CALORIES

Talking about healthy eating? Then you'll soon be talking about calories. All the food we know contains calories. But a lot of people don't know exactly what calories are or what they do. You can't live without calories, but too many isn't good either. Do you want to know exactly what calories are and what they do? Keep reading, because on this page we tell you everything about them!

CONTENTS

• What are calories?
• What do calories do?
• How many calories you can have per day
• The effect of a healthy diet
• How calorie burning works

WHAT ARE CALORIES?

Before we dive deeper into the world of calories, it helps to know the basics. What are calories, for example? Where does the name come from? And how did we end up so focused on calories? To answer that last question, we have to go far back in time to the 19th century.

Calories were first introduced in the early 19th century by a French physicist called Nicolas Clément. He defined the calorie as the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. We still use that definition today. At the end of the 19th century, we also began using the term calories for our food. Scientists started measuring the energy content of different foods. They wanted to learn how the human body gets energy from food. This research led to tables with the calorie values of common foods.

In the course of the 20th century, counting calories became a popular method of weight management. It gave people a way to control their energy intake. In recent years, however, we've realised that not all calories have the same effect on our body. The quality of calories is just as important as the amount we take in.

WHAT IS THE DEFINITION OF CALORIES?

As we now know, a calorie is a unit of energy. When we look at food, calories refer to the amount of energy that food and drink contain and can supply to our body. Without these calories, our body can't function. You can compare it to the fuel in a car. Without fuel, your car can't run either.

We use this energy for every activity our body does. Of course, that includes exercising and walking, but breathing and sleeping also cost us energy. Even when your body is completely at rest, you need energy. Your vital functions, such as breathing and blood circulation, have to keep going. For all of this you need energy – and so calories. The amount of energy you need is expressed as basal metabolic rate and resting metabolic rate. But what exactly is the difference?

BASAL METABOLIC RATE AND RESTING METABOLIC RATE

Basal metabolic rate (BMR) is the amount of energy (in calories) your body needs to function at rest. Think of your vital functions, as described above. Your BMR makes up the largest part of your total energy use, around 60 to 75 percent. A person's BMR is influenced by a number of factors: your sex, age, weight, height, body composition, genetics and general health. If you have a lot of muscle, for example, your BMR is automatically higher. That's because muscle uses more energy than fat.

Resting metabolic rate (RMR) is similar to your BMR, but slightly different. Your BMR is measured under strict, specific conditions. Your RMR, on the other hand, can be measured at any time of day. Your RMR is always a little higher than your BMR, because it also includes the energy needed for light activities such as standing and sitting.

WHAT IS THE DIFFERENCE BETWEEN KCAL AND CALORIES?

Chances are that when you look up the number of calories in a certain product, you're looking at the number of kcal . But did you know there's a difference between calories and kcal? In nutrition science, the term 'calorie' is often used to refer to what is actually a kcal. Kcal stands for kilocalorie, and it's the amount of energy needed to raise the temperature of one kilo of water by 1 degree Celsius. So there are 1,000 calories in 1 kcal.

So when we talk about calories in our food, we're actually talking about kilocalories. If a label says a product contains 150 calories, that's actually 150 kilocalories.

HOW ARE CALORIES MEASURED?

We now know the history of calories and what calories are, but how do we measure how many calories something contains? The calories in your food are measured using a device called a 'bomb calorimeter'. Food is placed in this machine and burned. The heat this produces is used to heat a certain amount of water. By looking at how many degrees the water temperature rises, scientists can calculate how much energy the food contains.

Of course, this is all very general, and as you've already read, every body processes calories differently. That's why it's good to know that how your body uses calories depends on a number of factors. Think of the type of food, your metabolism and the way the food was prepared. The number of calories on the label of a piece of meat, for example, is therefore an estimate of the number of calories in the product.

WHAT DO CALORIES DO?

You now know the basics of calories, and you've probably already found out that a calorie is more than it might seem at first glance. But now that you know the basics, it's time for the next step. What exactly do calories do in your body? Why do we need them, and what happens in your body when we take in calories?

USING CALORIES FOR ENERGY

A calorie is a unit of energy, so it makes sense that your body gets energy from calories. When we eat food or drink, we take in calories. Our body breaks down the nutrients in the food we consume. We're talking about protein, carbs and fat. By breaking down these nutrients, your body produces energy, in other words calories. Our body uses this energy to carry out all its functions. From basic activities to intensive ones such as exercise. We call the process of converting food into energy metabolism. During this process, the calories in the food we eat are combined with oxygen to produce the energy our cells need to function.

