A unique and immutable rule: the calorie deficit
All “diets” have one thing in common, they are based on this rule: to lose weight you have to create a calorie deficit between what our body needs to function (even while lying down doing nothing) this is called metabolism. base and the energy inputs that we will provide to get there (roughly what we put on our plate). We thus act on the energy balance

This rule is that simple. If mathematically we manage to create a small deficit, gap (this is the real difficulty) and this every day, then the body will draw on its fat reserves to provide the necessary energy it needs. This is one of the fundamental elements on which I will rely.

Conversely, if we consume an energy surplus compared to our needs and our body will store it in the form of fat. The mechanism is quite simple to understand.

Basal metabolism
As seen previously: it represents the energy expenditure (often expressed in calories or in Kcal) per day that our body needs to function in a basic way (breathing, beating of the heart, functioning of the organs, etc …)

You can have fun calculating it and to give you an idea (for information only) the simplest formula is as follows:

Harris and Benedict formula, recalculated by Roza and Shizgal (1984)
The main criteria to be taken into account to calculate the basal metabolism (MB) are: Age (A) in years, height (T) in meters, weight (P) in kilograms and sex.

2 formulas are available: one for women, one for men

Gender Calculation formula MB
Female 9.740 x P + 172.9 x T – 4.737 x A + 667.051
Male 13,707 x P + 492.3 x T – 6,673 x A + 77,607

We note that with an identical profile, the MB is higher in men than in women ….

This is an example of a formula; we will also find the formula of Black et al. (1996) but more complicated … if you search the net you will easily find online calculators

We can also see another thing with the formula: we could say that an obese person with the same weight the same height the same age as a bodybuilder has exactly the same basal metabolism but this is not true at all because muscle mass has an impact on caloric expenditure … the factor of hormones is also to be taken into account in short … each one is unique and the formula should be considered as a good indicator but not a truth specific to you.

Active or not active?
We can also apply an activity coefficient to this basic metabolism (climbing stairs, cycling to work, or sitting on a chair) … it all depends on your daily activity level.

Activity level Physical exercise level Calculation
Sedentary 0 exercise / week MB * 1.2
Slightly active 1 to 3 times / week MB * 1.375
Active 3 to 5 times / week MB * 1.55
Very Active Every day MB * 1,725
Extremely active Physical work or strong athlete MB * 1.9

And how does it work in practice?
Let’s take an example: for a person whose basal metabolism is 2000 Kcal per day. In order to lose weight and burn fat, you have to create a deficit of 200 to 300 Kcal, or try to keep a calorie intake (our meals) of 1700 Kcal / day over a day.

Counting your calories: my opinion

Personally, I don’t really count my calories because I think that if we start to put our noses in it we quickly become a paranoid of measurement, a control professional or a psychopath of the scale and I do not want to this … but I do not throw stones at those who do if it suits them that is the most important.

I think that if there is too much control, there is less pleasure and that is not what I want because I want something simple, without fuss and which seems easy to me to hold. And I think that if the mathematical rule of the calorie deficit is essential, it should not be taken in isolation and many external factors (in particular psychological) condition a loss or a gain of weight