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How to know the daily calories you need?
Some of the most common questions among those people or athletes who want to take care of their diet are:
How many calories do I need every day? What does it depend on? What if I want to gain muscle mass? What do I want to lose fat? Are there risks assuming excessive caloric deficits?
Well, to be able to respond to it, the first thing is to make a series of calculations depending on the characteristics of the person, the type of training that performs or amount of daily physical activity And finally the aim That has been marked, well maintenance of body weight, increased body mass or loss of fat.
What are calories?
The first thing is to define the unit to measure energy, either ingested through food or the spent through physical activity or different metabolic processes.
For this, Kilocaloria (Kcal) is used, which can be defined as:
"Quantity of heat needed to raise the temperature of a Kg of water of 15ºa 16º, at sea level"
You can also use another unit of measure, which is kilojulio (kJ). This corresponds to 0.24 kcal, or a Kcal at 4,184 kJ.
How to calculate energy expenditure?
The energy expenditure of a person is the total amount of energy that consumes over a day.
Since every day is different and the type of activities or training is different, energy expenditure for each day will be different.
This will depend on some involuntary factors such as resting energy expenditure or the thermal effect of food and other voluntary factors such as energy expenditure due to physical exercise.
The components of total energy expenditure are:
- Basal energy expenditure: Energy used to maintain vital functions.
- Thermal effect of food: Energy used for food digestion.
- Energy Expenditure Physical Activity: Energy consumed depending on the type of physical activity and/or training. It depends on the duration and intensity of training.
Total energy expenditure is the sum of all components, which can be estimated as follows.
Basal Energy Expenditure (GEB)
There are two formulas to calculate daily calories and, above all, for the calculation of basal energy expenditure.
The first one is to use predictive equations depending on gender, height and age. The most common is Harris & Benedict:
- Basal energy expenditure on women: 655 + (9.6 x weight [kg]) + (1.85 x height [cm]) - (4.7 x age)
- Basal Energy Expenditure on Men: 65.47 + (13.7 x weight [kg]) + (5 x height [cm]) - (6.8 x age)
The second option, and much more precise, would be Perform a study of the metabolic rhythm at rest with a gas analyzer.
This would be done in fasting conditions, just awakened by the person and lying down. During a minimum period of 10 minutes (ideal 20) its consumption of oxygen and CO2 production is evaluated through the equipment software used.
Thermal effect of food (EA)
This value is estimated, and is considered around 8 -10% of resting energy expenditure, previously calculated
PHYSICAL ACTIVITY ENERGY (AF)
In this case there are equally two options.
The first of them is to multiply by a coefficient the energy expenditure at rest, depending on the level of activity of the person.
The coefficients would be the following:
- Women: 1.46 (sedentary) / 1.64 (active) / 1.82 (athlete)
- Men: 1.55 (sedentary) / 1.78 (active) / 2.1 (athlete)
Given the subjective character of this measure, There is an alternative such as registration and calculation of caloric expenditure through electronic devices such as smart watches, activity bracelets or smart rings.
In the applications of the devices, both daily caloric expenditure and the caloric spending of a specific training can be counted, which is dependent on its intensity and duration.
Total Energy Expenditure (GET)
To calculate the total energy expenditure, There are three options:
-
Using only equations:
Kcal / Day: (Geb x Af) + EA -
Measuring the GEB and AF with devices and estimating the EA:
KCAL / DAY: GER + GEF + EA - This option would be possible if the person carries during the 24h of the day any of the devices mentioned above, and the software itself calculates the Kcal spent a day.
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How much energy is needed up to date?
The necessary energy for every day DIt will epend on the objective pursued. Quantitatively, the relationship between caloric intake and energy expenditure, that is the energy balance.
In this way there may be a positive energy balance or with caloric surplus, a balanced energy balance or a negative energy balance or caloric deficit.
Caloric surplus
Normally It is pursued when the objective is the increase in body mass, normally sought an increase in muscle component. On certain occasions an increase in the fatty component is sought, when it is too low.
To achieve this, you can follow the following strategies:
Increased caloric intake. Fundamental aspect
- A caloric intake superior to energy expenditure is calculated
- The new diet must increase protein consumption, up to 2.5-3 gr per kg weight /day
- Carbohydrates are prioritized when training is moderate or high intensity
- Healthy fat intake is prioritized when training is low intensity
How to calculate maintenance calories
When a person wishes to maintain their body mass, he must design an enutritional strategy that covers the energy consumed every day, that is, ingesting the same calories as you spend daily, which is colloquially known as maintenance calories.
Caloric deficit How much?
Finally, If what is sought is a caloric deficit or negative energy balance, with the aim of reducing fat mass, strategies would be the following:
a) Increase the metabolic rhythm at rest:
- Avoid large caloric restrictions so that RMR does not decrease
- Increase muscle mass. The muscle is the one who consumes energy
b) Increase daily energy expenditure (training):
- Increase the quality or amount of training. This plot is responsible for trainers / physical trainers
c) Take an active lifestyle: climb stairs instead of using elevators, move without using motor vehicles (whenever possible), etc.
But be careful, because a program whose objective is weight loss and is based on an excessive caloric deficit, either by a lot of training or by caloric restriction, it can cause certain problems in both men and women:
- Oligospermia / amenorrhea
- Osteoporosis
- Physiological and metabolic alterations: fatigue, immunodefression, anemia, loss of tissue regeneration capacity, etc.
This set of alterations is known as "relative energy deficiency in sport" syndrome. To prevent it, it is key to avoid excessive caloric deficit.
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But How much is excessive?
This syndrome occurs when the Energy availability is below minimums: <30 kcal / kg Free mass fat / day
The Energy availability It is calculated:
(Caloric intake- energy expenditure) / fat-free mass
Therefore, when establishing and guaranteeing the minimum of calories to be ingested by an athlete, it can be calculated after a study of the body composition indicated by the fat free mass in kilos and multiplying is 30.
- For example, in an athlete with 75 kg with 19.2 % fatty, 14.4 kg are fat. Fat free mass would be 75-14.4 = 60.6 kg
- Therefore the energy availability to guarantee would be:
60.6 x 30 = 1818 kcal / day
Not everything is so mathematical
Finally indicate that not everything is so mathematical, because The metabolism of each person is very different and is influenced by many factorsHowever, these types of calculations can guide to have more precise initial references, than with a good monitoring and evaluation program, they can be adjusted.
