Calories, the term is known, used by all ... especially when it comes to losing weight. But what are we talking about? What is it exactly?
Calorie is a unit of measure of energy contained in a certain amount of food (usually 100 grams). Originally, the calorie is a physical unit of measure: it is the amount needed to raise the temperature of one gram of water by 1 ° C. In dietetics, the energy value of a food corresponds to the amount of heat released by its combustion.
In France, the kilocalorie (Kcal), which equals 1000 calories, is used as a unit; the international unit is the kilojoule (Kjoule), knowing that 1 kcal = 4.18 kjoules.
> 1 gram of carbohydrate brings 4 kilocalories,
> 1 gram of protein brings 4 kilocalories,
> 1 gram of fat provides 9 kilocalories.
To function, our body needs calories that it will then spend. In each person, this energy expenditure is mainly divided into 3 levels:
> The basic metabolism: it is the energy used by the body, at rest, for its functioning (breathing, functioning of organs and cells). The basic metabolism represents 60 to 70% of our energy expenditure.
> Food thermogenesis: this is the energy spent on digestion, intestinal absorption, food storage. It represents only 10% of the total energy expenditure.
> Physical activity: this is energy used for travel, household activities, work, sports ... Physical activity accounts for between 20 and 30% of our caloric expenditure. It is here that we can act to better balance our energy balance.
Some figures on our calories spent:
- 1 hour of sleep or rest: 60 kcal.
- 1 hour of activity in sitting position (TV, computer, reading, transport ...): 90 kcal.
- 1 hour of activity while standing (toilet, dressing, housework ...): 120 kcal.
- 1 hour of gymnastics, gardening, walking: 170 kcal.
- 1 hour of sport activity (ski, tennis, bike ...) or professional intense: more than 300 kcal.