In the last ten years low-carbohydrate diets have gained increased credibility. The basic idea for these diets (first premiered by Dr. Atkins in his 1972 book "Dr. Atkins' Diet Revolution"), is not that all carbohydrates are bad, but that simple carbohydrates like white rice, sugar, bread and pasta should be avoided in order to prevent blood-sugar problems ("insulin resistance"), which can lead to obesity, heart disease, diabetes, etc. Atkins believed that complex carbs like fruits, veggies and whole grains are digested slowly and contribute to good health and weight loss. His most controversial position was that animal fats like eggs, butter and red meat are healthy.
The Obesity Epidemic
Dr. Atkins returned to the scene in 1992 with his "Dr. Atkins' New Diet Revolution." A lot had changed in the 20 years since his first book. Americans were consuming low-fat, high-carb foods but the pounds were piling up. Thirty million Americans have reportedly tried the Atkins diet, and many in fact have experienced significant weight loss, with no harmful effects. The obesity epidemic is ongoing in America: The CDC reports that twice as many Americans (59 million) were obese in 2000 than when Atkins' first book emerged. In recent years there has been a leveling-out effect, but rates of diabetes are rising sharply.
One of the drawbacks of the low-carb diet is that the body's metabolism stubbornly clings on to its weight, resetting itself every time it gets used to a certain amount of calories being consumed. On the traditional Atkins diet, most people reach a point at which they can't lose any more pounds. This has led to a number of nutritionists and trainers suggesting adjusting carbohydrate intake every few days in order to trick the body.
The basic concept of carb cycling is to eat low carb for a certain number of days, then go back to eating higher carb for 1 to 2 days (complex carbs such as beans and whole grains), then back to low carb. Diets can be three days low carb to one day carb, four days low carb to one day carb, or five days low carb to two days carb. The point is to trick the body out of starvation mode, but users get the benefits of a low-carb diet.
More research obviously needs to be done on carb cycling. None of the established diets popular at the moment (Weight Watchers, Atkins, The Zone, South Beach, Paleo) address carb cycling in their literature. It appears to be more of a word-of-mouth phenomenon. The information out there suggests that carb cycling is something to try when you have lost most of the weight you need to lose. It can help you lose the last stubborn weight so that you can meet your weight loss and fitness goals. Don't try it at the start of your diet; you'll do better on a fixed plan.