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How to Calculate the Number of Calories You Should Eat in a Day

Whether you want to maintain your weight or lose or gain a certain number of pounds, you first need to determine how many calories your body burns in a day. There is a very easy formula to determine this. You take your basal metabolic rate and you multiply it by a number that states your level of activity. If you’re wondering what a BMR is and how to calculate it, we’ll explain it all.

Bright Side wants to make your life easier by doing the math for you. Below, you can read different amounts of calories that you need in a day, according to your weight and athletic activity.

You can control how many calories you burn.

Your body is extremely intelligent. It takes the necessary energy to function properly from the food you eat. The amount of energy that your body burns is determined by your metabolism. When you eat more than what your metabolism burns, it stores it as fat. You can’t control how much energy is used for all your systems to function properly, but you can control how many calories you burn by exercising more.

These activities burn energy.

Your body’s metabolic rate is the total energy expenditure burned in a cycle of 24 hours. It consists of 3 main components: your basal metabolic rate, or simply BMR, the thermic effect of food, which means the energy your body uses to digest it, and the energy burned during physical activity. We will concentrate more on the BMR.

Your basal metabolic rate (BMR)

The basal metabolic rate, also referred to as BMR, is the minimum number of calories your body needs when it’s at rest. That means your body needs calories to breathe, to keep the heart beating, to repair cells, to adjust hormones, and more. The BMR takes up most of your body’s metabolic rate — about 2/3, in fact. According to a study, your brain consumes 240 calories to function and your heart, 440.

The Harris-Benedict formula to calculate BMR

The BMR is different for everybody. It depends on a lot of factors, like your body type, the percentage of muscle and fat within your body, age, height, and weight.

There are a lot of equations used to determine the BMR, but the most widely used one is the Harris-Benedict formula. It takes your weight, height, age, and gender into consideration. First, you need to convert your weight and height into kg and cm. And it’s calculated with the equation above.

Let’s say, for example, that your name is Julia. You’re 30 years old, 165 cm (5’4″) and 60 kg (132 lb). We will apply the equation for your measurements:

  • 655 + (9.6×60) + (1.8×165) — (4.7×30) = 655 + 576 + 297 — 141 = 1,387

You can use this calculator for a faster result. Keep in mind that this is an approximate calculation.

Multiply your BMR by these numbers.

1,387 would be the resting number of calories to provide the energy that your body needs in a day. Then, to determine the total amount of calories that you should consume in 24 hours, we need to take into consideration the level of activity you experience.

If you’re sedentary, multiply your BMR by 1.2. If you’re quite active, multiply it by 1.55. And if you’re very active, then you would need to multiply it by 1.7.

To get a better idea, the complete table would look like this one:

  • Little to no exercise: BMR × 1.2
  • Light exercise (1 to 3 days per week): BMR × 1.375
  • Moderate exercise (3 to 5 days per week): BMR × 1.55
  • Heavy exercise (6 to 7 days per week): BMR × 1.725
  • Very heavy exercise (twice a day, very intense workouts): BMR × 2

Now let’s visit our example again. Let’s say you have moderate activity throughout the week. Then we just need to multiply 1,387 with 1.55. The total amount of calories that you would need to consume to maintain your weight would be approximately 2,150 per day.

The total number differs according to your goal.

Anything less than 2,150 kcal per day would result in you losing weight. Anything above that number would make you gain weight. Now, if the goal is to lose some pounds, experts recommend decreasing this number by 500 calories per day, but not more than this. If you want to put on weight and build muscle, you definitely need to eat more.

Have you made your own calculations? What is your BMR and how many calories should you eat in a day? Tell us in the comment section.

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