What You Need to Know About Your Calorie Needs

Manipulating your calories to lose weight or build muscle sounds easy, right? After all, it’s just maths... isn’t it?

In a way, yes, but there’s also much more to it. Follow me on this little dive into the science, with a touch of fun, to understand the mechanisms behind weight loss, muscle gain, and weight maintenance.

First of all, I’m sure you already know that your body is a complex machine. To determine how many calories your body needs to reach your goals, you first need to understand how it burns (and stores) calories.

But actually, what are calories? We hear calories here, calories there, but what are they really? And why do we use them to track our weight?

The concept of calories didn’t just fall from the sky. Nope, this is solid science! A calorie is a unit of measurement that represents the amount of energy needed to raise the temperature of one gram of water by 1 degree Celsius. By monitoring your calorie intake and comparing it with your energy expenditure, you can estimate whether you’re consuming more or less energy than your body uses to fuel your metabolism. And ultimately, that can influence your weight.

How many calories does the average person need per day?

Calorie needs can vary considerably from one person to another depending on several factors. These include your sex, your age, your height, and your overall lifestyle.

In general, adults need around 1,600 to 3,000 calories per day.

(Yes, that’s a huge range. So obviously, your individual needs can vary.)

Of course.

The foods you eat and the quantities you eat determine how many calories you consume.

Consuming more calories than your body burns leads to weight gain, while consuming fewer calories than your body burns leads to weight loss, which can include both fat and potentially muscle mass.

That’s why making food choices based on the number of calories they provide becomes especially important for people who are trying to lose weight, maintain their weight, or gain weight, particularly muscle.

What factors affect how many calories you need per day?

As mentioned earlier, several factors influence your daily calorie needs. Let’s take a closer look at these factors and how they interact.

Your Age

Eeeeeh yep, my friend. As you get older, your metabolism naturally tends to slow down, which means your body may need fewer calories. You got it: don’t necessarily eat the same way you did at 22 if you’re now 57.

(Unless you’re still managing to burn the same number of calories. In which case, good luck!)

That’s why teenagers, during periods of active growth, generally need more calories than middle-aged adults. Yep, growing takes a lot of energy!

Your Height and Weight

Your physical size (height and weight), as well as your body composition (your muscle-to-fat ratio), play a role in calculating your calorie expenditure. If you’re over 1.90 m tall, for example, your energy needs won’t be the same as someone who is 1.70 m tall.

People who are larger, either in terms of height or percentage of muscle mass, can burn more calories at rest and may therefore need more calories to meet their daily energy requirements.

Sex and Hormones

Sex and hormonal differences can significantly influence your calorie needs.

Men often have more muscle mass and a higher energy expenditure, meaning they generally require more calories.

Women, meanwhile, can experience variations in appetite and energy expenditure throughout their menstrual years due to hormonal fluctuations.

Activity Level

Your lifestyle and activity level have a huge impact on your calorie needs.

People with physically demanding jobs or who regularly practise intense sports will naturally burn more calories and therefore need a higher calorie intake to maintain their energy balance.

Of course, the opposite is true for people with sedentary jobs, such as office work, who don’t exercise very much. They will generally burn fewer calories than someone who trains regularly.

Certain Medical Conditions and Medications

Certain medical conditions, such as thyroid disorders, can affect your metabolism and therefore change your calorie needs. But don’t panic, I can already see you looking at me with huge eyes. Most of the time, this isn’t the reason. There’s a much greater chance that your weight loss isn’t happening because your calorie intake has been miscalculated than because of an underlying medical condition.

It’s also worth knowing that certain medications can influence appetite, energy expenditure, or nutrient absorption, which can further affect your daily calorie requirements. This can include certain steroids, antidepressants, and other medications.

Basal Metabolic Rate (BMR)

Your basal metabolic rate represents the amount of energy your body uses at rest to perform essential functions such as breathing, circulating blood, and regulating your body temperature.

Your BMR is influenced by factors including genetics, muscle mass, and age, all of which contribute to your overall daily calorie needs.

Your Goals

Whether your goal is to lose weight, build muscle, or maintain your current physique, your objective will influence your calorie needs.

Weight loss generally involves a controlled reduction in calorie intake, while building muscle usually requires additional calories to support growth and recovery.

So, what are the processes that actually affect the way you burn calories, you ask?

Here are the different ways your body burns calories.

Exercise Activity Thermogenesis (EAT, not quite as catchy as TAP the airline for anyone who needs a holiday ;))

EAT refers to the energy your body uses during intentional physical activity, such as brisk walking, running, strength training, fitness classes, or any other exercise you consciously include in your routine to work towards a specific goal.

Contrary to what people often think, EAT represents a relatively small portion of your total daily energy expenditure, around five to ten percent on average. (Of course, this percentage can vary.)

For most people, although EAT is undeniably beneficial for overall health, well-being, and weight loss, its direct impact tends to be relatively limited. What matters more is the combination of all the different factors involved in weight loss or muscle gain.

Non-Exercise Activity Thermogenesis (NEAT)

NEAT includes the calories you burn through your daily physical movements outside of structured exercise.

