What are Calories ?
Calories are the most common energy unit in the food industry.
1 calorie (aka small calorie – cal) is the amount of energy required to increase with one degree Celsius the temperature of one gram of water.
1 KiloCalorie (aka large calorie – Kcal) is equal with 1000 cal and is the amount of energy required to increase with one degree Celsius the temperature of one Kg (1000 grams) of water.
In some areas, you can see on the food labels both Kjoules and Kcalories
1 calorie = 4.18 joules.
1 joule = 0.239005736 calories
According to Medi lexicon’s medical dictionary, a Calorie is “a unit of heat content or energy. The amount of heat necessary to raise 1 g of water from 14.5-15.5°C (small calorie). A calorie is being replaced by joule, the SI unit equal to 0.239 calories.”
On the food labels, the calories are, actually, Kcal. So, a 350 calorie chocolate bar has in fact 350,000 calories.
The number of calories contained by food let us know how much potential energy they posses.
Below are the calorific values of the main components of the food we consume, these values are those that are taken into consideration for food labels:
1 gram of carbohydrates contains 4 calories
1 gram of protein contains 4 calories
1 gram of fat contains 9 calories
1 gram of alcohol contains 7 calories.
How many calories do we need each day ?
Each body is different and has its own energy consumption, so it’s impossible to define a number of calories that we have to take in each day, applicable for all of us.
Our calorific consumption depends on several factors, including our overall general health, physical activity demands, sex, weight, height, and shape. A 6ft tall, 20-year-old professional soccer player needs much more calories each day than a 5ft 2ins sedentary woman aged 75.
Health authorities around the world find it hard to agree on how many calories their citizens should ideally consume. The US government says the average man requires about 2,700 calories per day and the average woman about 2,200, while the NHS (National Health Service), UK, says it should be 2,500 for mans and 2,000 for womans.
The FAO (Food and Agriculture Organization) of the United Nations says the average adult should consume no less than 1,800 calories per day.