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Energy Requirement Terminology & Calorie Calculations

Before we get stuck in, if this article could be triggering in any way to you, please don’t feel the need to read on.

Repairing your relationship with food first and foremost is of the utmost importance. I am 100% behind this message.

This article is simply to explain energy in a mathematical, logical way, for people who may be interested in learning about the ‘science’ side of energy intake and expenditure in more detail.

If you feel that your relationship with food could do with some work, firstly you are not alone, and secondly, Laura Thomas, PhD wrote a fantastic book all about this, called ‘Just Eat It’, so definitely go and check it out if this resonates with you.

I want to say this as a disclaimer before I start, I am a medical doctor and I’m not a nutritionist or a dietician (yet). However, I do understand how to interpret scientific evidence, I have a basic level of training in nutrition through my medical school degree, I did a university level research project (BMedSci) and I have a particular interest in the specialist area of lifestyle medicine, which includes nutrition.

All of the sources of my information are from credible, trusted and respected professionals in their field. I like to translate the science for the public and my patients to understand, so they feel empowered to take an active role in managing their health. So now that’s done, let’s get started.


- Don’t over think it, this article is just to help give you a starting point. The real accuracy comes from testing it and seeing how your body responds. When you start tracking things, don’t get caught up on precise grams of macros or to the exact calorie. Aim for +/- 10% of these numbers.

- You can still enjoy life. You can still go out to restaurants and have the foods you enjoy. I love the quote, ‘Taking the time to spend time with the people closest to you is more important than keeping ‘on track’ with your diet’. Don’t feel guilt or shame towards food, it is something to enjoy and no food is inherently ‘bad’ or ‘good’, just some are more nutritious than others.

- Make sure your nutrition decisions come from a place of positivity, not fear or restriction. Eat the way you do because you enjoy it and its consequences. If you feel great as you are, don’t feel you NEED to change. In order to be healthy, you need a healthy relationship with what you eat first and foremost.

- Trust your body composition change and performance more than any calculation. These are not exact figures, they are just estimates based on scientific evidence. Just judge it on how things are progressing for you as an individual.

So, let’s dig in….

TDEE, BMR, NEAT, TEF, EAT – know what they all mean? These terms are thrown around all the time in the health and fitness industry, and are actually really useful to understand when it comes to goal setting for health, whether that’s for muscle gain or fat loss. Today I’m going to give YOU the tools to be able to manipulate these metrics yourself.

The Components of Total Daily Energy Expenditure

TDEE – Total Daily Energy Expenditure. This is is the amount of calories you burn each day. TDEE is not just a single measure, but is calculated as a sum of the components of different energy expenditures, during activity and rest. The equivalent phrase to this is your ‘maintenance calories’ required to remain at the same body weight, with your current activity levels.

NREE Non-Resting Energy Expenditure. These are the calories we burn by doing activities such as exercise, eating and walking.

EAT – Exercise Activity Thermogenesis. This is the energy that you burn when you go to the gym. As you can see from the illustration, it actually makes up a very small amount of your TDEE. By not paying attention to the other components of TDEE, you are only manipulating a very small part of the puzzle, when, for example, fat loss is the main goal.

TEF – Thermic Effect of Food. We have to produce heat to digest food, especially protein. So when we have a high protein diet, not only will we fill more satiated (full), it also increases the energy burned through TEF. We will burn approximately one third of the calorie content of protein through TEF. If you look at the illustration, potentially manipulating TEF by having a higher protein diet can have equal, if not more, amounts of benefit for fat loss than your exercise regime - MIND BLOWN. A good place to start for protein intake if you have no idea, is 2g/kg of body weight per day (more on macro splits in a future article).

NEAT – Non-Exercise Activity Thermogenesis. This is the movement we do, other than our scheduled exercise. NEAT is about getting off the bus 1 stop earlier, taking the long route home, walking somewhere instead of driving, going for a walk in our lunch breaks or standing instead of sitting down when the opportunity arises.

REE Resting energy expenditure – You guessed it, this is the energy you burn whilst your body is at rest and it is comprised of your BMR.

