Now several methods to estimate the calories we burn more or less reliable, they are essential to understand your needs to estimate an unnecessary calories.
Above all, we must know that our weight is a balance between inputs and energy outputs: if we eat more calories than we expend.
What does energy expenditure?
But what do we exactly by energy expenditure? They are composed of three factors:
The resting energy expenditure (also called basal metabolism). This is the minimum expenditure necessary for our body to operate the bodies at rest. It corresponds to 2/3 of the energy expenditure for 24 h.
The thermic effect of food. This is the energy required for food processing (to build muscle, for example). This corresponds to 10% of total expenditure over 24 hours.
Expenses related to physical activity. It represents a small percentage, but it is very variable from one individual to another.
Uneven meet expenses
Several factors explain the changes in energy expenditure among individuals:
Weight: more we weigh heavier, our body consumes energy. It’s almost good news if you have a lot of overweight: You burn more calories through physical activity!
Age: the older you get, the less calorie expenditure.
Gender: a man spends a lot more calories than women, even if they have the same weight.
How to evaluate this expense?
To evaluate the energy consumed, we can make in vivo measurements, but they are quite stringent. For example, to measure the basal metabolism, we can put the person in a bell and measure gas exchange: oxygen consumption is directly linked to calories burned.
But as it is impossible to submit everyone has this treatment, there are different methods of assessment.
To calculate the basic metabolism: To evaluate the basic metabolism of the body, that is to say the energy expenditure at rest, there are different formulas based on age, weight, height and sex. The most widely used and the oldest and the formula of Harris and Benedict (1919). Recently (1996), another formula was developed, that of Black, theoretically more accurate. But the problem is that it applies mainly to a western population. In both cases, these equations often slightly overstate the actual BMR.
Equations of Harris and Benedict
– Men: Basal Metabolic Rate (Kcal) = 66.5 + + 13,8xPoids 5xSize – 6,8xAge
– Women: Basal Metabolic Rate (Kcal) = 655 + + 9,6xPoids 1,9xSize – 4,7xAge
With the weight in kg, height in centimeters and age in years.
– Men: Basal Metabolic Rate (Kcal) = 1.083 x 0.48 x Weight Size 0.5 x 0.13 x 1000 Age / 4.1868
– Women: Basal Metabolic Rate (Kcal) = 1.083 x 0.48 x Weight Size 0.5 x 0.13 x 889 Age / 4.1868
With the weight in kg, height in meters and the age in years.
To calculate the total expenditure: To calculate the total cost must be added to the basic metabolism of energy corresponding to physical activity. For this, include two methods: one based on the activity, the other based on the level of personal activity (NAP PAL or English).
The method of NAP of burning calories will assign a multiplier to the basic metabolism, corresponding to different activities of the day. Simply assess the distribution of occupations of a person to know his expense.