Lessons from the Low-Carb Diet Craze
What Are Low-Carb Diets?
Low-carbohydrate diets have become the rage in the past few years, but they've actually been around for decades. In 1972, Robert C. Atkins, MD, unveiled his philosophy in The Atkins Diet. Thirty years later, the diet was relaunched with Dr. Atkins' New Diet Revolution.
The essence of the Atkins Diet is weight loss through a series of dietary phases, the first aiming to send the body into benign dietary ketosis, a state in which it starts to burn more fat for energy than it would normally, instead of its preferred source of fuel, glucose -- also known as blood sugar. People following the Atkins' plan restrict their intake of carbohydrates to 20 grams a day (in the first phase -- they can slowly add limited amounts back later), eat a lot of high-protein, high-fat foods, and take dietary supplements.
Since the birth of the Atkins Diet, similar plans have followed, most notably the South Beach Diet in 2003. A modified version of Atkins, the South Beach Diet allows for more vegetables and dairy.
If you've heard about the low-carb craze, then you've probably heard of the "glycemic index," one of the keys to understanding the purpose behind low-carb diets. It's a term diabetics know as they strive to keep blood sugar levels consistent.
Carbs affect blood sugar levels. Foods with a high glycemic index "spike" your blood sugar levels. That is, they make it rise fast and then drop dramatically. Orange juice, for example, has a high glycemic index. Foods with a low glycemic index don't: they keep blood sugar levels steady. High-fiber grains, most vegetables (celery, for example), and some fruits (like apples, cherries, and strawberries) are considered to have a low or fairly low glycemic index. Fat has a glycemic index of 0 -- it has no effect on blood sugar -- which is why high-fat foods often are included on low-carb diets. Research is showing that diets that include low-glycemic foods can help lower cardiovascular risk factors, such as high cholesterol, and "pre-diabetes," a condition that puts you at higher risk for developing diabetes.
Many things affect the actual glycemic response, including what other foods you happen to eat with foods having a low or high glycemic index, how often you eat, whether foods are eaten cooked or raw, how ripe fruits are when eaten, and when or if you've exercised before eating. "The glycemic index is just one of the tools we use to gauge the effects different foods will have on the body, but it's not a perfect science," says O'Shea.How Do Low-Carbohydrate Diets Work?
The reason low-carbohydrate diets are so popular is that in many cases they produce results. People lose weight on them and they lose weight quickly, at least in the short term. But, this weight loss comes primarily in the form of "water-weight," notes national nutrition and fitness expert Pamela Peeke, MD, PhD, author of Fight Fat Over 40, and women's health advisor to the National Women's Health Resource Center in Red Bank, New Jersey, and Washington, DC.
That's because carbohydrates stored by your body are packed with water. When you don't replace your body's fuel source by consuming enough carbohydrates, your body turns to stored carbs for energy, which eliminates a lot of fluid from your body. After the stored carbs are used up, your body eventually turns to fat and lean body tissues for fuel. If you adhere to a low-carb diet for the long run, additional weight loss may come from muscle tissue as well.