Counting calories can be a laborious task but is something you should learn to do if you are to become educated on the best ways to lose weight, get fit and stay slim.

The simple mathematics of it is, if you eat more calories than you burn off, you will put on weight. If the reverse is true and you burn more calories than you consume, then you will lose weight.

What is a calorie?

A calorie is a unit of energy. We tend to associate calories with food, but they apply to anything containing energy. For example, a gallon (about 4 liters) of petrol contains about 31,000,000 calories.

Specifically, a calorie is the amount of energy, or heat, it takes to raise the temperature of 1 gram of water 1 degree Celsius (1.8 degrees Fahrenheit). One calorie is equal to 4.184 joules, a common unit of energy used in the physical sciences.

Most of us think of calories in relation to food, as in "This biscuit has 100 calories." It turns out that the calories on a food package are actually kilocalories (1,000 calories = 1 kilocalorie). The word is sometimes capitalized to show the difference, but usually not. A food calorie contains 4,184 joules. A biscuit containing 100 food calories contains 100,000 regular calories, or 200 kilocalories. A gallon of petrol contains 31,000 kilocalories.

The same applies to exercise -- when a fitness chart says you burn about 100 calories for every mile you jog, it means 100 kilocalories. For the duration of this article, when we say "calorie," we mean "kilocalorie."

So now the science is out of the way, what should you do with this information? Well, get to know how many calories the food you eat contains. Almost every piece of food packaging contains this information.

Do a simple tot up of your day's intake to see how you got on. The good news is that if you are a woman, just to get by each day, you need to consume approximately 2000 calories. If you are a man you need to consume 2500 calories each day.

So how to you use this informaiton to lose weight? To lose one pound of fat, you need to burn 3000 more calories than were consumed. Sounds like a lot doesn't it? Well, if you burned 600 calories each day more than you consume, in 5 days you could lose 1lb.