Everyone knows that getting fit requires eating less and exercising. And it’s pretty easy to understand what “exercise” means, but the “eat less” part can cause some problems. How much should you eat? What can you eat? How many calories can you eat a day?

While the first 2 questions must be answered by doctors and professionals, the last can be answered with this simple formula that we are going to talk about in this article.

We want to share a formula that can help you calculate how many calories you can eat without gaining weight.

## Mifflin — St Jeor formula

In 1919, the American scientist Francis Benedict and his co-author, James Harris, published an article on the basal metabolic rate, the amount of energy required for a body at rest to function properly.

In this article, there was a formula that can help calculate the number of calories taking into account a person’s weight, height, age, and gender.

Since living conditions have changed a lot since the Benedict and Harris article was published in 1990, a group of scientists like Mark Mifflin and St. Jeor updated their formula.

The basic principle is the same, but the numbers have changed. At the moment, the Academy of Nutrition and Dietetics states that this formula is the most accurate among others.

**The Mifflin – St Jeor formula looks like this:**

**For women**: (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161**For men**: (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5

Thus, for a 30-year-old woman with a height of 170 cm and a weight of 65 kg, the calorie calculations for the body to function normally at rest are as follows:

(10 × 65) + (6.25 × 170) – (5 × 30) – 161 = 1,401.5

The formula also takes into account your physical activity, so you must multiply your result by a certain number:

- If you do not do any physical activity and spend a lot of time sitting, multiply the result by 1.2.
- If you run a little or did some exercise 1-3 times a week, multiply the result by 1,375.
- If you play sports on average 3-5 times a week, multiply the number of calories by 1.55.
- If you have 6-7 full workouts per week, you need to multiply the number by 1,725.
- Finally, if your work is related to physical activity and you exercise at least twice a week, you must multiply the result by 1.9.

So for a girl with the parameters mentioned above who runs several times a week, the number of calories will be 1,401.5 × 1,375 = 1,927.06. However, if the girl exercises 6-7 times a week, her daily norm would be 1,401.5 × 1,725 = 2,417.6.

## How to use the Mifflin — St Jeor formula

According to research, this formula does not work for everyone because each person’s body has its own metabolism rate and a different amount of muscle. In addition, there are other factors as well. For example, this formula does not work for obese people and can only be used for people of normal weight.

Those who plan to lose weight gradually, without any risk to health, should reduce the result obtained by 250 calories. If you plan to lose weight faster, reduce the result by 500 calories.

But remember that the daily norm should not be less than 1,200 calories for women and 1,400 for men.

Let’s take a look at the Mifflin – St Jeor formula using the same woman as an example. Let’s say you exercise 3-5 times a week and want to lose weight safely. That means you need to multiply the result by 1.55:

**1,401.5 × 1.55 – 250 = 1,922.325**

Your diet should be planned so that the daily norm does not exceed 1,920 calories. If you eat that many calories, you will lose about 250g per week.

If you need to lose weight faster, the number of calories you eat should be around 1420. In this way, you will lose about 500g per week, even without any additional exercise.

Were you surprised by your calculations? Should I eat less or more according to this formula? Share your opinion with us in the comments!

Preview photo credit shutterstock, shutterstock