It’s the energy your body uses when you do things like cooking, cleaning, shopping, or even dancing around with a wooden spoon in your hand while singing like Beyoncé. Basically, these are all the movements that don’t count as planned exercise.

Despite being easy to overlook, NEAT has remarkable potential to influence your metabolism and calorie expenditure. It can account for around 15 to 30% of your daily calorie expenditure. While it doesn’t replace intense training, it still represents a significant portion of the calories you burn every day.

Environmental conditions, genetics, the type of job you have, and your lifestyle all contribute to how much NEAT varies from one person to another. A sedentary job and a physically active job can therefore create noticeable differences in the number of calories burned each day. For example, a teacher won’t necessarily burn the same number of calories as a construction worker.

If you want to increase your NEAT, small changes can help. Choosing a standing desk at work instead of sitting all day can be one option, as standing generally burns more calories per hour. (Just don’t forget to take breaks and sit down from time to time.) Walking whenever you can or parking further away from your workplace are also simple ways to increase your NEAT.

I’m sure you’ll agree that its impact goes beyond simply burning calories. It encourages a lifestyle where movement becomes part of your entire day. This has an impact on your overall energy balance, but potentially also on your long-term quality of life. It’s an aspect of fitness and general well-being that shouldn’t be overlooked.

Thermic Effect of Food (TEF)

The Thermic Effect of Food (TEF) is the energy your body uses during the digestion, absorption, and metabolism of the food you eat. In other words, some foods actually require more calories to process than others!

Think of it as an energy cost your body has to pay to process the nutrients from your meals. Or like the government taking a small part of your income to keep everything around you running! And speaking of food, if you’re interested, I wrote an article about The Good Crap: Why We Eat Too Much of It and How to Avoid It.

It’s surprisingly useful if you want to avoid swallowing way more calories than you realise!

TEF represents around 10% of your daily calorie intake. So, if you eat 2,000 calories, roughly 200 calories may be used simply to digest and process that food.

The composition of your plate has a big influence on your TEF. Different macronutrients, carbohydrates, fats, and proteins, require different amounts of energy for digestion and metabolism.

Protein and complex carbohydrates have a higher thermic effect, meaning your body uses more energy to break them down. Fats and simple carbohydrates, on the other hand, generally have a lower thermic effect and therefore require less energy to process.

To go into a little more detail, here’s how each macronutrient influences TEF:

Fat: 9 calories per gram; TEF ranges from 0 to 5 percent = up to around 0.45 calories per gram of fat used during digestion and processing.

Carbohydrates: 4 calories per gram; TEF ranges from 5 to 15 percent = around 0.2 to 0.6 calories per gram of carbohydrate used during digestion and processing.

Protein: 4 calories per gram; TEF ranges from 20 to 30 percent = around 0.8 to 1.2 calories per gram of protein used during digestion and processing.

This is one of the reasons why a high-protein diet can offer a metabolic advantage and also help you stay fuller for longer. The same principle applies when choosing less processed, complex carbohydrates instead of simple carbohydrates.

Fats have the lowest thermic effect, but that doesn’t mean we don’t need them. Healthy fats, such as those found in avocados, salmon, nuts, and seeds, play essential roles in maintaining normal bodily functions, protecting your organs, and providing a source of energy.

And in case you’ve ever wondered, what you eat is definitely more important than when you eat when it comes to calorie expenditure. Although some people believe that eating a large breakfast increases daily calorie expenditure, the impact of meal timing on TEF remains uncertain.

Total Daily Energy Expenditure (TDEE)

TDEE is the total amount of energy your body uses in a day. The components we talked about just above all add together to form your TDEE, keeping in mind that these values can vary depending on the person and their lifestyle:

Component	Percentage of TDEE	Description
Basal Metabolic Rate (BMR)	Around 70%	Calories used for essential functions at rest, such as breathing and blood circulation
Thermic Effect of Food (TEF)	Around 10%	Energy required to digest, absorb, and metabolise the food you eat
Exercise Activity Thermogenesis (EAT)	Around 5%	Calories burned during intentional exercise such as strength training, running, etc.
Non-Exercise Activity Thermogenesis (NEAT)	Around 15%	Energy used during everyday activities that aren’t structured exercise, such as walking, household chores, etc.

As you can see, BMR forms the foundation of your calorie expenditure, while TEF, EAT, and NEAT add on top of it.

Together, these determine your daily calorie needs and, by extension, how many calories you burn.

If you’re working towards a specific fitness goal, such as losing weight or building muscle, your TDEE and calorie needs will change as you progress. Yep, as you lose fat or build muscle, your metabolism adapts to your new body composition, which can influence your calorie needs throughout your fitness journey.

If you turn into the Hulk, you’re going to have to eat, amigo(a). And plenty of protein too!

That’s all from me :), thanks for reading! I hope you enjoyed it, learned something from it, and that it helped you see things a little more clearly.

If you still have questions, don’t hesitate to book a discovery session with me. It can also be done online.

We’ll calculate your calorie needs, discuss your goals in more detail, and work out the best strategy to help you achieve them.

And finally, we’ll finish everything off with a short workout.

And we’ll have some fun doing it!

B, out.