What is a calorie and why do you need to know?

Updated: Dec 15, 2019

A calorie is basically the amount of energy that a particular food or drink item contains. Our bodies need energy to live and use the calories in the food and drinks that we consume for this. However, if we eat more calories than our body needs during a day, we will have some left over. These excess calories will be stored as body fat and if we continue to do this every day, we will inevitably increase the amount of body fat we carry as well as putting on weight at the same time.


As a guide, an average man needs around 2,500 calories a day to maintain a healthy body weight. For an average woman, that figure is around 2,000 calories a day.

These figures are only approximate though, and can vary depending on age, size and levels of physical activity, among other things. To maintain a stable weight, the energy we put into our bodies should be the same as the energy we use through normal bodily functions and physical activity.


An important part of a healthy diet is balancing the energy you put into your body with the energy you use. For example, the more physical activity we do, the more energy we use. So, if you’re thinking of starting a new fitness regime you need to bear in mind that your body will be burning more calories than before and you may feel hungrier than normal. However, it’s really important that you don’t deal with that hunger by having an extra doughnut or cake, but instead give your body the right type of fuel it needs to keep exercising. The types of calorie you eat can have a big impact on your body, health and fitness.


How to check calories in the food you buy and eat


It’s not easy understanding the calorie and nutritional content written on food labels, but it’s useful to have an idea of some of the basics.


Food labels are full of information including calories, kcal and kj, as well as lots of other nutrients, minerals and vitamins. This can be really confusing and we will cover it in more detail in a later blog for those of you who are interested in knowing more. For now, just be aware that calories and kcal are effectively the same thing, and unless you’re studying to become a dietitian or nutritionist, you don’t need to know any more!


The important thing to remember is that everything you eat (well, almost everything) contains calories. When you exercise, your body burns calories and if you burn more calories than you eat, you will lose weight.


Yo-Yo Diets

A healthy amount of weight to lose would be around 1-2 lbs per week. You don’t really want to be losing any more than this otherwise the likelihood is it will only be a temporary loss and will return again later, and normally add a bit extra as well. This is because if you lose too much weight too fast, your body will start to think that you are going into a form of starvation and will try to store energy in case you stop eating completely. Then, after a few weeks of dieting, you start to eat more calories again but your body will continue to store some of this away for safe keeping instead of burning it off, just in case you decide to embark on another diet. This generally results in the weight you initially lost coming back and bringing some friends with it too! It is sadly, not uncommon for people to go from one diet to another, losing weight and then regaining it over and over again which inevitably results in them actually weighing more than when they started. This is why it is called a “Yo-Yo” diet.


A healthy way to lose weight


To lose 1 lb in weight over a week, you would need to burn off around 3,500 calories more than you consume. To do this, you could either reduce your daily intake by 500 calories a day or increase your exercise regime so that you burn off an extra 500 calories per day. A much better method would be to reduce your daily intake slightly and increase your daily exercise. Even better still would be to look at the types of food you eat and make some healthy changes so that you still consume enough food to keep you full, and energised but still reducing your calorie intake.


Here are two examples to demonstrate this point. One picture shows half of a snickers bar (40g) and the other shows a plate of pasta (145g). Which would fill you up more and which would keep you full for longer? Would it surprise you to learn that both plates contain the same amount of calories (roughly 200)?

So, in summary – a calorie is a measurement of energy in the food and drinks we consume. Our bodies use these calories as energy so it is important not to consume more than we burn.


Eating the right types of food during the day can help you stay focussed and concentrate more. Eating the correct foods before and after exercise is also really important and something we will discuss in a later blog.


If you are feeling ready to take the next step and start adding some exercise to your daily regime, we would love for you to join us at “Get Fit Today”.


Please get in touch if you have any questions.



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