All About Calories
Calories. You’ve heard those three little syllables before. Anytime anybody is on TV hocking food at you, they’re promoting their products as “low in calories”. Talking heads on daytime talk shows advise you to “avoid high calorie foods” and “keep track of your calories”. In a culture obsessed with looking good, “calorie” is a dirty word. But have you ever wondered why?
Answering the question of why the word “calorie” is so prevalent requires us to first define what a “calorie” is. From there, it’s pretty easy to explain why calories get so much attention from the health-conscious.
What is a “Calorie”?
In the simplest terms, calorie is a measure of energy. More specifically, a calorie is the amount of energy it takes to raise the temperature of 1 gram of water 1 degree Celsius. In food, the calorie is a measure of the potential energy stored therein. This energy is eaten, processed by the body, and used to fuel the body as it works.
The caloric information found on food package is actually a measure of kilocalories. One kilocalorie is 1,000 calories. Thus, a bottle of Vanilla Coke that says it contains 260 calories on the label actually contains 260,000 calories. Don’t worry, though. The calorie count works the same way for exercise. For example if someone says that running for 15 minutes burns 100 calories, they mean it burns 100,000 calories.
Why Calories Matter
Now that we’ve defined what a calorie is, let’s talk a bit about why calories are important. Your body burns energy as it goes through the day. Even if you sit around all day watching cartoons, your body needs energy to keep your heart beating, your lungs working, and your eyes open. You need to get that energy from somewhere, and that where calories come in.
Everything you eat has calories in it. The caloric concentration varies from food to food. Carbohydrates and proteins both contain 4 calories per gram. Alcohol contains 7 calories per gram. Fats are the most calorie rich food, containing 9 calories per gram.
You need calories to sustain your bodily functions and help you do work. Every person has a minimum amount of calories they burn in a day to keep him or her alive and kicking. This is called the Basal Metabolic Rate. You’ll have to take in more calories if you plan on doing any work apart from sitting around. The trouble comes when you take in more calories than you burn in a given day. Any extra calories you take in are stored in your body as fat and being excessively fat leads to serious and sometimes fatal health issues.
Since excess calories are stored as fat, it’s a good idea to know how many calories you need in a day. There are also a few pertinent statistics that will help you to set up your daily calorie budget.
To start with, you need to your Basal Metabolic Rate. There are many online calculators that can quickly give you a number. If you care to do it yourself, here’s the formula:
- For men: BMR = 10*weight + 6.25*height – 5*age+5
- For women: BMR = 10*weight + 6.25*height – 5*age – 161
Once you know your BMR, you need to account for how many calories you need to support your level of activity. The amount of energy you need to intake varies depending how much moving around and work you do. Online calorie calculators like the one at http://www.freedieting.com/tools/calorie_calculator.htm take your activity level into account and assign it a numerical value.
How about some figures? 3500 calories is equal to one pound of fat, therefore if you cut 500 calories a day out of your daily food intake, you can lose pound a week.
Just for fun, let’s apply some stats. Here are a few numbers based on a moderately active, 5 foot 5 inch tall, 135-lb, 35-year-old woman.
- Basal Metabolic Rate: 1310 calories/day
- Total calories needed including exercise: 1801. If she continues to take in this amount of calories, her weight will remain constant. If she takes in more calories than the, the excess calories will be stored as fat.
- Calories needed to lose 1 pound a week: 1301 calories/day