February 7th, 2013
Eat less calories, exercise worth ‘x’ calories, burn calories, ‘x’ calories worth of nutrition, etc. We heard and read this so many times yet how many of us really know what it means? Those of you who think it might have something to do with energy, wow; you are in a minority.
Concept of Calories
Technically, a calorie is that amount of energy that is required to raise the temperature of one gram of water by one degree. To give you an idea of how much energy this is, if you were to put one gram of water that is at room temperature in a glass test tube and hold it with your hand, the temperature of the water would rise by one degree in just a few seconds which tells you that one calorie is not an awful lot of energy. For this reason, the calorie you see mentioned on a food packet is actually kilocalories i.e. in thousands of calories. The same applies to raw food. A gram of protein is 4 kilocalories.
So, a pack of food that contains (say) 200 calories is actually 200 kilocalories i.e. 200,000 calories. Similarly, if you have burnt 100 calories on a run, you have actually burnt 100,000 calories!
However, if everything were to labelled in hundreds of thousands of calories imagine how complicated things would be and how much additional space and therefore packing would be required. Just as we write 1 mile and not 63,360 inches, so too, industry adopted the kilocalorie standard when referring to calories in food.
Coming back to calories, the concept of calories therefore, is the transfer of energy from one object to another or from one state to another.
Why do we need calories?
We need calories because nothing, absolutely nothing in this universe happens without transfer of energy. Even when we sleep, we consume energy (thank heavens for that or we’d all be obese). Breathing consumes energy, our hearts pumping blood requires energy, our lungs pumping air requires energy, to think you require lots of energy, our kidneys filtering the liquids we drank needs energy, digestion requires energy and so on… you get the picture.
How do calories work?
When we eat anything, the food is digested and converted into glucose and stored in the blood stream. Next, the pancreas produces and releases insulin which reacts with the glucose and converts it into energy for instant use. Unused glucose is converted into fat for storage.
Therefore, our body is like one giant, super-efficient battery. There’s ready energy available for instant use and if more is required, insulin is released and glucose is converted into energy. If there is no more glucose available in the blood stream then small quantities of available fat is broken down and converted into energy.
Calories work by energy transformation. Remember the concept of calorie? – Transfer of energy from one object to another or from one state to another. Our body is one big energy transformation machine.
How to calculate calories
We are going to answer this question in relation to the calories required by our body on a daily basis and not in relation to converting matter into energy in a laboratory.
Our body requires a certain minimum quantity of energy (sleeping, thinking, moving about etc.) Depending on the height, weight, age, gender and ethnicity of person, this minimum varies between 1,500 to 2,200 kilocalories per day. People who are very active would obviously require more calories.
To make matters simple, there are a large number of websites that help you calculate calories of anything you have consumed. You can even calculate calories of any physical activity you do. Use these websites to measure the calories in the food and drink you’ve consumed or calculate calories you’ve burnt through your physical activity.