WHY CALORIES ARE IMPORTANT FOR OUR BODY

That calories are important is clear from the text above. But what makes taking in calories so important for your body?

Calories are vital for our health and wellbeing. Without calories, your body can't carry out any of its functions. You would no longer be able to breathe, and your body couldn't regulate its own temperature. You also couldn't walk, cycle or exercise intensively if you didn't take in any calories.

HOW MANY CALORIES YOU CAN HAVE PER DAY

Now we know what calories are and how important they are, it's time to look at calorie intake. After all, if calories give you energy, why not take in as many as possible? Unfortunately, it doesn't quite work like that. The number of calories you need per day depends heavily on a number of factors. It's good to know how many calories you can have per day, so you can support your health as well as possible.

WHY THERE IS A LIMIT ON THE NUMBER OF CALORIES

Although calories are essential for our body to function, it's important to know that there's a limit to the number of calories you can take in per day. Consuming too many calories can lead to weight gain and health problems. That's because every calorie we consume but don't use for energy is stored by our body as fat. If we consistently consume more calories than we burn, this can lead to weight gain. Consuming too many calories can also lead to nutritional deficiencies and health problems such as heart disease, diabetes and certain types of cancer.

THESE FACTORS DETERMINE YOUR CALORIE INTAKE

Every body is different, every rhythm is different and, really, everyone is different. That's why we can't say exactly how many calories you can have per day. A few factors determine how many calories you can take in per day. We've put these factors in a clear list for you:

• Sex

• Age

• Weight

• Height

• Activity level

• General health

Why are these factors so decisive? Take a young boy, for example. Boys are much more active than, say, an old man. Because they're more active, they have more energy and so need more calories. Men generally need more calories than women. This is partly because men have more muscle than women. This is genetically determined. To supply all this muscle with energy, men need more calories.

If you live a physically active life, you also need more calories than someone who sits all day. If you're overweight and trying to lose weight, you need to take in fewer calories than you can have per day. That way your body starts using its reserves. More on that later on this page.

HOW DO YOU CALCULATE YOUR CALORIE NEEDS?

There are several ways to calculate how many calories you need per day. One of the most widely used methods is the Harris-Benedict formula. This calculates your basal metabolic rate (BMR). The calculation then adjusts this for your activity level. To calculate your BMR, you can use the following formulas:

For men: BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) - (5.677 x age in years)

For women: BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) - (4.330 x age in years)

Once you've done this calculation, you multiply your BMR by a factor that matches your activity level. For the full calculation and the factors you need to combine your BMR with your activity level, we recommend reading our article on calculating your calorie needs. There we go deeper into how to calculate your calorie needs and what this means for your diet.

BURNING EXTRA CALORIES

You can put your body in a calorie deficit by eating healthier and taking in fewer calories. But you can also burn extra calories by moving more. Exercise burns calories because it costs extra energy. How many calories you burn while exercising depends on certain factors. Think of the type of sport, the intensity, the duration, your own body weight and your fitness level. If you go running at high speed, you burn more calories because it takes more effort than walking, for example. If you walk for an hour versus running for a quarter of an hour, you may burn more by walking because it takes longer.

There are several online tools available to measure how many calories you burn while exercising. These can be useful to help you balance your calorie intake and the calories you burn. This is especially handy if you want to lose weight or are working towards a specific goal. It is very important to remember that these are only estimates. No tool can track how many calories you actually burn. That depends on your metabolism and the intensity of your training.

DIFFERENCE IN CALORIE INTAKE BETWEEN MEN AND WOMEN

As we mentioned earlier, the number of calories you can take in depends on your sex. A man can take in more calories than a woman. This has to do with genetics. Women have more fat tissue than men, while men have more muscle tissue than women. These are all factors that determine how many calories you can take in per day.

To go further into these differences, we've written two in-depth blogs on how many calories you can have as a man and how many calories you can have as a woman per day.

THE EFFECT OF A HEALTHY DIET

You now know that you can influence your calorie needs by exercising. But did you also know that your food and a healthy diet matter a great deal when it comes to calories? Managing your calorie intake is important for a healthy diet. Counting calories isn't the only thing that matters. The quality of the calories and the right nutrients matter too.

THE IMPORTANCE OF GOOD FOOD CHOICES

Two products can both contain 200 calories, while their nutritional values and effects are worlds apart. That's because not all calories are equal. They do provide the same amount of energy, namely 200 kcal, but the nutrients in the product can differ. The effects they have on your body are also very different. The calories from a doughnut aren't equal in nutritional value to the calories from an apple. An apple contains much more fibre, vitamins and other nutrients you need.

