What is a calorie and why are they so important?

So, what actually is a calorie? Most people have heard the term 'calorie' but very few know what a calorie really is and why it is so important that we avoid consuming too many on a daily basis.  

Quite simply: a calorie is a unit of energy. More specifically, it is the heat energy required to raise the temperature of one gram of water by one degree Celsius. It is this potential energy that fuels our bodies, not only during physical activity, but also whilst we are sleeping and resting (Basal Metabolic Rate). Our bodies are essentially energy-hungry machines that require a certain number of calories to keep them functioning healthily.

How do I calculate how many calories I burn daily?

It's pretty simple, really. Our bodies need energy to fuel anything we do and calories give us the energy that we need to do so. The body requires calories not only when you're desperately running to catch a bus, or breaking a sweat in the gym, but also when you feel as though you are doing absolutely...nothing!  

A bit technical, but interesting …

 

Basal metabolism (BMR) is on average the largest component of total caloric expenditure, significantly so in fact (60-70% of all calories consumed fuels basal metabolism). It represents the minimum amount of energy needed to keep your complex body functioning: pumping blood, regulating temperature, turning the cogs of your brain, and so on.

BMR ranges from person to person but you can calculate your personal BMR here. 

Example (A): You are a 35-year-old woman, 5'6" and weight 65 kilos (142 lbs)

Your BMR would equal 1418.4 and you would need to consume this number of calories each day to maintain your weight if you were resting all day. 

But if you decided to go for a run, and burned 500 calories doing so, you would need to consume even more calories:

BMR (1418.4) + Calories burned during run (500) = Total calories burned (1918.4)

The total number of calories that you would need to consume daily would be 1962 to stay at the same weight.

These estimates might not be flawless, but they do give a good idea about the number of calories that you should be consuming daily to maintain a healthy body weight. 

Calories in vs. calories out: getting the balance right!

Potential energy - energy that has been soaked up from sun and stored - is provided by all foods. However, certain foods possess a greater amount of potential energy than others and this is measured through calories. 

Fats, proteins, and carbohydrates are the three 'building-blocks' that make up all foods. Through the digestion process, enzymes in our bodies breakdown food into these components and 'unlock' the energy that they possess.

If you consume more calories than you expend your body has no use for this potential energy and, as a result, it is stored as fat. In contrast, if you expend more calories than you consume you will lose weight as you will need to access the stored energy that your body 'saved for later'. 

Being calorie-conscious doesn't necessarily mean stripping all of the high calorie foods from your diet. Rather, it is all a balance game. Tilting the 'calories consumed' or 'calories burned' scales either way too drastically could impact your health.

Balance is key!

You don't have to follow calories like a slave. Continue to enjoy a wide variety of tasty home cooked food. But having a better understanding of how many calories you are consuming and burning off will help you on the road to a much healthier, happier you.