Everyone knows that in order to get in shape, you need to eat less and exercise. And it’s quite easy to understand what “exercise” means but the part about “eating less” can cause some trouble. How much should you eat? What can you eat? How many calories a day can you eat? While the first 2 questions should be answered by doctors and professionals, the last one can be answered with this simple formula that we’re going to tell you about in this article.
We at Bright Side want to share a formula that can help you calculate the number of calories you can eat without gaining extra weight.
In 1919, American scientist Francis Benedict and his co-author, James Harris, published a paper on the basal metabolic rate — the amount of energy needed for a body at rest to function properly. In this paper, there was a formula that can help calculate the number of calories taking the weight, the height, the age, and the gender of a person into account.
Because life conditions have changed a lot since the paper of Benedict and Harris was published, in 1990, their formula was updated by a group of scientists including Mark Mifflin and St. Jeor. The basic principle is the same but the numbers have changed. At the moment, the Academy of Nutrition and Dietetics claims 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
So, for a 30-year-old woman with a height of 170 cm and weight of 65 kg, the calculations of calories for the body to function normally at rest is the following:
(10 × 65) + (6.25 × 170) — (5 × 30) — 161 = 1,401.5
The formula also takes your physical activity into account, so you need to multiply your result by a certain number:
- If you don’t have any physical activity and you have to spend a lot of time sitting, then multiply the result by 1.2.
- If you have run a little or do some exercises 1-3 times a week, multiply the result by 1.375.
- If you do a medium amount of sports 3-5 times a week, multiply the number of calories by 1.55.
- If you have 6-7 full workouts a week, then you need to multiply the number by 1.725.
- Finally, if your work is connected with physical activity and you exercise at least twice a week, you need to multiply the result by 1.9.
So, for a girl with the parameters mentioned above who runs a few 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 the research, this formula doesn’t work for everyone because every person’s body has its own metabolism speed and a different amount of muscles. Besides, there are other factors too. For example, this formula doesn’t work for people who are obese and can only be used for people whose weight is normal.
- Those who are planning to lose weight slowly without any risk to their health should decrease the result they get by 250 calories. If you are planning to lose weight more quickly, decrease the result by 500 calories. But remember that the daily norm should not be lower 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 from the example. Let’s imagine that she exercises 3-5 times a week and wants to lose weight safely. This means that she needs to multiply the result by 1.55:
1,401.5 × 1.55 — 250 = 1,922.325
Her diet needs to be planned so that the daily norm is no higher than 1,920 calories. If she eats this number of calories, she will lose about 250 g a week.
If she needs to lose weight more quickly, then the number of the calories she consumes should be about 1,420. This way, she will lose about 500 g a week even without any additional exercises.
Were you surprised by your calculations? Should you be eating less or more according to this formula? Share your thoughts with us in the comments!