Calculate the necessary calories

Learn how to calculate the calories needed for your diet

To be able to have good results, it is not enough to go to train, you also need a good diet.

But before you build your own diet, you need two things.

First you need to define what your goal is.

Do you want to gain muscle mass or lose weight?

Then, with the goal set, you need to know how many calories you must ingest to achieve your goal.

Only after knowing how many calories you need can you create an effective diet to get the results you want.

Let's start.

Mifflin-St Jeor equation

The Mifflin-St Jeor equation is a simple formula for calculating your basal metabolism.

Basal metabolism corresponds to the calories that your body needs to keep functioning in a healthy way.

However, it does not take into account your daily activity, so it is only part of the story.

How to calculate basal metabolism?

The formula for calculating your basal metabolism differs slightly between men and women.

Below is the formula used for each one.


(10 x Body weight) + (6.25 x Height) - (5 x Age) + 5 = Basal Metabolism


(10 x Body weight) + (6.25 x Height) - (5 x Age) - 161 = Basal Metabolism


Manuel measures 1.80m, weighs 60kg and is 23 years old.

He realizes the importance of food to achieve good results, so he decides to calculate how many calories he needs each day.

The account for Manuel is as follows.

(10 x 60) + (6.25 x 180) - (5 x 23) + 5

600 + 1125 - 115 + 5 = 1615

Therefore, Manuel's basal metabolism is 1615 Kcal.

However, this is just the value for Manuel to keep his body functioning, in the minimum conditions.

These are the calories your body uses without Manuel getting out of bed.

In other words, we need to do some more calculations.

Learn how to calculate the calories needed for your diet

Activity level

After calculating your basal metabolism, you need to take your daily activity level into account.

If you take only the calories from your basal metabolism, the result is simple.

You will lose weight.

Use the table below to calculate the number of calories needed to maintain your current weight.

Activity level


Little or no exercise


Light exercise (1 to 3 times a week)


Moderate exercise (3 to 5 times a week)


Intense Exercise (6 to 7 times a week)


Maximum intensity (twice a day, etc.)



You must use the value of your basal metabolism, and multiply by the number that corresponds to your type of activity.

The table is based on the level of exercise, but it is important to also take into account your daily life.

If you only train twice a week, but your work is extremely physically demanding, you should use a higher multiplier.

If, on the other hand, you train five times a week, but spend the rest of the day sleeping, you can use a lower number.

In the case of Manuel, he trains four times a week and during the day he goes to college.

Looking at the table, the correct calculation would be.

1615 x 1.55 = 2503 Kcal

Manuel, in order to maintain his current weight, should ingest approximately 2503 Kcal per day.

Learn how to calculate the calories needed for your diet

Gain or lose weight

Now that you know how many calories you need to maintain your current weight, the last step is missing.

If you want to gain muscle mass, you need to add calories.

If on the other hand, your goal is to lose fat, you must reduce calories.

Let's call Manuel again to illustrate how you should do this.

If Manuel wanted to gain muscle, he should take his 2503 kcal and add 300 kcal.

That is, your muscle mass diet was going to be composed of approximately 2803 kcal.

If, on the other hand, Manuel's goal was to lose weight, he would remove 300 kcal at the amount necessary to maintain his current weight.

That is, to lose weight, Manuel's diet would have approximately 2203 kcal.

Final notes

These calculations offer approximate values, but not exact values.

You should use these numbers as a basis for building your diet, but it is also important to note the results they give you.

If after three weeks you are not able to gain weight with these values, you should increase the calories.

If, on the other hand, after three weeks you are not able to lose weight, then you should reduce.

Also, don't forget to use adequate amounts of each macronutrient to get these same calories.

Our article how much protein do I need per day it helps you in that matter.

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2 comentários

  1. Good afternoon,

    I have read some of your articles on nutrition and training but I would like to clarify the following doubts.

    It is my intention to increase muscle mass in order to define muscles, especially from the trunk upwards. I already understood the importance of food in the goal, but what I ask is as follows:

    - I train 3 times a week. Monday and Friday I train the chest, back and arms. In the fourth workout the legs and abs. Will I have to pay attention to protein and carbohydrate intake only on training days or training and rest days?

    - At the same time I wanted to lose fat located in the belly, which is not much, enough not to show the abdominals (around 2-3 cm). It is possible to reconcile the two objectives or I have to work in parts.

    I already train at a beginner level around 4 months and at the beginning I was not very careful with food, but some weeks I was more careful with food and what I notice is that I can't lose but abdominal fat, on the contrary sometimes I notice changes for more in the abdominal area.

    Can I have a low calorie diet to lose belly and at the same time have good results in bodybuilding training?


    1. Hi Nelson.
      Yes, you should pay attention to your intake of nutrients every day.

      For the rest, you basically have two hypotheses:

      A) You follow a controlled high calorie diet and increase lean mass, and possibly decrease fat mass a little.

      B) You follow a controlled low calorie diet and decrease fat mass, and possibly slightly increase the % of lean mass.

      In hypothesis A, you are not eliminating fat properly, but by increasing the % of lean mass, you are automatically decreasing the % of fat mass.

      In hypothesis B, you are not exactly gaining kilos of muscle, but by decreasing the % of fat mass without losing muscle, you are automatically increasing the % of lean mass.

      However, it is difficult to gain muscle without increasing fat a little and it is difficult to lose fat without losing a little muscle.

      Basically, if you want to increase muscle mass, you will hardly lose that abdominal fat, but if you focus on losing that fat, you will hardly increase muscle mass.

      The ideal is to decide what is most important to you.

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