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Calculating your metabolism is the first step, but we also have two calculators that will help you to know your lean body mass index but also what know your muscle-gain potential.
What is basal metabolic rate?
Le basic metabolism represents the minimum energy your body needs to maintain its vital functions at rest. In practical terms, this is the number of calories your body burns every day, even if you were to lie still all day.
The basal metabolic rate is a mechanism that varies considerably from one person to another. To give you a precise idea, let's take the example of two people weighing 80 kg: the first might have a basic metabolism of just 1400 calories, while the second could be as much as 5700 calories! This impressive difference can be explained by a number of factors, which we will explain in detail below.
The body's organs and energy
Each organ in your body consumes a specific amount of energy, and the figures are astonishing (when we talk in kg if below it is not in body weight, but in organ weight):
- Your brain: 240 kcal per kg, (the equivalent of a light meal, just to keep 1 kg of brain tissue working!)
- Your heart: 440 kcal per kg
- Your liver: 440 kcal per Kg
- Your muscles: 13 kcal per kg
- Your adipose tissue: 4.5 kcal per kg
Here is a detailed table of energy expenditure by your organs, based on the latest scientific studies. To illustrate, we have taken as an example a man of 1m80 and 80kg. (considered average) and a woman of 1m65 for 60kg (corresponding to national averages).
| Organs | Kcal/kg/day | % body mass | % of total MB | Example Male 80kg (kcal/day) | Example Woman 60kg (kcal/day) |
|---|---|---|---|---|---|
| Liver | 440 | 2.6 | 19 | 916 | 686 |
| Brain | 240 | 2.0 | 17 | 384 | 288 |
| heart | 440 | 0.5 | 8 | 176 | 132 |
| Kidneys | 440 | 0.4 | 7 | 141 | 106 |
| Muscles | 13 | 40.0 | 20 | 416 | 312 |
| Digestive tract | 200 | 1.7 | 10 | 272 | 204 |
| Adipose tissue | 4.5 | 21.4 | 3 | 77 | 58 |
| Other bodies | 12 | 31.4 | 16 | 301 | 226 |
Factors that influence your metabolism
As explained, we are not all equal when it comes to our basic metabolism.
Body composition plays a major role;
For the same weight, a muscular person will have a higher metabolism than someone with more body fat.
That's why weight training, which builds muscle mass, is an advantage, even during the weight loss phase.
Age also influences your metabolismwith a decrease of 2 to 3% per decade after 20 years. (All the more reason to maintain your muscle mass!)
Genetic factors can vary your metabolism by up to 20% from one family to anotherStudies even show variations of 500 kcal/day between different families.
Environmental factors. Certain lifestyle habits will also affect the basal metabolic rate, such as stress, smoking, coffee consumption or the use of alcohol. fat-burning foods. hyperactivity and even the outside temperature, the cold having the effect of activating your body's heat production and therefore increasing your metabolism.
Gender is also a determining factor Metabolism: given the same characteristics, men generally have a higher metabolism than women, mainly due to their naturally greater muscle mass.
And finally.., certain physiological conditions such as thyroid activity can have a significant impact on your metabolism.
How do you calculate your basal metabolic rate?
To calculate your basic metabolismThere are several scientifically validated methods available, from the most precise to the most accessible. Black's method is one of the most recent and seems particularly reliable for overweight people and senior citizens.
Calorimetry: the most accurate method
If you want to find out your basal metabolic rate with the utmost precision, you'll need to go to a laboratory for a test. calorimetry. This technique measures the heat produced by your body and your oxygen consumption under very specific conditions: fasting for 12 hours, at complete rest, in a room at 22°C.
As you can see, it's not a free technique, and if you follow it up, it can start to become a budget.
Predictive equations: the best compromise
Faced with this complexity, scientists with a passion for bodybuilding have developed several mathematical formulas. Each has its own particularities:
- The equation of Harris-Benedict (1919): a pioneer in this field, but one which has since been overtaken by new methods.
- The Mifflin-St Jeor (1990): slightly more precise, it has become the reference formula of the American Academy of Nutrition.
- The equation of Black (1996): the most recent, which has the advantage of taking into account a wider and more diversified sample of possibilities.
Why so many different formulas? Quite simply because the populations studied, the periods and the research methods have evolved.
For example, Black's formula was developed by studying 574 people aged 2 to 95, deliberately excluding athletes in order to better represent the general population, and not just fans of cast iron!
- Increased metabolism
- Based on 43 scientific studies
- Fat Removal
- Appetite suppressant
How can the results of the calculator be interpreted?
Our calculator provides you with two essential pieces of information: your basal metabolic rate (BMR) and your Total daily energy expenditure (TDEE). These results are calculated on the basis of your personal data and your level of physical activity. (none of this data is stored on our servers)
How can I understand my results?
The calculator displays two main results:
- Your basic metabolism which correspond to the calories your body needs at rest, without any activity.
- Your daily energy expenditure your total calorie requirements, which this time include your physical activity
Level of physical activity
Our calculator takes into account different levels of activity that influence your TDEE :
- Sedentary: little or no exercise (office work, no sport)
- Slightly active: 1-3 sessions/week (daily walk + a few sessions of sport)
- Moderately active: 3-5 sessions/week (regular practice of a sporting activity)
- Very active: 6-7 sessions/week (intense daily training)
- Extremely active: athlete or intense physical work (several sessions a day)
Recommendations according to your objective
Depending on your selected objective, the calculator automatically adjusts your requirements:
Weight maintenance The calculator displays your exact TDEE, which corresponds to your needs to maintain your current weight.
weight loss You'll get a reduced OED of 500 kcal, which scientifically means you can lose around 0.5 kg a week, which corresponds to a healthy weight loss. (A greater deficit could slow down your metabolism)
Weight gain The calculator increases your daily energy intake by 500 kcal, the ideal amount to promote muscle mass gain while limiting fat gain, in other words, dry mass gain.
Monitor your progress and adjust your diet
Research shows that the body continually adapts. To optimise your results:
- Weigh yourself under the same conditions (in the morning on an empty stomach)
- Use a nutritional tracking application to track your calories
- Re-evaluate your needs if your weight stagnates for more than two weeks
These calculations are your starting point, so it's up to you...
Scientific publications on basic metabolism
- "Climate influences on basal metabolic rates in circumpolar populations". (Study showing the impact of climate on metabolism) 10.1002/ajhb.10072
- "Predicting resting energy expenditure from lean body mass and fat mass". (Fundamental research into factors influencing metabolism) 10.1093/ajcn/56.5.848
- "The relationship between basal metabolic rate and body composition in young adults". (In-depth study on the impact of body composition) 10.23751/pn.v22i1-S.9761
- "Effects of body fat mass and body fat distribution on resting metabolic rate in the elderly". (Research into how metabolism changes with age) 10.1053/meta.2001.24871
- "Long-term persistence of adaptive thermogenesis in subjects who have maintained weight loss". (Study on metabolic adaptation during dieting) 10.1093/ajcn/88.4.906
- "Do we need breed-specific predictive equations for resting metabolic rate?" (Research into the ethnic influence on metabolism) 10.1038/s41387-019-0087-8
- "Adaptive thermogenesis in the regulation of human body weight: more a concept than a measurable entity?" (Study on metabolic adaptation) 10.1111/j.1467-789X.2012.01041.x
