“How many calories should you eat a day?” is a trick question and we have to take many factors into consideration for example, body composition, gender, age, weight and your daily calorie intake.
Before we discuss calories, let us define the word metabolism. This is a term used to describe how nutritional materials are oxidized in the cells of the body to produce energy in the form of heat.
This heat may be used immediately to do the work for example, synthesize the new cell form amino acids, or it may be stored in a chemical form as adinosin triphosphate(ATP).
The heat is produced to maintain the body temperature at an acceptable level(37 degrees). The excess heat is disposed of through the skin and body secretions.
A calorie is defined as the amount of heat required to raise the temperature of 1 litre of water per centigrade degree. Calorie is an expression of the nutritional value of protein, carbohydrates and fats eaten in a given meal expressed in calories per gram.
It is estimated that 1 gram of carbohydrate provide 4 calories, 1 gram of proteins provide 4 calories and 1 gram of fats provide 9 calories.
The minimum energy requirement of per day is described as the basal metabolic rate (BMR). This is the rate at which the sum of metabolic activity take place when an individual is at rest at is starving for at least 12 hours- after the last meal has been digested and absorbed.
The basal metabolic rate is higher in men than in women, therefore men require more energy foods. In normal life, most of the basal energy requirement is used during the 8 hours of sleep because during sleep the metabolism is always above normal basal level.
This means that the normal diet should provide more calories to make up for the period of 24 hours.Therefore the more active an individual becomes, the more energy he requires. So the amount of calories required per day may vary from an individual.
However, health authorities have set up a baseline figure for men and female, 1800 and 1200 calories respectively.
The calorie intake calculator is used to give a more accurate daily calorie intake based on the following factors:
Your body composition
Daily activity levels
Age
Gender
Weight
Height
When all these are factored in, a total calorie level will be calculated and provide your daily calorie intake. This is all I can advise in simple terms. For more details, do a bit of research or see your local nutritionist. Good luck!