Skip to main content

We talk about calories every single day to our clients and we have probably chatted to you reading this email about them after your metabolic or Vo2 test, two of the main services we offer. Just last Tuesday, Health Matters had our busiest day of testing EVER with 40 metabolic tests carried out in one day! We spoke to every single person about calories in versus calories out to help them achieve their goals.

We are all familiar with calories; we have read about them, we have thought about them, we count them, we eat them, we expel them…. But why are they so important to consider when working towards our goal?

First of all, let’s strip it back. What are they?

Calories are the energy we obtain from food. That energy from food contains carbohydrates, fats and protein that is used to fuel and support our body during basic bodily functions, during daily activities and during exercise.

  • Carbohydrate – 4kcal
  • Fat – 9 kcal
  • Protein – 4 kcal
  • Alcohol – 7kcal

When you eat or drink, these four components are broken down in the body to release energy that our body can go on to use.

Why are they important?

Everyone’s individual make up is different, yet we all need energy to fuel crucial functions such as pumping blood, brain function and breathing, to other activities such as walking to work, playing with the kids, and training. We all require calories and energy to function optimally and perform at our best.

However… we are all different and our calorie requirements are individual.

  • If you eat more calories than you expel, you will gain weight.
  • If you eat fewer calories than you expel, you will lose weight.
  • If calorie input equals calorie output, you will maintain weight.

Consumption Vs Expenditure

We consume energy through food.

We expel energy in 4 ways:

  1. Through our Resting Metabolic Rate (RMR) (70%)
  2. Through Non-Exercise Activity Thermogenesis (NEAT) (15%)
  3. Through the Thermic Effect of Feeding (TEF) (10%)
  4. Through Exercise Activity Thermogenesis (EAT) (5%)

Your resting metabolic rate is one of the most crucial factors affecting how your body maintains its weight, this is the energy you burn at complete rest for crucial bodily functions. This accounts for 70% of the energy you expel in a day! When you know this number you know exactly how much food you need to eat to lose, gain, maintain or how much to eat to support performance. For those of you who have tested with us you will have your own unique RMR result, which at the time of testing was 98% accurate.

NEAT, TEF and EAT account for a lot less, which goes to show that understanding your RMR is by far the most important component you need to consider for your overall goal.

Why not use an online calculator?

Well, you can, we are not saying you can’t. But they are wildly inaccurate, it will take a lot longer and involve a lot more guesswork to figure out your RMR. From the 1000’s of clients we have worked with, we can assure you that your metabolism is not broken – your calorie output is simply too high or too low if you are taking an online calculator as gospel.


Calories are energy, they are essential. But they also govern weight loss, gain, maintenance and much more. We are not saying you need to obsess over them, but in our experience we have seen clients try to lose weight for months, years even, with little success for a number of reasons – accountability, adherence, uncertainty, incorrect numbers… to name a few. Remove the guesswork and get tested!

Yours in Health and Fitness,
The Health Matters Team

If you don’t already please follow us on Instagram @healthmattersire and feel free to engage, like, share and comment.

Our articles are published early through our newsletter.

Subscribe for early access