How Many Calories Should You Eat per Day?

Know your numbers



What is BMR?– BMR is the abbreviation of Basal Metabolic Rate. Simply this is the amount of energy you expend each day when at rest. So if you were to sit around all day and do no exercise of any kind this is the amount of calories you would need to consume to maintain your current size and weight.

What is TDEE? – TDEE is the abbreviation of Total Daily Energy Expenditure. This is the amount of calories you burn each day, factoring in your BMR and your activity levels.

What are Macronutrients? – Macronutrients are substances that make up calories and are required in large amounts in your diet. There are three main macronutrients Protein, Fats and carbohydrates.

More about macronutrients here

How to work out your BMR

Mifflin St. Jeor Equation

Female Equation:

BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

Example: Woman weighing 62kg with a height of 155cm and age of 30

10 x 62 = 620
6.25 x 155 = 968.75
5 x 30 = 150
So BMR = …. 620 + 968.75 – 150 – 161 = 1277.75 calories

Male Equation:

BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5

Example: Man weighing 74kg with a height of 177cm and age of 37

10 x 74 = 740
6.25 x 177 = 1106.25
5 x 37 = 185
So BMR =…. 740 + 1106.25 – 185 + 5 = 1666.25 calories

Now that we know our BMR we need to workout our TDEE.

Your TDEE is worked out by taking your BMR and multiplying it by your activity factor.

Little or no Exercise/ desk job
TDEE = 1.2 x BMR

Lightly active
Light exercise/ sports 1 – 3 days/ week
TDEE = 1.375 x BMR

Moderately active
Moderate Exercise, sports 3 – 5 days/ week
TDEE = 1.45 x BMR

Very active
Heavy Exercise/ sports 6 – 7 days/ week
TDEE = 1.725 x BMR

Extremely active
Very heavy exercise/ physical job/ training 2 x/ day
TDEE = 1.9 x BMR

TDEE for our example man and women.

Man: 1666.25 x 1.45 = 2416 (rounded off)
Woman: 1277.75 x 1.45 =1853 (rounded off)

So by eating their TDEE calories, our example man and woman would maintain their current size, weight, body fat etc.

In order for them to lose weight, they would need to reduce their calories and eat below their TDEE, in order to gain weight they would need to eat more.


We need to bear in mind that these calories are a starting estimate and only by tracking our progress can we be sure we are on the right track.

So if you want to lose weight/fat I recommend reducing your daily calories by 400 a day

If after 2 weeks there is no change in weight or body fat then you need to reduce your calories by a further 100 and continue to monitor.

Similarly if you want to gain weight you need to increase your daily calories. I would recommend starting by adding 200 a day. 

Note: For women when tracking you need to keep in mind that your menstrual cycle will affect your weight and it can be up to 5lbs. This is one reason why tracking weight only is not the best indicator of progress. Body Fat %, inches and how you look in the mirror is a better measurement of your progress.


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