BMR – Basal Metabolic Rate. This is the energy burned just lying in bed, carrying out bodily functions. Your BMR is the amount of calories you require on a daily basis, just to keep your systems functioning for survival. A person’s BMR changes with the amount of muscle mass they have, (i.e. BMR increases with more muscle mass). As you can see from the illustration, this is a very large part of the TDEE puzzle, and it’s why resistance training and weightlifting can be favourable when goals are orientated around body composition. You are manipulating a large part of the puzzle by potentially increasing the calories burned from increasing your BMR. There are plenty of other benefits to regarding resistance training too, but I’ll save this for another time!

So, now we’ve been through all the terms, you will be able to understand how to manipulate each of these for your goals, whether that is for fat loss or muscle gain. So let’s go through the steps.


There are many different equations to calculate BMR, all of which differ only slightly in results. Please see below for an example from Sigma Nutrition:

The Joseph Agu estimate is the easiest, most simple way to calculate BMR (the 2 calculations at the bottom of the picture).


In order to calculate an estimate of your TDEE, you need to multiply your BMR calculated above by an activity multiplier (see below):

So using the example above of the 78kg male:

- 78kg x 24.2 (from no.1 equation) = 1887.6 (rounded to 1888kcals) is his BMR, the amount of calories he burns at rest.

- If he was moderately active, we then do 1888 x 1.55 = 2926 kcals, this would be his TDEE, or his ‘maintenance calories’.


The following percentages are what the evidence has shown to be good starting points for either of these goals.

If fat loss is your main goal, calculate 10-20% of your TDEE/Maintenance calories, depending on how aggressive a deficit you want to create, and take this away from TDEE to create your daily calories.

E.g. 78kg man above, 15% of 2926 kcals= 438.9 kcals.

2926 kcals – 438.9 kcals = 2487 kcals per day.

If muscle gain is your main goal, calculate 10% of your TDEE, and add this on to create a small surplus to your maintenance calories.

E.g. 78kg man above, 10% of 2926 kcals = 292.6 kcals.

2926 kcals + 292.6 kcals = 3218 kcals per day.

Use these as guides/estimates for your goal calories, record what you eat over a 7 day period and weigh yourself at the beginning and at the end of the week. If nothing happened and fat loss is the goal for example, start by reducing calories by 10% or 15%. Wait 1-2 weeks whilst adhering to this and if you lose weight, you have found out the amount of calories you require for fat loss FOR YOU. Just remember that a sensible deficit you stick to will always outweigh an extreme one that you don’t.


There are plenty of ways to track progress and what you’re eating during the period of striving for your goal. If something like ‘MyFitnessPal’ could be triggering or feels too ‘extreme’ for you, you absolutely do not have to use it.

Any of the following methods can be used:

1) Detailed macronutrient tracking using MFP if you like or if you have specific body composition goals. Using apps like this can be helpful, as it takes a lot of guesswork out of the equation and is easy to visualise. This detailed approach is definitely not necessary for most people, and can feel quite a daunting task if starting with this.

2) Hit your approximate calories and protein – just logging the approximate foods you’re eating and monitor that you’re averaging out the kcals over the week that you calculated using the equations above (x by 7 to get your weekly intake) and hitting your protein goal.

3) Check your intake intermittently and adjust as needed – this is an option if you’ve tracked before, feel aware of portion sizes and eat similarly each day. Once a week, plug in your intake for that day into an app and adjust accordingly. E.g. If you find you’re not eating enough protein, just add in protein into your afternoon snack moving forward and repeat the process the following week.

4) Track your body weight or metric of choice (e.g. waist circumference, pictures for yourself etc) and increase/decrease food intake based on the rate of change. This is a more relaxed approach and may produce slower results as a lot of guesswork is involved, but avoids the use of trackers if that is not your thing.

I hope you’ve found this article useful, I would be so grateful if you feel like sharing, if you found this interesting or helpful! You can find me on social media on instagram, @drlululittle and let me know if you have any questions. I’d be really interested to hear your responses to this and stay tuned for more to come soon!

- Dr Lulu Little



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