Whether you want to maintain your weight or lose weight, this depends on a number of factors affecting the delicate balance between calories taken through food and those that are burnt through exercise and activity. Among them, a very important factor is metabolism, i.e. all the biochemical processes of the body.
The knowledge of metabolism’s rate, which changes from person to person, is very important in order to personalize a diet and improve the results of a weight loss program.
You can calculate your basal metabolism rate (BMR) easily, with quick and reliable calculations.
It is important to know how many calories you consume each day in order to keep your weight under control and to improve your fitness. See also: What is calorie cycling?
What is the Basal metabolism rate (BMR)?
Metabolism is the set of chemical and physical processes by which food is digested by the body and converted into heat (which serves to maintain the right temperature of the body); a mechanical energy that moves the muscles and energy which is stored in the form of glycogen (a sugar found in muscle and liver) and fat in the adipose tissue.
When we are talking about basal metabolism we mean the set of chemical reactions that occur in the body in conditions of absolute relaxation, awake and without any psychosomatic stress.
The basic metabolism represents the necessary calories for the body to maintain its vital functions and it constitutes for the 67-70% of the daily energy consumption.
What affects metabolism
There are many different factors that affect the basal metabolism of each person.
• Age is certainly the most important factor. Over the years the basal metabolism is reduced: it is at its maximum point at the newborn baby and decreases slowly, stabilizes during adulthood and then fall even more in old age.
• Even thyroid function affects the metabolic processes. The thyroid, indeed, is the regulator of metabolism: if the thyroid produces fewer hormones (hypothyroidism), the metabolism slows down.
• The metabolism changes in relation to the food consumption. Specifically, the digestion of proteins requires bigger amounts of energy than carbohydrates and fats.
• People with a more developed musculature have a more active metabolism. Muscle tissue burns more calories than the fat tissue. Therefore, the greater muscle mass, the best metabolism. This explains the fact that women burn less calories than men.
See also: How to increase your metabolism
Calorie Consumption and metabolism
We consume calories even while eating
Even during eating, we consume energy. After each meal, the body uses energy to digest all nutrients: the thermogenesis of the food is activated, i.e. both heat production and the body get active for the disintegration and utilization of food.
This process constitutes 5-10% of the total daily energy consumption.
The importance of exercise and activity
The amount of calories that we spend due to various daily activities, from the simplest to the most strenuous, is another important factor.
This factor varies depending on the activities carried out on a daily basis by a person.
Everyone who does intense physical activities or exercise too much spend more calories than people who aren’t very active.
The total energy consumption
The total of the above 2 factors shows the daily energy consumption. This is the total number of calories that should be consumed every day if we want to keep our weight stable.
The factor that can be changed is the one concerning the activities. In all diet programs regular physical activity and a healthy nutrition are combined, in order to reduce the total amount of calories consumed.
How to calculate your BMR?
The calculation of the calories the body spends while performing vital functions is very useful because in this way a weight loss diet becomes more precise and individualized.
In particular, it has been observed that in most cases weight loss can be achieved as long as you follow a diet that provides a number of calories identical to those of the basal metabolism. If for example a person has a basal metabolism of 1,400 calories, it is sufficient to follow a daily program of 1,400 calories.
A simple calculation
Various mathematical formulas have been created in order to calculate the basal metabolic rate, which takes into account some specific parameters, such as weight and height.
These formulas can provide a useful first indication of basal metabolism but they have the disadvantage of being very general and therefore they don’t take into account the facts of each individual i.e. body structure etc. so they are useful for healthy people with normal weight or a few extra pounds.
One of the most commonly used formulas, it’s called Harris-Benedict:
For Women: 655 + (9.7 x weight in kg) + (1.8 x height in cm) – (4.7 x age in years)
For men: 66 + (13 x weight in kg) + (5 x height in cm) – (6. x age in years)
Other more scientific ways to calculate your metabolism
Indirect calorimetric is an effective test, reliable and painless to calculate your basal metabolic rate.
This test can be performed with the colorimetric room or with the calorimeter. By calorimetric the heat that comes out as a result of various biochemical reactions of the body is calculated.
The calorimeter
The most common and reliable test is currently an exam, which uses a small handheld device, the calorimeter.
The device resembles a helmet with two Plexiglas tubes. One brings air from outside and the other sucks the air that the examinee has exhaled. The device operates as a measuring room and is connected to a software that processes the data.
Through the analysis of the substances generated and consumed through respiration, the test verifies how the body uses energy sources.
In essence, it calculates how much oxygen the body consumes and how much carbon dioxide it produces. The calorimeter can measure the amount of oxygen inhaled and thus it calculates how many calories can be consumed.
Moreover, considering the composition of the carbon dioxide out of the body, the calorimeter can clarify in what percentage the different types of foods are consumed: carbohydrates, proteins and fats, managing even to determine which foods are consumed faster and which are slowly digested.
The test takes 45 minutes. It is conducted under the conditions of absolute relaxation; the person is lying on a bed in an environment neither too hot nor too cold. The first signs appear after 15 minutes.
To avoid variations in the results, the person should not exercise, eat, smoke or drink coffee after midnight before the test.
The calorimeter can measure how many calories a person uses a minute: multiply this value for 24 hours, and you have the basal metabolism.
