When you know how, counting calories is a simple way to stay on track of your weight goals.
But if you’re a beginner, all those calculations and acronyms can seem a tad confusing.
Fear not, we’ve simplified it down into a few easy steps for you. Read on to find out what a calorie is and how to count them properly…
What is a calorie?
A calorie is a unit of heat, equal to 4.1868 joules. That’s the amount of energy it takes to raise the temperature of 1 g of water by 1°C. Applied to the human body, a calorie is the amount of food energy it takes to generate that same amount of heat.
In terms of the calorie values you see printed on food products, these usually refer to kilocalories (Kcal) – 1000 kilocalories is abbreviated to 1 Kcal.
In this guide, when we refer to a calorie, we mean 1 Kcal. One unit of energy that fuels your body.
What is BMR and TDEE?
Basal Metabolic Rate (BMR): Your BMR is how many calories you need to eat at rest. You need to calculate this number first, so you can work out your TDEE.
Total Daily Energy Expenditure (TDEE): Of course nobody remains inactive for 24 hours a day which. TDEE factors in the extra energy required to go about day to day life, plus any extra energy you spend exercising. Your TDEE is how many calories you should aim to eat to maintain your current weight.
How do I calculate BMR and TDEE?
1. BMR calculation
The sum is based on the Harris Benedict Equation:
Men, BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)
Women, BMR = 447.593 + (9.247 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)
Not got a calculator to hand? Find out your BMR by using an online BMR calculator.
Ben is a 30 year old man, 1.8 m tall and weighing in at 90 kg
BMR = 88.362 + (13.397 x 90) + (4.799 x 180) – (5.677 x 30)
BMR = 88.362 + 1205.73 + 863.82 – 170.31
BMR = 1987.6
2. TDEE calculation
To calculate the number of calories you need to maintain your bodyweight, we now need to apply the activity level multiplier to the Harris Benedict Equation:
Amount of exercise, Activity level multiplier
Little to no exercise, Daily kilocalories needed = BMR x 1.2
Light exercise (1-3 days per week), Daily kilocalories needed = BMR x 1.375
Moderate exercise (3-5 days per week), Daily kilocalories needed = BMR x 1.55
Heavy exercise (6-7 days per week), Daily kilocalories needed = BMR x 1.725
Very heavy exercise (twice daily), Daily kilocalories needed = BMR x 1.9
Let’s say Ben is an office worker who does little to no exercise.
TDEE = BMR x Activity level multiplier
TDEE = 1987.6 x 1.2
TDEE = 2385
That means Ben should eat 2385 calories a day to maintain his current weight.
Calories for fat loss
Let’s say Ben’s fat loss target is 10 kg. He wants to get down to 80 kgs without losing any lean muscle mass.
So Ben begins a workout program, taking it easy to start with but quickly building up to moderate exercise. His TDEE would therefore increase, as he is now expending more energy with his workout program:
TDEE = BMR x activity multiplier
TDEE = 1987.602 x 1.55
TDEE = 3081
However, he needs to run a calorie deficit, eating less calories than his active lifestyle demands to maintain his body weight. But how many less?
1 – 2 lbs of fat per week is considered a sustainable level of fat loss, so Ben decides to stick with a 1 lb a week weight loss.
1 lb of fat contains 3500 calories. To lose that amount in a week, you’d need to reduce your food intake below the maintenance level by 500 calories per day:
Ben’s daily fat loss calorie allowance = 3081 – 500
If Ben restricts his daily calorie count to 2581, he should achieve his fat loss goal of 10 kg in a little over 22 weeks.
Sounds manageable doesn’t it? And because the fat loss is spread over a longer time period, he’s more likely to stabilise his body fat ratio at the lower level.