GI, or glycemic index diets, are based on the theory that controlling blood sugar levels promotes weight loss. While on a glycemic index diet, you choose foods that will not cause rapid increases in blood sugar levels, or foods that are low on the glycemic index. According to EveryDiet, glycemic index diets were originally developed in an effort to help diabetics control blood sugar levels.
Physiology
Carbohydrates are the body's main source of energy. When you consume carbohydrates, they move through the digestive system and are broken down into a simple sugar called glucose. When glucose enters the bloodstream, it triggers the release of a hormone called insulin from the pancreas. Insulin helps the cells use glucose for energy. Certain carbohydrates move through the digestive system more quickly than others, causing rapid increases in blood glucose levels as well as a significant release of insulin. Other carbohydrates move through the digestive system slowly and take longer to enter the bloodstream. These slow-moving carbohydrates are the basis of a glycemic index diet.
Definition of Glycemic Index
The glycemic index is a numerical scale from 0 to 100 that classifies foods based on how quickly and how high a carbohydrate raises your blood sugar levels. Foods that are given a rating 70 and higher are considered high-glycemic foods. These foods raise blood glucose significantly and should be avoided on the glycemic index diet. Examples of of high-glycemic foods include white bread, rice, white potatoes, pasta and watermelon. Foods between 56 and 69 are considered medium glycemic index foods. These foods include corn, bananas and pineapple. Low-glycemic foods are those that are rated 55 and lower. These foods have little to no effect on blood glucose levels. Examples of low-glycemic foods include apples, carrots, peanuts, beans, peas and milk.
Following a Glycemic Index Diet
When following a glycemic index diet, you should choose foods that are low on the glycemic index scale most often. You may occasionally consume foods that are rated medium on the glycemic index scale, but they shouldn't provide the basis of your diet. Avoid foods that are high on the glycemic index as much as possible.
Benefits
According to the Linus Pauling Institute, high blood glucose levels and the secretion of excess insulin are thought to contribute to the loss of function of the pancreatic cells that produce insulin. This loss of function causes an increased risk for developing Type 2 diabetes. Excess insulin production may also lead to insulin resistance, which is characterized by the cells' decreased sensitivity to insulin. Insulin resistance is thought to play a role in the development of heart disease. Keeping glucose levels steady can help prevent the excess release of insulin from the pancreas, which can reduce your risk of developing diabetes and cardiovascular disease. Steady blood glucose and insulin levels are also believed to promote weight loss.
Considerations
MayoClinic.com notes that a major problem with the glycemic index diet is that it ranks foods individually, not based on how they interact with each other. This can result in inaccuracies, because most people do not consume one type of food at a time, but rather a meal of many different types of foods. The absorption rate of carbohydrates is based on a number of other factors as well, including how ripe the food is, how much you eat, how the food is prepared and any other existing health problems.
