All successful weight loss programs rely on one common denominator; calorie restriction.

What is calorie restriction? Calorie restriction is an effort to reduce the amount of calories one consumes in order for the body to achieve a negative energy balance. This is simply a person reducing food consumption to the point that they are burning more energy than they are consuming. The body is then forced to use stored fuel (muscle tissue, glycogen and body fat) in order to survive. The burning of these stored fuels is cause of the weight loss phenomenon.

How does a person achieve this negative energy balance through calorie restriction? First a person must have an idea on what a calorie is. A calorie is a measure of heat. Food is the fuel our body needs to generate heat. If the body is not getting enough fuel from food consumption then the fuel must be found elsewhere. That fuel is found in our body fat.

The best analogy for this process is gasoline and an automobile. Cars run on gasoline. Without gasoline, a car is useless. We drive our car and fill up with gasoline when we are getting low on fuel.

What would happen if we put 18 gallons on gas in our car if we only burned 16 gallons? We would have extra gas left over. That extra gas has to go somewhere so it goes into storage for when we only have 14 gallons available but we need 16 gallons.

What would happen if we never tapped into our gas reserves? The surplus would keep growing and growing causing a need for larger storage tanks.

The human body works in the exact same way. The surplus fuel (food) is turned into stored energy (body fat) and the only way to reduce how much fuel is stored in reserve is to limit new consumption of fuel (food). This is the only way that the human body can body fat. A caloric deficit must be established so stored energy (body fat) can be burned to keep us alive.

How is a calorie deficit achieved? The simplest answer is to eat a fewer number of calories then it takes to fuel your basal metabolic rate. The BMR (basal metabolic rate) is the measure of energy a person needs to subsist. People can figure out their BMR by using any of the numerous BMR calculators that can be found online.

Once the BMR is calculated a person can then have a goal to shot for. If the BMR is 2500 calories a day, they a person should shoot to try to eat fewer the 2500 calories a day for a consistent period of time.

How can a person effectively create a caloric deficit? Part 2 of this article will address this issue.

W.S. Evans (Bill) is one of the millions of people who have battled a life long weight problem. Bill has a passion for helping others battle their weight problems by sharing what he has learned with his struggles with obesity. Bill's struggle can be viewed on his blog called "My next 60 pounds". Bill's blog can be found at http://billgetsfit.blogspot.com.