Every dieting plan is revolved around calorie intake and macronutrients. We adjust calorie intake based on out weight goal.
What are calories anyway and what do they represents?
One calorie is energy required for heating up 1 gram of water for 1°C. In everyday conversation calorie became synonym for kilocalorie kcal. You will often see nutritional value on the back of food packaging that is written in both kcal and kJ-kilojoule. 1 kcal = 4,2kJ
Calorie intake is individual and unique for every person. There are many ways of determining required calorie intake and they are based on calculations of basal metabolic rate (BMR) and physical activities during the day. One of the most precise methods is the Harris–Benedict equation (or the Harris-Benedict principle)
What is basal metabolic rate?
Basal metabolic rate or BMR is energy we spend resting (breathing, sleeping, digesting, brain and heart function…). Men have around 7% bigger BMR than women with the same weight.
How to calculate BMR?
For calculating BMR you need: weight, height, age
|MEN (metric)||(10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
|WOMEN (metric)||(10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
|MEN (imperial)||66+(6.2 x weight in pounds) + (12.7 x height in inches) –(6.76 x age in years)|
|WOMEN (imperial)||655.1 + (4.35 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)|
For precise determination of calorie requirement you have to include physical activities into calculation. So, you multiple BMR with one of those numbers in the list below.
|AMOUNT OF PHYSICAL ACTIVITIES||DAILY KILOCALORIES NEEDED|
|Little to no exercise||1.2|
|Light exercise (1-3 per week)||1.375|
|Moderate exercise (3-5 days per week)||1.55|
|Heavy exercise (6-7 days per week)||1.725|
|Very heavy exercise (twice daily, extra heavy workouts)||1.9|
For example, 21 years old woman, 175cm 70 kg, who works out 3 times per week.
BMR= (10 x 70) + (6.25 x175) – (5 x 21) -161 = 1527,75 ≈ 1528 kcal (BMR=1528 kcal)
1528 x 1.55 =2368.4 ≈ 2369 kcal daily
According to this calculation, she will maintain her bodyweight by consuming 2369 kcal per day. If she wants to lose a few pounds, she should drop down her calorie intake. That means, if she will consume 500 calories less, it would provide her to lose a pound of fat per week. It is a healthy way of losing weight.
Any extremely low-calorie deficit, that is more than 20% less than your basal metabolic rate, is dangerous for your health and it can slow down your metabolism.
Another way to lose 500 calories per day is to eat 250 kcal less and burn another 250 kcal through workout. That doesn’t include moderate activity that you calculate in your daily calorie needs as you can see in the example, so you will have to burn 250 additional kcal through exercise (running, walking, swimming, biking etc.)