As experts say, a calorie is not always a calorie. True enough, as there are two types of calorie, the small and large calorie, which both vary in magnitude. The former is the gram-calorie used in physics and chemistry, while the latter is the nutritional calorie you see on diet books and food labels.
A small calorie (cal) is the amount of energy that is needed to raise the temperature of 1g (one gram) of water by 1° Celsius. The required energy is also known as the specific heat of the water. This is why a calorie is referred to as the way to calculate energy by using heat.
In 1925, calories were initially defined in physics and chemistry as joules. They serve as a unit of measurement that states the amount of work required to push one newton across one meter. Today, it is still used in the SI system as a unit of energy. One calorie is equal to 4.18 joules.
The large calorie, or also known as the kilocalorie (kcal) is the amount of energy that is needed to raise the temperature of 1kg (one kilogram) of water by 1° degree Celsius. It is used on food labels and diet books as a unit of measurement of the amount of energy available on a specific type of food.
However, while it is regarded as kilocalorie (kcal), it is often placed on nutritional labels as Calories with an uppercase C. They differ from the calories used scientifically because, in reality, they are actually kilocalories. Thus, the uppercase C to provide a distinction between the two. That way, it will be easier to note that when you see Calories, it is referring to kilocalories.
A Calorie is made up of 1,000 small calories. If you consume a 300-Calorie chocolate bar, it actually contains 300,000 small calories.
Certain nations, however, like Australia and some countries in Europe, use kilojoules instead of Calories on their diet books and nutritional labels. Before, the means of calculating kilocalories were through a bomb calorimeter. In this process, food was actually burnt in its entirety, to get an estimation of how much temperature increased during the burning process.
Now, calories are measured using the Atwater system. It depends on the energy stored in each component of fat, protein, and carbohydrate that builds up any food item. Carbohydrates and proteins both have around four Calories each gram, while fats have nine Calories each gram.
In terms of nutrition, Calories play a significant role in terms of losing and gaining weight. A person who consumes less than the required nutritional calories their body needs will shed weight, while those who consume ends up gaining weight. This is the reason why you often see health-conscious individuals taking note of their dietary calorie intake each day.
There are various recommendations on how many Calories an individual needs to have each day. Many weight loss programs focus on decreasing Calorie intake to reduce weight. Meanwhile, those people tend to be more active, such as athletes, will require higher Calorie requirements than those who are not inclined to do vigorous activities.
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