The glycemic index is a diet plan that focuses on blood sugar, or blood glucose, levels. The idea behind the diet is that the best way to maintain weight and keep yourself healthy is to keep blood sugar levels from rapidly rising and falling throughout the course of the day.
Physiology
The body prefers the sugar glucose as its main source of energy. Carbohydrate-rich foods, such as pasta, potatoes and fruits, are the best sources of dietary glucose. When you eat a meal with carbohydrates, the carbohydrates are broken down and glucose is absorbed into the bloodstream. The glucose in the blood triggers the release of a hormone called insulin from the pancreas. Insulin binds to glucose and helps the cells absorb it. Some glucose is also stored in the liver as glycogen and used for energy between meals. Extra glucose is converted to fat and stored in fat cells.
Glycemic Index Basics
Different foods affect the glucose and insulin response differently. Some foods cause a rapid increase in glucose levels, while other foods keep glucose levels steady. The idea behind the glycemic index is that rapid increases in glucose levels can lead to weight gain, and keeping glucose levels steady helps you lose or maintain weight. The glycemic index provides a classification for foods based on their effect on glucose levels. Foods are assigned a number that determines whether they are considered high, medium or low on the glycemic index scale. When following a glycemic index diet, you should consume mostly low glycemic index foods and occasionally medium glycemic index foods.
Glycemic Index Scale
Foods on the glycemic index are assigned a number based on a scale ranging from 0 to 100. MayoClinic.com notes that only foods that contain carbohydrates are given a number, since these are the main foods that affect blood sugar levels. Foods with a number from 70 to 100 are considered high. Examples of high glycemic foods include rice, bread, potatoes and watermelon. Foods with a number between 56 and 69 are considered medium. Examples of medium glycemic foods include bananas, pineapple and raisins. Low glycemic foods have a number 55 or lower. Examples of these foods include carrots, apples, beans, lentils and milk.
Claims
One of the major claims of the glycemic index is that it will help you lose weight. Most commercial diets based on this theory claim that by eating low glycemic foods you will be able to lose weight easily without counting calories. Another common claim for a glycemic diet is that keeping your blood sugar levels steady can help reduce your risk of chronic diseases, such as diabetes and heart disease, according to MayoClinic.com.
Considerations
MayoClinic.com notes that a major concern of the glycemic index diet is that foods are ranked independently, instead of how they react in your body with other foods. When you eat, you usually eat a meal that consists of a variety of foods, not one single food. The action of blood sugar is also affected by how much you eat, how ripe the food is and existing health conditions.