This is exactly why it's important to make the right food choices. Choosing food or drink with a high nutritional value while limiting 'empty calories' is an effective way to improve or maintain your health.

FEWER CALORIES AND NO HUNGER: HERE'S HOW

We can already hear you thinking: "If I eat fewer calories, won't I get hungry?" It's possible, but it doesn't have to be that way. Certain factors mean you won't walk around hungry all day when you're in a calorie deficit.

Eating foods rich in fibre is a good tip if you don't want to feel hungry. Fibre helps you feel full without eating a lot of calories. Fibre slows down your digestion, so you stay full for longer. Good sources of fibre are fruit, vegetables, wholegrain cereals and pulses.

Protein is also important if you want to avoid feeling hungry. Protein also helps you feel full. This is because protein is fairly filling, so you feel satisfied. You don't have to eat a lot of calories for this, because protein is healthy. On top of that, protein is perfect to use as sports nutrition.

Other handy tips are drinking enough water and eating fewer processed foods. Our body can sometimes mistake thirst for hunger. If you drink enough water during the day, this feeling goes away. Processed foods often contain a lot of calories but few nutrients. An unhelpful and unhealthy choice.

Do you want to know everything about eating fewer calories and what's best to eat? Then read our interesting article on eating fewer calories, where we explain which foods contain the fewest calories and how to follow a reduced-calorie diet.

HOW CALORIE BURNING WORKS

Most people probably know that you can also burn calories. That's how you lose weight or are able to eat more. The number of calories you burn per day is important for losing weight and for your general health. But how you burn calories may not be clear to everyone yet. We'll take you through it and explain how calorie burning works.

THIS IS HOW YOUR BODY BURNS CALORIES

Your body is actually busy burning calories all day long. You need energy for everything you do, and to get that energy your body burns calories. This is called metabolism. We can split your metabolism into three main parts:

• Basal metabolic rate (BMR): we've mentioned this part before. Your BMR is the amount of energy your body uses to carry out its basic functions. Your BMR makes up around 60-75% of your total energy use.

• Thermic effect of food: this is the energy your body uses to digest, absorb and metabolise your food. This part is around 10% of your total energy use.

• Physical activity: physical activity covers a lot. From climbing stairs to exercising. The percentage of your energy use therefore depends on how much physical activity you do and at what intensity.

HOW THE BURNING PROCESS WORKS IN YOUR BODY

How metabolism works is a complex story. It's a series of chemical reactions inside your body. These chemical reactions produce energy for your body's functions. We've tried to describe how your metabolism works as simply and clearly as possible.

When you eat, your body starts to digest the food. During this digestion process, the food is broken down into basic elements: protein becomes amino acids, carbs become sugars and fat becomes fatty acids. Once your body has made these basic elements, it absorbs them into your bloodstream. Through your bloodstream, they are transported to the cells in your body.

When the basic elements arrive at your cells, they're broken down further in a process called 'cellular respiration'. This process produces 'adenosine triphosphate' (ATP), a complicated name for the most important energy source in your body. Your body needs oxygen for this whole process to happen. The process also produces carbon dioxide as a by-product. You breathe this out again. Once the ATP has been made, it's used to support your body's functions. From basic functions to physical activities such as exercise.

THESE FACTORS INFLUENCE CALORIE BURNING

Your body doesn't convert all calories into energy. Some calories are used to make protein and other molecules. Do you take in too many calories in a day? Then your body converts this into fat. The number of calories your body burns depends on various factors.

• Your weight and body composition: If you weigh more, you generally burn more calories, even at rest. This is because your body needs more energy to function. People with muscle mass also burn more calories than people with a lower muscle percentage, because muscle uses more energy than fat.

• Your age: As you get older, your metabolism generally slows down, which means you burn fewer calories and less fat.

• Your sex: Men generally have a higher metabolism than women, partly because they often have more muscle mass.

• Your activity level: The more active you are, the more calories you burn.

START YOUR REDUCED-CALORIE DIET WITH SPORTMEALS

By the time you read this paragraph, you've taken in all the important information about calories. With all this new knowledge, our question is: will you start a reduced-calorie diet?

We understand that this isn't easy. A diet takes a lot of perseverance and motivation. At SportMeals, we're happy to give you a hand!

With the carefully composed meals from SportMeals, you know exactly how many calories are in your food. Whether your goal is to lose weight or to build muscle, we have a tasty ready-made meal for every goal. Reach your goals with the support of SportMeals. Because together we get further!