A Calorie with a capital C, is also known as a kilocalorie, or kcal. Nutritional Facts labels in the United States use the "Calorie" label, while in most other parts of the world they are labelled as "kcal". In many other countries an alternate measure of energy, the kilojoule or kJ, is also listed on the label. 1 kcal = 4.1868 kJ


A calorie is a single unit of energy. Heat energy to be more specific. You get calories from the food you eat, and then you burn them by doing stuff, like jogging or sleeping, or just about anything. Ever found yourself reading one of those Nutrition Facts labels? And, upon spotting the "based on a 2,000 calorie diet" statement, wondering how many calories there should be in your diet? Well, this is how you can find out:

Approximate Method:

Extremely Inactive: Activity Level = 12
Light Activity: Activity Level = 15
Moderately Active: Activity Level = 20

The activity level is how many calories you need per pound of body weight, so:

(your weight) x (activity level) = (approximate calories required/day)

Scientific Method:

Find your weight in kilograms:

(your weight in pounds) / 2.2 = (your weight in kilograms)

Basal metabolism is the energy you need just to stay alive.
Determine your basal metabolism needs:

Females: (weight in kg.) x 22 = (basal calories required/day)
Males: (weight in kg.) x 24 = (basal calories required/day)

Find the amount of calories required for your usual activities:

Very Sedentary: Activity Level = 20%
Sedentary: Activity Level = 30%
Moderately Active: Activity Level = 40%
Very Active: Activity Level = 50%

(basal calories/day) x (activity level) = (activity calories required/day)

Find your total caloric needs:

(basal calories/day) + (activity calories/day) = (calories required/day)

Add 10% for energy needed for digestion and nutrient absorption:

(calories required/day) + (10% of calories required/day) = (total calories required/day)

So, now you know how many calories should be in your diet. Or do you. See, the number you got is the number of calories you need if you mantain your activity level exactly, and don't want to lose or gain any weight. If you want to gain weight, you should get more calories, and be sure to exercise. If you don't exercise when you're gaining weight, then you gain fat, not muscle.

If you want to lose weight, eat less calories, but still be sure to exercise. If you don't, you'll lose muscle, not fat. Also, be sure you don't gain or lose more than 1-2 pounds a week, or else you could be causing serious damage. After you reach your weight goal, calculate your caloric intake. If you keep your caloric intake and activity level steady, you shouldn't gain or lose any weight.

Also, if you know your caloric intake, then you can calculate how much of other things you need in a day, like carbohydrates (carbs). You'll notice that, next to each thing on a Nutrition Facts label, there's a percentage. This percentage tells you what percent of your needed daily stuff one serving contains. If your caloric intake is 2,000 calories/day, then it's real easy for you. Everything on the label will fit you exactly. If the carbs say 10%, then that's 10% of the carbs you need in a day. If you're caloric intake is, say, 1,500 calories/day, you have to multiply everything by 0.75, since 1,500 is 75% of 2,000, which is what the facts are based on.

Another hint: the Nutrition Facts label tells you exactly how many calories there are in a serving, right? Wrong! It's approximate. To find the exact number, multiply the grams of fat by 9, protein by 4, and carbs by 4. Add them all together. That is exactly how many calories there are in one serving. Cool, eh?

A unit of measurement defined as 4.184 absolute joules, or the amount of energy it takes to raise the temperature of one gram of water from 15 to 16 degrees Celsius (or 1/100th the amount of energy needed to raise the temperature of one gram of water at one atmosphere pressure from 0 degrees C to 100 degrees C); food calories are actually equal to 1,000 calories (1 food calorie = 1 kilocalorie).

Cal"o*rie (?), n. [F., fr. L. calor heat.] Physics

The unit of heat according to the Frensc standard; the amount of heat requires to raise the temperature of one kilogram (sometimes, one gram) of water one degree centigrade, or from 0 to 1. Compfre the English standart unit. Foot pound.


© Webster 1913.

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