What Do We Factor in When We Calculate Calories

What factors do we consider when calculating your calories?

Whilst many of us find it foreign, most people now are at least familiar with the concept of calorie counting

Having apps like MyFitnessPal and Cronometer have made the practice much more accessible to the general population. 

The number one question we get is “WHY do I need to count calories in the first place? And the answer is simple. 

‘The secret to success (both performance and body composition) is eating high-quality foods in the right quantities for your goals. 

Counting calories provides you with objective data that enables you to make better judgement calls. “What you track is what you can change” 

We often get asked which factors we take into consideration when we work out an individual’s calorie target and macronutrient breakdown. 

There are a couple of different formulas that can be used (with some taking gender and age into the equation while others don’t). 

Calculating Resting Metabolic Rate (RMR)

Firstly, resting metabolic rate (or RMR) is the amount of calories used per day when at complete rest. It’s basically the “cost” of keeping your internal systems running.

As I said before, there are a number of equations out there to calculate RMR. The reality is that once you input your data, there is only a small difference between any of them. 

We use body fat percentage (from the skinfold testing) and total body weight (scales) to calculate RMR, mainly because it’s simple and effective. As a general rule, the bigger and/or leaner you are, the higher your RMR. It takes more energy to maintain a large male’s frame than it does to maintain a small female’s frame. (even intra-gender) 

Once we have this number, we can get creative with what we do with it. 

“Maintenance” Calories

We also estimate how active you are both inside and outside of the gym, and then apply an “activity multiplier” to your RMR. Sedentary jobs with little gym-based exercise will get a multiplier of 1.2, while hard training and a physically intense job may get a multiplier of up to 1.8. 

Putting this together gives us your “maintenance” calories – the calories you need to maintain body weight each day (given your lifestyle, work and training). 

[There is an art to accurately estimating activity multipliers. It’s incredibly hard to measure scientifically in a lab, let alone in the real world!]

Factoring in Goals

Once we know your maintenance calories we can work out what to do with them. As a rule of thumb, a daily deficit of 500 kcal below your maintenance calories will result in 0.5kg of weight loss each week, and a daily surplus of 5-10% is enough for muscle gain. 

Of course, with time your body will adapt to these new calories and start to plateau. It’s at this point that it’s worth remeasuring and recalibrating your calories to make continued gains. 

[There is a little bit of art that goes on here too. Bigger people can generally be more aggressive with their calories because they have more of them to play with when it comes to fat loss, and certain personality types respond better to the “go hard or go home” mentality. We have to use our judgement as coaches to get that right.]

And that’s the process. It seems simple, and it is once you’ve had lots of practice at it! Knowing how to take accurate measurements and learning to factor in people’s individual differences does make the process more complex, and it does take a significant amount of practice to get that right (it’s why we do it for you!). 


1. Find your RMR (weight, body fat %): This is how much energy you’ll need to keep your body alive if you stayed in bed all day).

2. Calculate your activity levels to find a baseline: This factors in your general day to day life, including work, steps, training etc. 

3. Factor in your goals: Want to lose fat? (deficit). Want to gain muscle (surplus). Want to maintain (maintenance). 

4. Track with a tracking app until you’ve got a deep understanding of which foods a composed of which macro nutrients and the calorie number associated with them. 


Daniel Shute 

Exercise Physiologist 

Manager and Head Coach

BodyByBrando, Waterloo



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