according to the individual.
We are not all like machines, based on the same model and consuming the same amount of energy like cars and robots. Thus, energy requirements vary according to the person in question, depending on their physical and calendar ages and their physical activity. Moreover, requirements can be very different for two individuals of the same age and sex with the same occupation. Thus, recommended calorie intake levels can only be given as an indication. And it is the variations in weight gain or loss that gauge whether the energy intake level is too high or too low. We would conclude an excessive intake in the case of a weight gain and an insufficient intake in the case of a weight loss.
Requirements are obviously in line with energy expenditure.

Calories come from the fats (lipids), carbohydrates (glucides) and proteins (protides) which are contained in food.
Energy provided by food is expressed in kilocalories (kcal or Calorie) or in kilo-joules (kJ).
1 gram of protein provides 4 kcalories
1 gram of carbohydrate provides 4 kcalories
1 gram of fat provides 9 kcalories
Food contains varying amounts of carbohydrates, fats and proteins depending on its origin. Thus, every food provides a certain number of calories according to its composition.
Refer to a food composition chart and add it up for yourself; food composition is always given for 100g of the food in question.

Cooked brown rice is:
2.5% proteins which is equal to 2.5 X 4 = 10 Cal
0.6% fats which is equal to 0.6 X 9 = 5.4 Cal
25.2% carbohydrates which is equal to 25.2 X 4 = 100.8 Cal
making a total of 116.2 Calories for one hundred grams of cooked rice
Uncooked brown rice is:
7.4% proteins which is equal to 7.4 X 4 = 29.6 Cal
2.2% fats which is equal to 22 X 9 = 198 Cal
74.6% carbohydrates which is equal to 74.6 X 4 = 298.4 Cal
making a total of 347.8 Calories for 100 grams of uncooked rice.
When referring to the charts be careful to check whether the food is raw or cooked, fresh or dried, desiccated or not. If there is no indication, beware of making a mistake.

Food composition
Man gets his energy from food which is made up of nutriments (carbohydrates, proteins, fats), micro-nutriments (vitamins, minerals, trace elements) and water.
Micro-nutriments and water have no energy value but they are necessary for the good working of the synthesis process and its energy reactions. They are essential for the harmonization of bodily functions and all have a clearly defined role
Food also provides fibre which plays a role in controlling bowel movements. It limits and controls the absorption of carbohydrates and fats.
Food is broken down, during the digestion process that follows a meal, into nutriments, fats, carbohydrates and proteins. Various vitamins, minerals and trace elements are also released. Fibre carries out its action in the digestive tract without being absorbed