CALORIES EXPLAINED
The number of people that do not know the definition of a calorie is usually pretty big. This is not a surprise because while we use the term "calories" all day long, we are not usually taught the definition of what a calorie is. So...let's turn on the heat and explain what calories are, and why we used them.
Some people think calories are an actual and physical component of their food they are eating, meaning that if you "open" your food or look into it, you could actually see the calories. Some people think calories are an actual and physical component of their food, yet are too small to be visible. Some people think calories are made of fat or carbs.
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Others think it is a type of energy, yet are not sure what kind of energy are calories. Kilo-calories are also called big calories and abbreviated as "Kcal". Calories are also called small calories and are abbreviated as "cals" or simply written with a non-capital C. Kilo-calories is a unit 1,000 times greater than calories (small calories). Accordingly, 1 kilo-calorie is the same as 1,000 calories.
One kilo-calorie is the amount of heat energy required to increase the temperature of 1,000 grams (1 kilogram; 1 Kg) of air free water by one degree celsius (the equivalent of 1.8 degrees fahrenheit). Thus, if you put 1,000 grams of water (2.2 pounds) in a pot and start heating the water, once the water's temperature goes up by one degree celsius or 1.8 degrees fahrenheit, it means the 1 kilo-calorie of energy has been invested.
One calorie is the amount of heat energy required to increase the temperature of 1 gram of air free water by one degree celsius (the equivalent of 1.8 degrees fahrenheit). Thus, if you put 1 gram of water (a pound divided by 450) in a pot and start heating the water, once the water's temperature goes up by one degree celsius or 1.8 degrees fahrenheit, it means the 1 calorie of energy has been invested.
As part of the metabolism of the body, catabolic reactions are used to breakdown molecules to their chemical components, while releasing energy to the environment. Yet, the catabolism of a molecule itself costs energy, often heat energy. Since we tend to say that energy can change forms, yet never disappear, heat energy is just one way of representing the energetic cost of a process and/or the process' reactions. Accordingly, eating food adds energy to the body as its caloric potential of the food, and digesting the food will require an energetic investment.
As a reminder (explain in one of my other posts) the average person will require about 1,738 kilo-calories (Kcals) just to be alive and at physiological rest for 24 hours straight. At the same time, a small portion of creamer is worth 20- 50 calories per 15 mL (a bit more than half an oz) or one table spoon; A slice of white bread that weighs 30 grams of which 15 grams are carbs will be worth 79 kilo-calories; An average size slice of pizza without any toppings is worth 350-450 kilo-calories; A boiled chicken's egg that weighs 50 grams is worth 75-80 kilocalories; and there are 110 kilo-calories per 150.25 grams (5.3 oz) of potato.
We know how to convert one type of energy to another. We can convert kilo-calories to other types of energy. For example, one kilo-calorie is the same as 4.18 kilo-joules or 4,180 joules; One Watt is the same as 0.859 Kcal per hour.
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