 CALORIES:  We talk about them constantly and for many of us it is the first thing we look at on a nutrition label. But how much do we actually know about calories? What are they?

Calorie: 1. Either of two units of heat energy. 2. The energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.1868 joules).

Technically 1 “food calorie” is actually 1 KCal as in 1,000 calories.

How many (kilo)calories do I burn?

The Harris-Benedict Equation for Basal Energy Expenditure (BEE) is commonly used to calculate energy requirements based on sex, height, weight and age.

W = weight in kilograms H = height in centimeters A = age in years

Men: BEE = 66.5 + 13.8(W) + 5.0(H) – 6.8(A)

Women: BEE = 655.1 + 9.6(W) + 1.9(H) – 4.7(A)

Your BEE is basically the amount of calories you would need if you were a couch potato and sat on your ass all day.  If you are a normal person, your BEE will need to be multiplied by a factor of 1.2-1.5 to account for extra calories burned during physical activity. A factor of 1.2 represents an average amount of activity, whereas 1.5 would be a very high amount of activity.

If doing math is too much effort, I recommend using this calculator:

How many should I eat?

To maintain weight you eat the same number of calories as you burn.

To gain weight you eat more than your body burns.

If you are trying to lose weight you eat less.

1 lb. of fat contains 3,500 calories. To lose 1 lb. per week you should have a daily deficit of around 500 calories. While body weight lost is not pure fat, this can still be used as a benchmark to approximate the caloric deficit needed to lose a certain amount of weight. This does not factor in fluctuations such as water weight. Keep in mind, your body becomes more resistant to caloric restrictions the leaner you become and you will need to be less restrictive than you would at a higher weight.

Calories from Energy Nutrients

Protein: 4 cal./ gram

Carbohydrates: 4 cal./ gram

Fat: 9 cal./ gram

Alcohol: 7 cal./gram.