This is from a book titled ' Power Eating' by Susan Kleiner
page 86- 87
Antifat Diet Strategies
The old-fashioned way of figuring out how many calories you should eat to lose weight is to just chop off 500 to 1,000 calories from your current deit. One pound (.5 kilogram) of fat is equivalent to 3,500 calories. According to the laws of the thermodynamics, if you feed yourself 500 calories fewer than you need each day for seven days, theoretically you should lose 1 pound (.5 kilogram) at the end of the week. Double that amount and you should lose 2 pounds ( 1 kilogram). But dietitians have known for years that it never works this way, and this strategy becomes more frustrating as the weeks of dieting wear on.
At Georgia State University, Dr. Dan Benardot wondered why these seemingly clear laws of physics don't hold true within the human body. His research has shown that once food enters the biological system of the body, there are more variables at work than the simple number of calories that are given off by a pound of fat when measured directly in a science lab. The human body is a living organism, and the drive for survival allows the rules of the system to change based on thousands of years of adaptation to the environment. Dr. Bernardot tested two groups of female gymnasts and runners: One group ate a diet of 500 fewer calories than they needed to maintain their weight each day, and the other group ate 300 fewer calories. What he found was astounding: The group that ate 300 fewer calories had a lower percentage of body fat than the group that actually ate less food. His theory is that when too few calories are eaten, resting energy expenditure (REE) slows down to meet the energy available to the body.
The ability of the body to slow metabolic rate to meet available energy has long been understood by scientists. Called starvation adaptation, it is induced in extreme circumstances of famine to allow the body to survive far longer than would be predicted based on normal metabolic rate of energy use. Dr. Bernardot is proposing for the first time than even under mild states of energy deficit, energy use slows down. There is no benefit to eating far fewer calories than your body needs. In fact, he calls a 300-calorie deficit the ideal metabolic window for women to lose the most amount of fat in the shortest amount of time.
So forget low-calorie dieting. When you reduce your caloric intake by 300 calories (women) or 400 calories (men), you can keep your metabolic rate high enough to continue to burn fat at a good clip. Additionally, you want to have enough energy to perform at peak levels both physically and mentally. Here's how to eat to give youself the best chance at losing fat and saving muscle.
