Your energy expenditure — How much energy do you need?

What is your energy expenditure? How much energy do you need?

Everyone is different. In addition to our physical attributes, every individual has different energy requirements. In addition, there is some evidence that ability to lose or gain weight is to some extent predetermined by your genetic makeup, and there is not a great deal that you can do about changing that.

On top of your genes, there are many external factors that affect how many calories you need, so any standardized ‘calorie table’ can be nothing other than a very general, broad brush indication of the number of calories that you need. However, the following are generally accepted to be ‘starting point’ guidelines:


In order to get a more accurate picture of exactly how many calories you need, you need to factor in many variables, and after considering what these variables are, you will see how you do this.

Firstly, there are the lifestyle factors to take into account, such as the work that you do, the exercise you take and so on.

These are to a large extent taken into account in the underlying calculation on which the previous chart is based. Someone who is working in a sedentary office based occupation is going to need considerably fewer calories every day than someone who is working on a building site, as an example.

In addition to this, however, your present weight and age will also have an influence on the number of calories you need to maintain your current weight levels.

The more weight you are carrying, the more energy you need to get that bulk moving, while as you get older, your energy requirements gradually decrease as you are likely to engage in less physically activity than you did when you were younger.

Gender is also an influential factor, because women generally need fewer calories than men.

Taking all of these variables into account, what you are looking to do is calculate a ‘Body Mass Ratio’ (BMR) which is not the same as the ‘Body Mass Index’ that we were considering earlier.

What BMR does is provide an alternative method for calculating your daily calorific requirements taking account of variables like age, gender, occupation and present weight.

BMR is calculated as follows:

To calculate your calorie requirements:
The following method uses factors like height, weight, age and sex to determine basal metabolic rate (BMR), using which we can determine yours

Men: BMR = 66 +(13.7 Xwt in Kg) + (5 X ht in cm) – (6.8 X age in years)
Women: BMR = 655 + (9.6 X wt in Kg) + (1.8 X ht in cm) – (4.7 X age in years)

After calulating your BMR, you can estimate your calorie requirements by mulipying your BMR by your activity multiplyier from the chart below:

Activity Multiplier

  • Sedentary = BMR X 1.2
  • Light activity = BMR X 1.375
  • Moderate activity = BMR X 1.55
  • Heavy activity = BMR X 1.725
  • Super active = BMR X 1.9

Yes, the formula is undoubtedly more complex than simply using the previous chart, but if you want a more accurate picture of how many calories you need rather than how many calories some mythical ‘average’ person needs, getting your calculator out and taking a few minutes to do the sums is time and effort very well worth expending.

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