History

• In the early 1980s, a University of Toronto professor of nutrition named Dr. David Jenkins conceived the idea of the "glycemic index." The glycemic index measures the way foods affect blood sugar. Dr. Jenkins discovered that certain foods, such as white bread and potatoes, caused blood sugar to elevate quickly. When a person's blood sugar spikes, it then crashes, causing him to feel tired and hungry. This causes a cycle of overeating and weight gain.
  
  

Function

• Low-carb diets restrict the number of carbohydrates eaten each day. Because carbs affect the amount of insulin a body produces, eating less carbs causes the insulin level in the dieter's bloodstream to be significantly lower. The body uses insulin as its primary source of fuel, so when this source is limited or depleted, it turns to the next source of fuel, which is fat cells. Not only does this lead to a lower number on the scale, but also curbs cravings for high-carb foods.
  
  

Types

• Since a rise in popularity during the late 1990s, numerous low-carb diets have been created. While they are all based on the restriction of carbs in a diet, there are some differences. The Atkins Diet was the first to make low-carb popular and basically restricts carbs. The South Beach Diet emphasizes low-carbs as well as low-fat foods. The Zone Diet promotes a diet with foods with a low glycemic index and low in saturated fats. The Sonoma Diet restricts food high in fat, as well as sugars and starches. This low-carb diet encourages portion control, as well.
  
  

Benefits

• Aside from weight loss, there are numerous health benefits associated with low-carb diets. According to a study by the University of Western Ontario, a low-carb diet lowers cholesterol and triglycerides while raising HDL (good cholesterol). Low-carb diets reduce blood glucose and insulin, while improving insulin sensitivity. This is paramount for people with insulin-related illnesses, such as diabetes and polycystic ovarian syndrome. Low-carb diets lower blood pressure and can be helpful in the treatment of seizure disorders.
  
  

Warning

• When starting a low-carb diet, it is common for people to focus on eating lots of protein. Most low-carb diets promote the inclusion of a variety of vegetables and certain fruits. It is imperative to include these foods as part of any diet, low-carb or otherwise, for balanced nutrition. Dieters should also opt for protein sources that are low in saturated fat, such as chicken, legumes, turkey, fish and lean cuts of beef. Too much fatty, red meat can contribute to cancer, heart disease and a slew of other medical problems.