What are Calories?

A calorie is a measure of energy. It is scientifically described as being the amount of energy required to raise the temperature of one gram by one degree Celsius. Calories of a food can also be recognized as a kilocalorie, or one thousand-calorie unit.

In order for your body to grow, your body is required to have certain amounts of energy, or calories, depending on your age and height. For example, according to the Food and Nutrition Board of the National Research Council, women twenty-five to fifty years of age who are five feet, four inches tall and weigh 138 pounds, have a suggested 2200 calorie intake. For those of different height, weight, age, body size, physical condition, physical activity, and sex, your calorie intake may be different. Teenagers require more calories than full-grown adults do since teen's bodies are still growing and need that extra energy. Also, those who are more active will require more calories than those who are inactive. You gain extra weight when the food you eat provides more calories than your body needs and the excess calories are stored as fats.

The number of calories you need to eat each day is determined by how much energy you need to maintain your lean mass and the internal functions of your body's processes. Since this is true, you are able to check how many calories your body needs by testing your Basal Metabolic Rate (BMR), which is the rate at which your body spends energy for maintenance activities each hour. You can do so by following these instructions taken from "Calories Required | BMR"

"A) Divide your weight by 2.2 ( = your weight in kilograms)

Multiply that number by the BMR factor (1 for a man, .9 for a woman)

Multiply that number by 24 (for hours in a day)

This is your BMR.

B) Add that number to your activity level, which is:

Sedentary = 40-50% of your BMR

Light activity = 55-65% of your BMR

Moderate activity = 65-75% of your BMR

Heavy activity = 75-100% of your BMR

This is your activity level energy requirements.

C) Add the numbers from A and B together.

This is your daily calorie requirement.

You need to eat at least this much to maintain your current body weight.

To lose weight, cut about 500 calories per day (for a 2,000 calorie-per-day diet)."

These calculations will be average estimations. The following factors will increase your BMR; younger age, tall, thin people, pregnant, lean tissue, if you have a fever, stress, temperature of the atmosphere increase and decrease your BMR, and fasting lowers it.

Some foods have more calories than others do; most are mixtures of water, protein, carbohydrates, and fat. The number of calories in a feed depends on how much each of these is present. Proteins and carbohydrates have about four calories per gram while fats have about nine. Water, as your might expect, has no calories. With seven calories per gram, alcohol also increases calories.

Ultimately, the older, more inactive, and those who weigh more are going to have more calories than those who are physically fit.