Definition of calories
How many calories are needed per day? How many calories should I eat per day? These are common questions which are asked by a lot of people.
First of all, let’s define calories. Calories were first defined by a French chemist, Nicolas Clement, back in 1824. Calories are basically, energy measurement units which are used to gauge the amount of energy stored in foods. Actually, the word “calorie” is an abbreviation of “kilocalories,” but because “calories” have been used for so long, nobody uses “kilocalories.”
In science, calories are considered an outdated way to measure food energy. Normally, scientists will use kilojoules instead. A calorie is equivalent to 4.2 kilojoules. So let’s say you want to find out how many calories are in 4200 kilojoules. Just divide that 4200 kilojoules, and you get 1000 calories. 4200 kilojoules = 1000 calories.
There are also 2 “versions” for calorie definition – the kilogram calorie and the gram calorie. The kilogram calorie is defined as the amount of heat that is able to raise the temperature of 1 kilogram of water by 1 degree Celsius, while the gram calorie is the amount of heat required to raise the temperature of 1 gram of water by 1 degree Celsius. The kilogram calorie is by far the accepted “version” and you might see this on food labels termed as kcal.
How many calories are needed per day?
There is no absolute hard and fast rule pertaining to how many calories are needed each day, or how many calories you need to eat to lose weight. Each human being is different, and therefore, their metabolic rates differ. Also your level of physical activity per day is highly important.
Metabolic rate has a lot to do with how your body determines how much fat to store and how much fat to burn. Some people can eat all the foods they desire and never put on so much as a couple of pounds, while others seem jinxed by touching even the smallest pie or cake. It appears that where your calories are coming from is more important than the actual total intake because of the way the body treats food.
A Useful Tip:
A common practice is to not allow more than 30% of your daily calories to come from fats. There is a 9-4-4 formula that is easy to memorize.
- 1 gram of fat = 9 calories
- 1 gram of protein = 4 calories
- 1 gram of carbohydrate = 4 calories
To know whether your intake of calories for today (from fat) is more than 30%, divide the calories calculated from the fat content by the total number of calories you took in today.
The simple calorie calculator (at the top of this page) gives a rough estimate of how much calories you need daily, based on gender, height, and weight. In general, most adults need around 2000 calories per day, although like I mentioned above, it varies from individual to individual. A successful weight maintenance program will always incorporate an active lifestyle combined with healthy eating.