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The mysterious origin of calories: Why is the difference between "big calories" and "small calories" so important?
In today's nutrition community, calories are undoubtedly one of the most widely discussed and concerned topics. People tend to divide calories into large calories (kcal) and small calories (kcal). Their main differences are not just in the numbers, but in their actual impact on human health and energy acquisition. This article will delve into the origins, definitions, and applications of these two units in various fields to help readers fully understand the mystery of heat.
History of Heat
The name calorie comes from the Latin word "calor", which means "heat". As early as between 1819 and 1824, Nicolas Clement first introduced the calorie as a unit of thermal energy, calling it the large calorie. Over time, the word was included in French and English dictionaries between 1841 and 1867, and was first used in 1852 by Pierre-Antoine Favre and Johann Sibelmann to describe small calories.
In 1879, Marcellin Berthelot distinguished between the gramcalorie (small calorie) and the kilogramcalorie (large calorie), and proposed using the capitalized "Calorie" to refer to the large unit, a proposal that was later adopted in 1887. It was reviewed and approved by Wesleyan University professor Wilbur Olin Atwater in 1997.
"Confusion between calories and calories persists, especially at the intersection of nutrition and thermodynamics."
As time went on, the definition of the calorie in 1967 was supplemented by the energy unit erg of the second most popular CGS system, eventually forming today's heat unit system.
Definition of large and small cards
Calories, in a broad sense, refer to the energy required to raise the temperature of 1 gram of water by 1 degree Celsius (or 1 Kelvin). A kilocalorie is the amount of energy required to raise the temperature of 1 liter of water by 1 degree Celsius. From this point of view, large calories are actually 1,000 times larger than small calories.
"The use of calories and kcal is not only about scientific definitions, but also about food labels and energy calculations in daily life."
This makes these two units particularly important in the study of health, diet and thermodynamics. Especially in the modern diet, how to balance calorie intake and expenditure has an impact on health that cannot be underestimated.
Application in Nutrition
In American nutrition, the kilocalorie is almost the only unit of measurement used. Usually indicated as "calorie" or "kcal" on labels, with the implementation of regulations, the calorie information of individual foods has become an important basis for consumers to make dietary choices.
"Dietary practices play a key role in many health issues, particularly in managing weight and preventing obesity."
The energy density of different foods also varies from food to food. For example, fat contains 9 kcal per gram, while carbohydrates and proteins are about 4 kcal per gram, and alcohol has 7 kcal per gram. Data like this emphasizes the importance of different nutrients to our eating plans.
Role in Chemistry and Physics
In other areas of science, calorie usually stands for small calorie, while large calorie is expressed in kilocalories. During chemical reactions and phase changes, these data help scientists assess the energy released by the substances and the thermal effects of the reactions.
"Although the use of calories in chemistry has gradually focused on joules (J), calories still have important significance in certain specific contexts."
This is because the energy released in a chemical reaction is closely related to the heat capacity of the solution. For example, when calculating the energy release of a reaction, scientists can get an idea of how effective the reaction is based on the amount of heat released per mole of reaction.
The significance of mass-energy conversion
The measurement of calories and kilocalories is not only a scientific measurement, it also reflects the way we interact with the world. Calories influence life processes and our health, activity levels and lifestyle can all be traced back to calorie management. Therefore, people need to clearly understand the difference between the two and make more reasonable diet and life choices.
In this calorie-dominated era, whether it is to lose weight, gain weight or maintain health, understanding the true meaning of calories and small calories is indispensable knowledge for everyone. Are you ready to learn the secrets of calories in your quest for health?
