Home » Metabolism and fat loss – How you burn calories (for fat loss)

Metabolism and fat loss – How you burn calories (for fat loss)

Our metabolism is super important and it is the thing that allows us to stay alive. Your metabolism does more than just burn calories but it is the thing that we are going to focus on in this post!

Know that your metabolism is way more complex and that this is a simplified explanation to give you a basic understanding of the ways it works!

So you don’t just burn calories by exercising if you’d lay in bed all day doing absolutely nothing you’d still burn calories!

In this post, I am going to cover all the different compounds that influence how many calories you burn.


Let’s first cover the basics of our metabolism. This is the process where your body turns what you eat and drink into energy.

Metabolism is a complex process, the calories are combined with oxygen. This will release the energy we need to perform.

The amount of calories you burn on a daily basis is called total daily energy expenditure, or TDEE. You can break this down into further categories:

  • Basic metabolic rate (BMR)
  • Thermic effect of food (TEF)
  • Non-exercise activity thermogenesis (NEAT)
  • Exercise activity thermogenesis (EAT)


BMR, or basic metabolic rate. This makes up the biggest amount of calories that you burn, and the great thing is you don’t have to do anything for it! No really, these calories are used to keep you alive.

Your BMR makes up for 60-75% of your total daily energy expenditure. This is higher for people who are not physically active and lower for those who are.

So your BMR is the calories that you need to keep your body functioning when fully at rest. Stuff like your blood circulation, breathing, body temperature, growth of your cells and brain function.

How many calories you burn trough BMR depends on a couple of different factors like: age, sex, height, and weight. You can use online calculators to get a rough idea of what your BMR is.

So you tend to burn more calories with BMR if you are young, male, tall, and have a higher weight.

You might notice that some teens in puberty can eat anything they want, this is because the metabolism is highest during periods of fast growth.

After you become 30 years old, your metabolism will slow down with about 2-3% of the previous year.

Generally speaking, athletes have ~5% higher BMRs, this is because of their fat to muscle ratio.

BMR versus RMR

Often you will hear these terms, basic metabolic rate and resting metabolic rate, used interchangeably. Both give an indication of the number of calories burned in total rest.

But there is an important difference.

You talk about BMR when measurements are taken after 12 hours of fasting when the digestive system is inactive, and after 8 hours of sleep. The subjects also need to be in a resting position in a dark room.

These measurements are a lot less strict when it comes to RMR. The subjects don’t have to be fasted or spend the night sleeping before the test.


This stands for thermic effect of food. The number of calories that you burn digesting, absorbing and processing the foods you eat.

This is different for every macronutrient. The highest is for protein 20-35%, for carbs and fats it is 5-15%.

Protein is the hardest to break down, that is also why it is the most satiating macro out there.


Non-exercise activity thermogenesis. This sounds more complicated than it is. Right now we are at the things you can influence when it comes to your metabolism.

NEAT is the energy expended for everything we do that is not sleeping, eating or sports-like exercise (1).

Think of cleaning your house, walking the dog, moving around, fidgeting or typing. How high or low your NEAT is, is different for everyone. And you can totally influence this yourself.

It can burn 100-800 calories a day. As you can see there is a really big difference between the highest and lowest number.

Adjusting small stuff like parking your car further away or standing more when possible. These small adjustments may feel like they are not doing much, but at the end of the day they will really add up!


Lastly, you have EAT, not actually eating, but exercise activity thermogenesis. These are the calories that you burn during exercise.

This can be going to the gym, going for a long walk, playing a football game or whatever sport and exercise you enjoy!

This is by far the most changeable factor of your metabolism. So if you want to change one aspect, focus on this one.

Other factors

Here are some factors that influence your metabolism as well. These won’t have a huge impact or account for everyone like the previous ones I mentioned. But definitely can have a small influence.

Having a fever can increase your metabolic rate with about 7%. This is when you have a fever above 98.6 ° F.

Living in a tropical or warm climate also influences your metabolism. It can increase your BMR from 5-20%.

Why is this important for fat loss?

It is important to have a basic understanding of your metabolism for many reasons. This way you know what you can and can’t influence. And how it can help you with weight loss.

The biggest things you can influence are eat, neat and then tef. By starting to exercise more, parking your car further or consuming a higher protein diet.

You can’t do much about your BMR, and that can suck. Because if you are a small female you are going to have a harder time dieting than a tall guy.

When your goal is weight loss you need to be in a calorie deficit, the higher your metabolism the more you can still eat while losing fat. To get a rough idea of the number of calories you burn you can use an online calculator.

Note that these give you a rough estimate, they won’t be spot on. But take this number as a starting point and adjust according to results.

Metabolism and weight

You might want to blame your metabolism for weight gain. But now that there are few cases where a medical problem actually slows down your metabolism.

I often refer to weight gain as more calories in than out. And that is true but it is a bit more of a complicated process.

It also involves your genetics, hormonal controls, environment, sleep, lifestyle, and stress. But these factors tend to result in a higher calorie intake, so that is when we are back to the calories in vs out.

Metabolism boosters and fat burners

You probably have heard of some metabolism boosters or fat burning pills that will magically increase your total energy expenditure. These are often more hype than help.

They will not give you the desired effect and might even do the opposite of what you want.

These supplements are made by companies that are trying to make an extra buck. Their goal is not helping you lose weight, it is making more and more money.

So don’t try and cheat your way to fat loss. There is no easy way to do this, you have to work for it.

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