Obesity has become a growing public health concern in recent decades, In Issues relating to Weight Loss: How to Count Your Calories becomes imperative. According to the Centers for Disease Control and Prevention (CDC), the percentage of adults over the age of 20 who were overweight or obese in the US as of 2010 was nearly 70%.
The number of calories you should eat each day depends on several factors, including your age, size, height, sex, lifestyle, and overall general health. A physically active 6ft 2in male, aged 22 years, requires considerably more calories than a 5ft 2ins sedentary woman in her 70s.
It has been discovered that even factors such as how you eat your food can influence how many calories get into your system. The longer you chew your food, the more calories the body retains, a team from Purdue University found
Recommended daily calorie intakes vary across the world.
What is the difference between calories and kilocalories?
Scientifically speaking, one kilocalorie is 1,000 calories. However, the term calorie in lay English has become so loosely used with the same meaning as kilocalorie, that the two terms have virtually merged. In other words, in most cases, a calorie and kilocalorie have the same meaning.
A kilocalorie is the amount of energy required to raise the temperature of 1 kilogram of water from 15° to 16° Celsius (centigrade) at one atmosphere.
A “small calorie” refers to the traditional scientific term of calorie, meaning one-thousandth of a kilocalorie.
Internationally, most nations talk about food energy in kJ (kilojoules). 1 kcal (kilocalorie) = 4.184 kJ.
In this article, the term “calorie” means the same as “kilocalorie” or “kcal”.
How many calories do I need per day?
The Harris-Benedict equation, also known as the Harris-Benedict principle, is used to estimate what a person’s BMR (basal metabolic rate) and daily requirements are. The person’s BMR total is multiplied by another number which represents their level of physical activity. The resulting number is that person’s recommended daily calorie intake in order to keep their body weight where it is.
This equation has limitations. It does not take into account varying levels of muscle mass to fat mass ratios – a very muscular person needs more calories, even when resting.
How to calculate your BMR
- Male adults
66.5 + (13.75 x kg body weight) + (5.003 x height in cm) – (6.755 x age) = BMR
66 + ( 6.23 x pounds body weight) + ( 12.7 x height in inches ) – ( 6.76 x age) = BMR
- Female adults
55.1 + (9.563 x kg body weight) + (1.850 x height in cm) – (4.676 x age) = BMR
655 + (4.35 x kg body weight) + (4.7 x height in inches) – (4.7 x age) = BMR
You can use the BMR calculator by clicking here and work out your BMR.
Applying levels of physical activity to the equation
- Sedentary lifestyle – if you do very little or no exercise at all
Your daily calorie requirements are BMR x 1.2
- Slightly active lifestyle – light exercise between once and three times per week
Your daily calorie requirements are BMR x 1.375
- Moderately active lifestyle – if you do moderate exercise three to five days per week
Your daily calorie requirements are BMR x 1.55
- Active lifestyle – if you do intensive/heavy exercise six to seven times per week
Your daily calorie requirements are BMR x 1.725
- Very active lifestyle – if you do very heavy/intensive exercise twice a day (extra heavy workouts)
Your daily calorie requirements are BMR x 1.9