eskindian's Journal, 24 March 2011

High-protein, low-carbohydrate diets have been widely promoted in recent years as an effective approach to losing weight. These diets generally recommend dieters receive 30% to 50% of their total calories from protein. By comparison, the American Heart Association, the National Cholesterol Education Program, and the American Cancer Society all recommend a diet in which a smaller percentage of calories are derived from protein (nutrients essential to the building, maintenance, and repair of tissues in the body).

The Atkins diet is an example of a low-carb diet.

How Do Low-Carb Diets Work?

By restricting carbohydrates drastically to a mere fraction of that found in the typical American diet, the body goes into a different metabolic state called ketosis, whereby it burns its own fat for fuel. Normally the body burns carbohydrates for fuel -- this is the main source of fuel for your brain, heart ,and many other organs. A person in ketosis is getting energy from ketones, little carbon fragments that are the fuel created by the breakdown of fat stores. When the body is in ketosis, you tend to feel less hungry, and thus you're likely to eat less than you might otherwise. However, ketosis can also cause health problems, such as kidney failure (see below).

As a result, your body changes from a carbohydrate-burning engine into a fat-burning engine. So instead of relying on the carbohydrate-rich items you might typically consume for energy, and leaving your fat stores just where they were before (alas, the hips, belly, and thighs), your fat stores become a primary energy source. The purported result is weight loss.