How many calories should I be eating?

If we want to maintain our current weight we need to have the same amount of calories as we’re burning each day.

If we want to lose weight we need fewer calories each day.

If we want to gain weight we need more calories each day.

So how do we know how many calories we’re burning each day?

Here’s a 20min live video explaining how you can calculate your Basic Metabolic Rate:

Or if you prefer, read on for the main points:

BMR is your Basal Metabolic Rate – This is the number of calories your body requires to sustain basic life functions such as breathing, circulation, and cell production while at rest. It serves as the starting point for determining your daily calorie needs.

RMR is your Resting Metabolic Rate – Often used interchangeably with BMR however also includes light activities like eating, using the bathroom, stretching etc. For the purpose of this blog I’ll use the more common term “BMR”

Before we get into calculations, keep in mind that numerous factors can influence your BMR eg:

  • % Lean muscle mass
  • Genetics
  • Medications
  • Hormones

While useful, BMR calculations are not 100% accurate

One of the widely used methods for calculating BMR is the Mifflin-St Jeor equation and is as follows:

Step 1: Apply the equation

For Women:

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

  • eg. a 40 year old woman weighing 80kg and 170cm in height
  • 800 + 1062.5 – 200 – 161
  • = 1901.5
For Men:

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

  • eg. a 40 year old man weighing 90kg and 175cm in height
  • 900 + 1093.75 – 200 + 5
  • = 1798.75

Step 2. Adjust for activity level

To determine your total daily calorie needs, factor in your activity level by multiplying your BMR by an activity factor. The commonly used scale includes:

  • Sedentary (little or no exercise): BMR × 1.2
  • Lightly active (light exercise/sports 1-3 days per week): BMR × 1.375
  • Moderately active (moderate exercise/sports 3-5 days per week): BMR × 1.55
  • Very active (hard exercise/sports 6-7 days per week): BMR × 1.725
  • Extremely active (very hard exercise/sports & physical job or 2 x training per day): BMR × 1.9

Remember, if you want to lose weight, you’ll need fewer calories than your estimated total daily requirement.

You’ll also require adequate protein to build lean muscle AND sufficient vitamins and minerals to support your overall health and keep your body functioning at its optimum.

Which is where I can help! If you’d like me to help YOU reach your health and fitness goals join me on our next 4 Week Challenge:

Subscribe to my blog

Enter your email address and receive notifications of new posts by email.

Share this post:


Read more from the SBF Blog