Distinguishing between calories (small c) and Calories (Capital C) can be a little tricky and somewhat confusing. And the fact that some countries and therefore food labels express a particular food's energy measurement in joules just adds to that confusion. But fret not, below is a simple guide ...

In the world of science a calorie (lower case ‘c’) is a small unit of energy, so small in fact that a biscuit can contain thousands of them. In the early 1900’s a man named Edward Atwater began experiments into the science of food and diet. He put together the calorie system for measuring food.

1 calorie is the amount of energy (heat) required to raise 1g of water 1 degree celsius. One thousand of these units is expressed as one kilo calorie (1 kcal) so accordingly this is the amount of energy that it takes to heat 1kg of water by 1 degree celsius.

In the nutrition world 1,000 calories (1kcal) is expressed as 1 Calorie (upper case ‘C’ although it is often written with a lower case ‘c’ which can be confusing). To add to that confusion food nutrition and exercise apps often interchange these terms. So if your app is telling you that you have expended 228 cals during a brisk 30 minute walk, you have actually burnt off 228 Cal. Incidentally a normal size mars bar is 228 Calories (or 228 kcal).

You have also probably seen energy expressed as kilojoules (kJ) on some food packaging. Some countries have adopted this unit of measure in favour of the older Calorie unit. Australia switched to kilojoules over 40 years ago. The conversion between the two units is as follows:

1 joule = 0.24cal   1cal = 4.2j   So that same 228 Cal in a Mars bar = 957.6 kj

CALORIES IN FOOD

The different individual food groups within our diet contain varying levels of energy. For every gram of the following macronutrients and alcohol you get the associated amount of energy:

1g fat = 9 Cals   1g alcohol = 7 Cals   1g protein = 4 Cals   1g carbohydrate = 4 Cals

If you are ‘dieting’ and counting calories there are many diets available that are proponents of either low fat high carb, or low carb high fat or no animal protein or no dairy products etc., the list goes on. So be sure to follow a ‘diet’ that leads to healthy weight loss.

Food for thought: carbohydrates are the only food group that we don’t need to obtain from our diet and that fats and protein are essential for structures, hormones, cells etc within our bodies. In fact your brain is 60% fat!!

Andy