Debunking the Calorie Myth
The low-calorie approach to shaping up is based on a flawed model that ignores the basics of the human metabolism. Not only is this approach unworkable, but it can lead to yo-yo dieting and long term weight gain.
The Boiler Metaphor
Nutritionists tend to represent the body like a boiler that burns energy, in the form of calories. If the calories being consumed exceeds the calories being burned by the body then the excess will be stored as fat and the person gains weight. However this simplistic model ignores the way that the body uses calories. You'll find that fat or obese people generally don't eat more calories than slim people. You may even know somebody that can seem to eat as much as they want and never seems to put on weight.
The Survival Instinct
Anybody who has tried a low-calorie diet will have found that there is an initial period of fast weight loss. That is because the body is used to receiving a certain number of calories, and when this decreases, the body uses up some body fat to make up the energy deficit. But this is usually followed fairly quickly by a weight loss plateau and nothing seems to get the scales moving lower.
In response to receiving less food the body slows down it's energy output so it won't have to use it's fat reserves for energy in the future. The body's resting metabolism can reduce by as much as 50%. So the low-calorie diet actually slows down the metabolism, leaving that person open to fast weight gain once they resume their regular calorie intake.
A Formula for Obesity
The low-calorie approach to weight loss has become so ingrained in our culture that it is not questioned by the majority, despite it's general unworkability. Weight gain and obesity statistics show that this approach is not achieving results. A method that lowers metabolism can only result in future weight gain and the yo-yo dieting effect. This approach can also lead to an impaired immune system and lowered energy levels.
The best approach is a high protein, nutrient dense diet without all the "empty" calories.